Middle of eclipse season June 20

Various stages of an annular solar eclipse from Brocken Inaglory via Wikimedia Commons.

Eclipses of the new moon and full moon don’t occur every month, because the moon’s orbital plane is inclined by about 5 degrees to the plane of the ecliptic (Earth’s orbital plane). But the moon’s orbital path does intersect the Earth’s orbital plane at two points called nodes. Whenever these lunar nodes point directly at the sun, it marks the midpoint of the eclipse season. The lunar nodes line up with the sun in periods of about 173.3 days, or nearly 10 days shy of six calendar months.

The middle of the eclipse season (when the line of nodes points directly the sun) last took place on December 30, 2019. The middle of the eclipse season will next occur on June 20, 2020, and then – after that – on December 11, 2020.

Whenever the lunar nodes point directly at the sun, it marks the midpoint of the approximate 35-day eclipse season. In the year 2020, the middle of the eclipse season occurs on June 20, 2020, and then again on December 11, 2020. Image via Go Science Go.

An eclipse season lasts for approximately 35 days, and any new moon or full moon occurring within this time period will undergo an eclipse. Given that the lunar month (period of time between successive new moons or successive full moons) is about 29.5 days long, a minimum of two eclipses (one solar and one lunar, in either order), or a maximum of three eclipses (either lunar/solar/lunar, or solar/lunar/solar) can take place in one eclipse season.

Eclipses are all about alignments. In a solar eclipse, the sun, moon and Earth line up, with the moon in the middle. Image via NASA.

In a lunar eclipse, the sun, Earth and moon line up, with the Earth in the middle. Image via NASA.

Most often, there are only two eclipses in one eclipse season. For three eclipses to occur, the first one has to come quite early in the eclipse season to allow for a third eclipse near the end. For the first time since the year 2018, we’ll have three eclipses in one eclipse season in 2020. We won’t have three eclipses in one eclipse season again until the year 2029.

The year 2020:

June 5, 2020: Penumbral lunar eclipse
June 21, 2020: Annular solar eclipse
July 5, 2020: Penumbral lunar eclipse

Read more: How often are there 3 eclipses in a month?

If an eclipse happens at or near the mid-point of the eclipse season, as the upcoming solar eclipse on June 21st does, then we’ll have a central eclipse. If it’s a solar eclipse, the central eclipse presents either a total or annular eclipse of the sun; or if it’s a lunar eclipse, the central eclipse features a total eclipse of the moon. If the eclipse falls near the beginning or the end of the eclipse season, it’s either a penumbral eclipse of the moon or small partial eclipse of the sun.

Read more: Annular eclipse of the sun on June 21, 2020

Because the lunar eclipses occur so early and so late in the June/July 2020 eclipse season, the lunar eclipses on June 5, 2020, and July 5, 2020, will be extremely faint and hard-to-see penumbral lunar eclipses. See the illustration of these eclipses below.

The next eclipse season in June/July 2020 will showcase three eclipses (lunar/solar/lunar). Image via Wikipedia.

On the other hand, the solar eclipse on June 21, 2020, which takes place almost dead center in the eclipse season, will present a central eclipse, exhibiting an annular eclipse of the sun. See diagram above.

Thirty-eight eclipse seasons (19 eclipse years) are almost exactly commensurate to 223 lunar months, a period of 18 years and 11 1/3 days (four intervening leap years) or 18 years and 10 1/3 days (5 intervening leap years). Therefore, the eclipses coming up in June/July 2038 display similar geometries to those in June/July 2020. This 223-lunar-month period of time is known as the Saros.

The year 2020:

June 5, 2020: Penumbral lunar eclipse
June 21, 2020: Annular solar eclipse
July 5, 2020: Penumbral lunar eclipse

The year 2038:

June 17, 2038: Penumbral lunar eclipse
July 2, 2038: Annular solar eclipse
July 16, 2038: Penumbral lunar eclipse

Interestingly, the Sar or Half Saros, representing a period of 111.5 lunar months (9 years and 5 2/3 days), gives us alternating eclipses (solar/lunar/solar) of similar character. Contrast the years 2020 and 2038 listed above with the years 2029 and 2047 listed below.

Many people are familiar with the Saros period of 223 lunar months (18.03 years), whereby a similar progression of eclipses takes place in one eclipse season (lunar/solar/lunar). Less well known, the Sar or Half Saros of 111.5 lunar months (9.015 years) also presents 3 eclipses in one eclipse season, though in alternate order (solar/lunar/solar). Image via Wikipedia.

The year 2029:

June 12, 2029: Partial solar eclipse
June 26, 2029: Total lunar eclipse
July 11, 2029; Partial solar eclipse

The year 2047:

June 23, 2047: Partial solar eclipse
July 7, 2047: Total lunar eclipse
July 22, 2047: Partial solar eclipse

The eclipse master Fred Espenak tells us a Saros series can last anywhere from 1,226 to 1,550 years and is made up of 69 to 87 eclipses. A Saros series, whether it be solar or lunar, always starts off with skimpy eclipses and ends with skimpy eclipses. The middle of a Saros series brings about the closest alignment of the three celestial bodies – Earth, sun and moon – whereby they line up almost perfectly in space.

In any eclipse season where there are three eclipses, the first and third eclipses are meager productions whereas the middle eclipse is a highly visible central eclipse. And in any Saros series, the early and late eclipses are also paltry at best, whereas the middle part of a Saros series presents central eclipses.

Here’s something that may surprise you: Any eclipse happening early in an eclipse season always occurs late in a Saros series – and vice versa. For example, let’s look at the upcoming three-eclipse season in June/July 2020:

The year 2020:

June 5, 2020: Penumbral lunar eclipse
June 21, 2020: Annular solar eclipse
July 5, 2020: Penumbral lunar eclipse

The first eclipse of the eclipse season on June 5, 2020, belongs to Lunar Saros 111 and presents the 67th of 71 eclipses in this Saros series. Yet, the third and final eclipse of the eclipse season on July 5, 2020, belongs to Lunar Saros 149, and features the third of 71 eclipses in this particular Saros series.

Unsurprisingly, perhaps, the second (or middle) eclipse of the eclipse season on June 21, 2020, is the 36th of 70 eclipses in Solar Saros 137.

The plane of the moon’s orbit is inclined at 5 degrees to the plane of Earth’s orbit around the sun (the ecliptic). In this diagram, however, the ecliptic is portrayed as the sun’s apparent annual path in front of the constellations of the zodiac. The moon’s orbit intersects the ecliptic at two points called nodes (labeled here as N1 and N2). It’s the middle of the eclipse season whenever this line of nodes points directly at the sun. In the above diagram, the line of nodes does not point at the sun.

Bottom line: The middle of the eclipse season falls on June 20, 2020, and this eclipse season produces three eclipses (lunar/solar/lunar), though only the second of these three eclipses – the annular “ring of fire” eclipse on June 21, 2020 – will produce any real theatrics on the great stage of the sky.

from EarthSky https://ift.tt/2UkWFi1

Various stages of an annular solar eclipse from Brocken Inaglory via Wikimedia Commons.

Eclipses of the new moon and full moon don’t occur every month, because the moon’s orbital plane is inclined by about 5 degrees to the plane of the ecliptic (Earth’s orbital plane). But the moon’s orbital path does intersect the Earth’s orbital plane at two points called nodes. Whenever these lunar nodes point directly at the sun, it marks the midpoint of the eclipse season. The lunar nodes line up with the sun in periods of about 173.3 days, or nearly 10 days shy of six calendar months.

The middle of the eclipse season (when the line of nodes points directly the sun) last took place on December 30, 2019. The middle of the eclipse season will next occur on June 20, 2020, and then – after that – on December 11, 2020.

Whenever the lunar nodes point directly at the sun, it marks the midpoint of the approximate 35-day eclipse season. In the year 2020, the middle of the eclipse season occurs on June 20, 2020, and then again on December 11, 2020. Image via Go Science Go.

An eclipse season lasts for approximately 35 days, and any new moon or full moon occurring within this time period will undergo an eclipse. Given that the lunar month (period of time between successive new moons or successive full moons) is about 29.5 days long, a minimum of two eclipses (one solar and one lunar, in either order), or a maximum of three eclipses (either lunar/solar/lunar, or solar/lunar/solar) can take place in one eclipse season.

Eclipses are all about alignments. In a solar eclipse, the sun, moon and Earth line up, with the moon in the middle. Image via NASA.

In a lunar eclipse, the sun, Earth and moon line up, with the Earth in the middle. Image via NASA.

Most often, there are only two eclipses in one eclipse season. For three eclipses to occur, the first one has to come quite early in the eclipse season to allow for a third eclipse near the end. For the first time since the year 2018, we’ll have three eclipses in one eclipse season in 2020. We won’t have three eclipses in one eclipse season again until the year 2029.

The year 2020:

June 5, 2020: Penumbral lunar eclipse
June 21, 2020: Annular solar eclipse
July 5, 2020: Penumbral lunar eclipse

Read more: How often are there 3 eclipses in a month?

If an eclipse happens at or near the mid-point of the eclipse season, as the upcoming solar eclipse on June 21st does, then we’ll have a central eclipse. If it’s a solar eclipse, the central eclipse presents either a total or annular eclipse of the sun; or if it’s a lunar eclipse, the central eclipse features a total eclipse of the moon. If the eclipse falls near the beginning or the end of the eclipse season, it’s either a penumbral eclipse of the moon or small partial eclipse of the sun.

Read more: Annular eclipse of the sun on June 21, 2020

Because the lunar eclipses occur so early and so late in the June/July 2020 eclipse season, the lunar eclipses on June 5, 2020, and July 5, 2020, will be extremely faint and hard-to-see penumbral lunar eclipses. See the illustration of these eclipses below.

The next eclipse season in June/July 2020 will showcase three eclipses (lunar/solar/lunar). Image via Wikipedia.

On the other hand, the solar eclipse on June 21, 2020, which takes place almost dead center in the eclipse season, will present a central eclipse, exhibiting an annular eclipse of the sun. See diagram above.

Thirty-eight eclipse seasons (19 eclipse years) are almost exactly commensurate to 223 lunar months, a period of 18 years and 11 1/3 days (four intervening leap years) or 18 years and 10 1/3 days (5 intervening leap years). Therefore, the eclipses coming up in June/July 2038 display similar geometries to those in June/July 2020. This 223-lunar-month period of time is known as the Saros.

The year 2020:

June 5, 2020: Penumbral lunar eclipse
June 21, 2020: Annular solar eclipse
July 5, 2020: Penumbral lunar eclipse

The year 2038:

June 17, 2038: Penumbral lunar eclipse
July 2, 2038: Annular solar eclipse
July 16, 2038: Penumbral lunar eclipse

Interestingly, the Sar or Half Saros, representing a period of 111.5 lunar months (9 years and 5 2/3 days), gives us alternating eclipses (solar/lunar/solar) of similar character. Contrast the years 2020 and 2038 listed above with the years 2029 and 2047 listed below.

Many people are familiar with the Saros period of 223 lunar months (18.03 years), whereby a similar progression of eclipses takes place in one eclipse season (lunar/solar/lunar). Less well known, the Sar or Half Saros of 111.5 lunar months (9.015 years) also presents 3 eclipses in one eclipse season, though in alternate order (solar/lunar/solar). Image via Wikipedia.

The year 2029:

June 12, 2029: Partial solar eclipse
June 26, 2029: Total lunar eclipse
July 11, 2029; Partial solar eclipse

The year 2047:

June 23, 2047: Partial solar eclipse
July 7, 2047: Total lunar eclipse
July 22, 2047: Partial solar eclipse

The eclipse master Fred Espenak tells us a Saros series can last anywhere from 1,226 to 1,550 years and is made up of 69 to 87 eclipses. A Saros series, whether it be solar or lunar, always starts off with skimpy eclipses and ends with skimpy eclipses. The middle of a Saros series brings about the closest alignment of the three celestial bodies – Earth, sun and moon – whereby they line up almost perfectly in space.

In any eclipse season where there are three eclipses, the first and third eclipses are meager productions whereas the middle eclipse is a highly visible central eclipse. And in any Saros series, the early and late eclipses are also paltry at best, whereas the middle part of a Saros series presents central eclipses.

Here’s something that may surprise you: Any eclipse happening early in an eclipse season always occurs late in a Saros series – and vice versa. For example, let’s look at the upcoming three-eclipse season in June/July 2020:

The year 2020:

June 5, 2020: Penumbral lunar eclipse
June 21, 2020: Annular solar eclipse
July 5, 2020: Penumbral lunar eclipse

The first eclipse of the eclipse season on June 5, 2020, belongs to Lunar Saros 111 and presents the 67th of 71 eclipses in this Saros series. Yet, the third and final eclipse of the eclipse season on July 5, 2020, belongs to Lunar Saros 149, and features the third of 71 eclipses in this particular Saros series.

Unsurprisingly, perhaps, the second (or middle) eclipse of the eclipse season on June 21, 2020, is the 36th of 70 eclipses in Solar Saros 137.

The plane of the moon’s orbit is inclined at 5 degrees to the plane of Earth’s orbit around the sun (the ecliptic). In this diagram, however, the ecliptic is portrayed as the sun’s apparent annual path in front of the constellations of the zodiac. The moon’s orbit intersects the ecliptic at two points called nodes (labeled here as N1 and N2). It’s the middle of the eclipse season whenever this line of nodes points directly at the sun. In the above diagram, the line of nodes does not point at the sun.

Bottom line: The middle of the eclipse season falls on June 20, 2020, and this eclipse season produces three eclipses (lunar/solar/lunar), though only the second of these three eclipses – the annular “ring of fire” eclipse on June 21, 2020 – will produce any real theatrics on the great stage of the sky.

from EarthSky https://ift.tt/2UkWFi1

Jupiter gives us Pluto in 2020

Mosaic image of Pluto and its largest moon Charon, captured around the time the New Horizons spacecraft swept closest to them on July 14, 2015. Image via NASA/ JHUAPL/ SwRI.

The year 2020 is exceptional for Jupiter and Pluto. These two worlds are having a triple conjunction this year. They’ll come together, move apart, and come together again three times in 2020. The first conjunction took place on April 5. The second one will come on June 30, and the final one on November 12. Because all of these Jupiter-Pluto conjunctions happen when these two planets are actually visible in our night sky (as opposed to being lost in the sun’s glare), this year’s Jupiter-Pluto alignment may be the best for centuries to come.

This year, very bright Jupiter and very faint Pluto will remain near each other throughout the year, closely aligned in front of the constellation Sagittarius. Pluto requires a telescope to be seen. No telescope? Try NASA’s Night Sky Network to find star parties and/or astronomy clubs near you.

And you don’t need a telescope to use your imagination. Throughout 2020, dazzling Jupiter will enable us to envision Pluto with the mind’s eye on the sky’s dome. First find Jupiter and – presto – you’ve nearly stumbled upon Pluto. Just remember, Jupiter outshines Pluto by several million times.

Where are these worlds now? Both Pluto and Jupiter came out from behind the sun in January 2020, and then hovered low in the east before sunrise. Now – in June 2020 – these two worlds come up at late evening at mid-northern latitudes, and at mid-evening for the Southern Hemisphere. Jupiter and Pluto climb upward throughout the nighttime morning hours, to reach the meridian in the predawn/dawn sky on these June 2020 mornings.

Jupiter is very bright. You can’t miss it from late night until dawn on the nights of June 6 to 8, 2020. On June 8, the waning gibbous moon sweeps 1.3 degrees south of Pluto, and then – a few hours later – the moon swings 2.2 degrees south of Jupiter (at 17:19 UTC on June 8, 2020). Both Jupiter and Pluto are traveling in retrograde (westward) all month long, though Jupiter at a faster pace. Jupiter will catch up with Pluto on June 30, 2020, to stage the second of this year’s three Jupiter/Pluto conjunctions.

Of course, although Jupiter and Pluto nearly align along the same line of sight throughout 2020, these two worlds aren’t close together in space. Jupiter is a bit more than 5 astronomical units (AU) from the sun, while Pluto lodges way beyond Jupiter, in the Kuiper Belt, at about 34 AU from the sun. One astronomical unit (AU) = one sun/Earth distance.

Jupiter’s and Pluto’s present distance in AU via Heavens-Above

Here’s some observational data about Pluto for 2020, from In-the-Sky.org

Steven Bellavia in Mattituck, New York, captured Pluto on 2 separate nights, June 24 and June 27, 2019. In this animated gif, you can see that Pluto moved in front of the stars between those 2 nights. Steven wrote: “Most of the motion you see is actually from the Earth, not Pluto, since our motion changes our perspective of the much-closer Pluto against the backdrop of the much-farther stars.” Thanks, Steven!

Two planets are said to be in conjunction whenever they reside north and south of one another on the sky’s dome. Conjunctions of Jupiter and Pluto recur in periods of 12 to 13 years. The previous Jupiter-Pluto conjunction happened on December 11, 2007, and the one before that on December 2, 1994. After 2020, the next Jupiter-Pluto conjunction will occur on February 4, 2033, and the one following that on April 12, 2045. But the gap between Jupiter and Pluto at each one of these conjunctions is quite far apart, and the conjunctions of 1994, 2007, and 2033 happen so close to the sun that even Jupiter is lost in the sun’s glare.

Far and away, 2020 presents the best alignment of Jupiter and Pluto in the 21st century (2001 to 2100). What’s more, Jupiter and Pluto stage three conjunctions this year, as Jupiter passes less than one degree north of Pluto at each conjunction on April 5, June 30 and November 12, 2020. (For reference, the moon’s angular diameter spans about 1/2 degree of sky.) All of these conjunctions in 2020 take place in front of the constellation Sagittarius, with Jupiter first passing Pluto on April 5 in prograde (going eastward in front of the backdrop stars), then sweeping past Pluto on June 30 in retrograde (going westward relative to the background stars), and then for the final Jupiter-Pluto conjunction on November 12 in prograde (eastward).

All three Jupiter-Saturn conjunctions on April 5, June 30 and November 12, 2020 take pace place in front of the constellation Sagittarius, not far from the 5th-magnitude star 56 Sagittarii. Constellation chart via International Astronomical Union (IAU).

Most of the time, a Jupiter-Pluto conjunction in any year is a solitary event, as Jupiter laps Pluto going eastward, and never looks back. Triple conjunctions of Jupiter and Pluto – which occur over a period of about 7.4 months – are rare because Jupiter has to first catch Pluto going prograde (eastward), then in retrograde (westward) and then in prograde (eastward) again. The three-peat performance last happened in 1955-56 (November 2, 1955; February 8 and June 16, 1956), and will next occur in 2106-07 (July 13 and November 2, 2106; February 19, 2107). Yet, all three conjunctions in 1955-56 were widely spaced, and all three conjunctions in 2106-07 will be widely spaced, too.

Illustration showing why a superior planet appears to go in retrograde (westward in front of the backdrop stars of the zodiac). As seen from the north side of the solar system, all the planets orbit counter-clockwise. When the faster-moving Earth goes by a slower-moving superior planet, that planet appears to go backward (in retrograde). In 2020, Mars is in retrograde from September 9 to November 15, Jupiter from May 14 to September 13, and Saturn from May 11 to September 29. Image via Wikimedia Commons.

In other words, as we said above, 2020 may well showcase the best Jupiter-Pluto alignment for centuries to come. Most excitingly, both Jupiter and Pluto will reach opposition in mid-July 2020. At opposition, a superior planet – any planet revolving around the sun outside of Earth’s orbit – resides opposite the sun in Earth’s sky.

Opposition happens when Earth flies between a superior planet, like Mars, and the sun. This happens yearly for most of the outer planets (and every other year for Mars). Illustration via Heavens-Above.

At opposition, a superior planet (or superior dwarf planet) rises at sunset and sets at sunrise, and is out all night long. It’s at opposition that a planet shines at its brightest best in Earth’s sky, and it’s at or near opposition that a planet comes closest to Earth for the year.

Jupiter reaches opposition on July 14, 2020, at about 8:00 UTC, and comes closest to Earth on July 15, 2020, at about 10:00 UTC.

Pluto reaches opposition on July 15, 2020, at about 19:00 UTC, and comes closest to Earth on July 13, 2020, at about 9:00 UTC.

In an uncanny bit of timing, the oppositions of Jupiter and Pluto happen almost concurrently in mid-July 2020. A planet reaches opposition midway through a retrograde. However, since Pluto resides so much farther from the sun than Jupiter does, Pluto’s retrograde lasts nearly 1 1/2 months (six weeks) longer than Jupiter’s four-month retrograde. So for near-unison oppositions, Pluto’s retrograde has to start – and end – approximately three weeks before – and after – Jupiter’s retrograde.

Jupiter and Pluto retrograde/opposition in 2020

Jupiter begins retrograde: May 14, 2020, in front of the constellation Sagittarius
Jupiter at opposition: July 14, 2020, in front of the constellation Sagittarius
Jupiter ends retrograde: September 13, 2020, in front of the constellation Sagittarius

Pluto begins retrograde: April 25, 2020, in front of the constellation Sagittarius
Pluto at opposition: July 15, 2020, in front of the constellation Sagittarius
Pluto ends retrograde: October 4, 2020, in front of the constellation Sagittarius

Jupiter-Pluto conjunction tables via Richard Nolle

Call it serendipity or synergy – or whatever – but the spectacular alignment of the king planet Jupiter with the dwarf planet Pluto doesn’t get much better than in 2020. A similarly good Jupiter-Pluto rendezvous might not happen again for a number of centuries to come.

Pluto as seen with a 12″ S/C telescope (14.3 mag.) on July 10, 2015. Photo by Efrain Morales of Sociedad de Astronomia del Caribe. More information about Pluto’s current location.

Bottom line: Jupiter is as easy to find as the dwarf planet Pluto is difficult. Jupiter is bright! It ranks as the fourth-brightest celestial object to light up the heavens, after the sun, moon and Venus. Pluto, on the other hand, is 1,600 times dimmer than the faintest star visible to the unaided eye. But Jupiter can help you find – or at least envision – Pluto this year. That’s because these two worlds are having a triple conjunction this year; they’re near each other on the sky’s dome all year and will come exceptionally close 3 times in 2020.

from EarthSky https://ift.tt/2XkisVG

Mosaic image of Pluto and its largest moon Charon, captured around the time the New Horizons spacecraft swept closest to them on July 14, 2015. Image via NASA/ JHUAPL/ SwRI.

The year 2020 is exceptional for Jupiter and Pluto. These two worlds are having a triple conjunction this year. They’ll come together, move apart, and come together again three times in 2020. The first conjunction took place on April 5. The second one will come on June 30, and the final one on November 12. Because all of these Jupiter-Pluto conjunctions happen when these two planets are actually visible in our night sky (as opposed to being lost in the sun’s glare), this year’s Jupiter-Pluto alignment may be the best for centuries to come.

This year, very bright Jupiter and very faint Pluto will remain near each other throughout the year, closely aligned in front of the constellation Sagittarius. Pluto requires a telescope to be seen. No telescope? Try NASA’s Night Sky Network to find star parties and/or astronomy clubs near you.

And you don’t need a telescope to use your imagination. Throughout 2020, dazzling Jupiter will enable us to envision Pluto with the mind’s eye on the sky’s dome. First find Jupiter and – presto – you’ve nearly stumbled upon Pluto. Just remember, Jupiter outshines Pluto by several million times.

Where are these worlds now? Both Pluto and Jupiter came out from behind the sun in January 2020, and then hovered low in the east before sunrise. Now – in June 2020 – these two worlds come up at late evening at mid-northern latitudes, and at mid-evening for the Southern Hemisphere. Jupiter and Pluto climb upward throughout the nighttime morning hours, to reach the meridian in the predawn/dawn sky on these June 2020 mornings.

Jupiter is very bright. You can’t miss it from late night until dawn on the nights of June 6 to 8, 2020. On June 8, the waning gibbous moon sweeps 1.3 degrees south of Pluto, and then – a few hours later – the moon swings 2.2 degrees south of Jupiter (at 17:19 UTC on June 8, 2020). Both Jupiter and Pluto are traveling in retrograde (westward) all month long, though Jupiter at a faster pace. Jupiter will catch up with Pluto on June 30, 2020, to stage the second of this year’s three Jupiter/Pluto conjunctions.

Of course, although Jupiter and Pluto nearly align along the same line of sight throughout 2020, these two worlds aren’t close together in space. Jupiter is a bit more than 5 astronomical units (AU) from the sun, while Pluto lodges way beyond Jupiter, in the Kuiper Belt, at about 34 AU from the sun. One astronomical unit (AU) = one sun/Earth distance.

Jupiter’s and Pluto’s present distance in AU via Heavens-Above

Here’s some observational data about Pluto for 2020, from In-the-Sky.org

Steven Bellavia in Mattituck, New York, captured Pluto on 2 separate nights, June 24 and June 27, 2019. In this animated gif, you can see that Pluto moved in front of the stars between those 2 nights. Steven wrote: “Most of the motion you see is actually from the Earth, not Pluto, since our motion changes our perspective of the much-closer Pluto against the backdrop of the much-farther stars.” Thanks, Steven!

Two planets are said to be in conjunction whenever they reside north and south of one another on the sky’s dome. Conjunctions of Jupiter and Pluto recur in periods of 12 to 13 years. The previous Jupiter-Pluto conjunction happened on December 11, 2007, and the one before that on December 2, 1994. After 2020, the next Jupiter-Pluto conjunction will occur on February 4, 2033, and the one following that on April 12, 2045. But the gap between Jupiter and Pluto at each one of these conjunctions is quite far apart, and the conjunctions of 1994, 2007, and 2033 happen so close to the sun that even Jupiter is lost in the sun’s glare.

Far and away, 2020 presents the best alignment of Jupiter and Pluto in the 21st century (2001 to 2100). What’s more, Jupiter and Pluto stage three conjunctions this year, as Jupiter passes less than one degree north of Pluto at each conjunction on April 5, June 30 and November 12, 2020. (For reference, the moon’s angular diameter spans about 1/2 degree of sky.) All of these conjunctions in 2020 take place in front of the constellation Sagittarius, with Jupiter first passing Pluto on April 5 in prograde (going eastward in front of the backdrop stars), then sweeping past Pluto on June 30 in retrograde (going westward relative to the background stars), and then for the final Jupiter-Pluto conjunction on November 12 in prograde (eastward).

All three Jupiter-Saturn conjunctions on April 5, June 30 and November 12, 2020 take pace place in front of the constellation Sagittarius, not far from the 5th-magnitude star 56 Sagittarii. Constellation chart via International Astronomical Union (IAU).

Most of the time, a Jupiter-Pluto conjunction in any year is a solitary event, as Jupiter laps Pluto going eastward, and never looks back. Triple conjunctions of Jupiter and Pluto – which occur over a period of about 7.4 months – are rare because Jupiter has to first catch Pluto going prograde (eastward), then in retrograde (westward) and then in prograde (eastward) again. The three-peat performance last happened in 1955-56 (November 2, 1955; February 8 and June 16, 1956), and will next occur in 2106-07 (July 13 and November 2, 2106; February 19, 2107). Yet, all three conjunctions in 1955-56 were widely spaced, and all three conjunctions in 2106-07 will be widely spaced, too.

Illustration showing why a superior planet appears to go in retrograde (westward in front of the backdrop stars of the zodiac). As seen from the north side of the solar system, all the planets orbit counter-clockwise. When the faster-moving Earth goes by a slower-moving superior planet, that planet appears to go backward (in retrograde). In 2020, Mars is in retrograde from September 9 to November 15, Jupiter from May 14 to September 13, and Saturn from May 11 to September 29. Image via Wikimedia Commons.

In other words, as we said above, 2020 may well showcase the best Jupiter-Pluto alignment for centuries to come. Most excitingly, both Jupiter and Pluto will reach opposition in mid-July 2020. At opposition, a superior planet – any planet revolving around the sun outside of Earth’s orbit – resides opposite the sun in Earth’s sky.

Opposition happens when Earth flies between a superior planet, like Mars, and the sun. This happens yearly for most of the outer planets (and every other year for Mars). Illustration via Heavens-Above.

At opposition, a superior planet (or superior dwarf planet) rises at sunset and sets at sunrise, and is out all night long. It’s at opposition that a planet shines at its brightest best in Earth’s sky, and it’s at or near opposition that a planet comes closest to Earth for the year.

Jupiter reaches opposition on July 14, 2020, at about 8:00 UTC, and comes closest to Earth on July 15, 2020, at about 10:00 UTC.

Pluto reaches opposition on July 15, 2020, at about 19:00 UTC, and comes closest to Earth on July 13, 2020, at about 9:00 UTC.

In an uncanny bit of timing, the oppositions of Jupiter and Pluto happen almost concurrently in mid-July 2020. A planet reaches opposition midway through a retrograde. However, since Pluto resides so much farther from the sun than Jupiter does, Pluto’s retrograde lasts nearly 1 1/2 months (six weeks) longer than Jupiter’s four-month retrograde. So for near-unison oppositions, Pluto’s retrograde has to start – and end – approximately three weeks before – and after – Jupiter’s retrograde.

Jupiter and Pluto retrograde/opposition in 2020

Jupiter begins retrograde: May 14, 2020, in front of the constellation Sagittarius
Jupiter at opposition: July 14, 2020, in front of the constellation Sagittarius
Jupiter ends retrograde: September 13, 2020, in front of the constellation Sagittarius

Pluto begins retrograde: April 25, 2020, in front of the constellation Sagittarius
Pluto at opposition: July 15, 2020, in front of the constellation Sagittarius
Pluto ends retrograde: October 4, 2020, in front of the constellation Sagittarius

Jupiter-Pluto conjunction tables via Richard Nolle

Call it serendipity or synergy – or whatever – but the spectacular alignment of the king planet Jupiter with the dwarf planet Pluto doesn’t get much better than in 2020. A similarly good Jupiter-Pluto rendezvous might not happen again for a number of centuries to come.

Pluto as seen with a 12″ S/C telescope (14.3 mag.) on July 10, 2015. Photo by Efrain Morales of Sociedad de Astronomia del Caribe. More information about Pluto’s current location.

Bottom line: Jupiter is as easy to find as the dwarf planet Pluto is difficult. Jupiter is bright! It ranks as the fourth-brightest celestial object to light up the heavens, after the sun, moon and Venus. Pluto, on the other hand, is 1,600 times dimmer than the faintest star visible to the unaided eye. But Jupiter can help you find – or at least envision – Pluto this year. That’s because these two worlds are having a triple conjunction this year; they’re near each other on the sky’s dome all year and will come exceptionally close 3 times in 2020.

from EarthSky https://ift.tt/2XkisVG

Want to see Saturn’s rings? Read me 1st

James Martin in Albuquerque, New Mexico, caught this photo of Saturn at its 2017 opposition, when the rings were maximally tilted toward Earth. Opposition marks the middle of the best time of year to see an outer planet. The 2020 opposition will happen on July 20.

It’s that magical time of year again, when our solar system’s most beautiful planet – Saturn – is becoming well placed for viewing in our sky. Saturn looks starlike to the eye alone, but it shines steadily, as planets tend to do, and it has a distinct golden color. So Saturn is a lovely object to view with the eye alone. Binoculars will enhance its color, and even small telescopes will show you Saturn’s rings. Veteran observer Alan MacRobert at SkyandTelescope.com has written:

The rings of Saturn should be visible in even the smallest telescope at 25x [magnified by 25 times]. A good 3-inch scope at 50x [magnified by 50 times] can show them as a separate structure detached on all sides from the ball of the planet.

You want to see Saturn’s rings. We know you do! With the moon passing Saturn this week, it’s a good time to identify the planet with the eye alone. See the chart below:

The moon sweeps past Saturn on the nights of June 7 and 8, 2020. Read more.

See, on the chart above, how Saturn is near a brighter planet, Jupiter? These two planets will be near each other throughout 2020. Jupiter outshines all the stars, so its proximity to Saturn will make finding Saturn a breeze. And, before this year ends, Jupiter and Saturn will have a great conjunction?

Okay, got Saturn? It’ll be great fun to watch it and Jupiter throughout the rest of 2020. Now … about that telescope. One possibility is to start scouting out a star party near you, where amateur astronomers are set up to show you telescopic objects. Check the club map at NASA’s Night Sky Network to find star parties. Or try this list of astronomy clubs by state from the Astronomical League. Or call a local university or science museum and ask about star parties. Or maybe a neighbor, or friend, has a telescope stashed in a closet? More possibilities:

Astronomy Clubs Near Me & Organizations, from SkyandTelescope.com.

2018 Astronomy Club Directory, from Go-Astronomy.com.

Astronomy Clubs Near Me, from LoveTheNightSky.com.

Okay, so you can find Saturn in the sky, and you’ve found a star party to attend. Here are some things to think about before your Saturn ring-viewing session:

1. Telescope. Don’t expect to see the rings in binoculars. You really do need a telescope. A bigger telescope will show you more than a smaller telescope. Check out the contrast between the two photos below.

These images suggest how the ringed planet Saturn might look when seen through a telescope with an aperture 4 inches (100 mm) in diameter (top) and through a larger instrument with an 8-inch (200 mm) aperture (bottom). Image via SkyandTelescope.com/ NASA/ Hubble Space Telescope.

2. Tilt. Notice the tilt of the rings. As with so much in space (and on Earth), the appearance of Saturn’s rings from Earth is cyclical. In 2017, the north side of the rings opened up most widely (27 degrees), as seen from Earth. That’s the most open this face of the rings has been since since 1988. In 2020, we’re past the peak of the north ring face opening, but Saturn’s rings are still inclined at nearly 22 degrees from edge-on, still exhibiting their northern face. By the year 2025, the rings will appear edge-on as seen from Earth. At such times, because the rings are so thin, it’s possible to view Saturn through a telescope as if it has no rings at all! After that, we’ll begin to see the south side of Saturn’s rings and their openness will gradually increase to a maximum inclination of 27 degrees by May 2032.

The tilt of Saturn’s rings has a great impact on the planet’s overall brightness as seen from Earth. In years when Saturn’s rings are edge-on as seen from Earth (2009 and 2025), Saturn does appear considerably dimmer than in years when Saturn’s rings are maximally tilted toward Earth (2017 and 2032). These Saturn views were simulated with a computer program written by Tom Ruen. Image via Wikimedia Commons.

3. 3D. Ask yourself … do Saturn’s rings look three-dimensional? Again quoting Alan MacRobert at SkyandTelescope.com:

Saturn has a more three-dimensional appearance than any other object in the sky — at least that’s how it looks to me with a 6-inch ‘scope on a night of fine seeing.

4. Seeing. What was Alan talking about in that quote above when he mentioned seeing? Both amateur and professional astronomers talk about the night’s seeing, which affects how clearly and sharply you can see a telescopic image. Seeing isn’t a quality of the telescope; it’s a quality of the air above you. It’s the reason the stars twinkle more on some nights than others. When the air is particularly turbulent, astronomers say there’s bad seeing. The images at the telescope shimmy and dance. When the air is particularly still, astronomers say there’s good seeing. Seeing can shift from moment to moment, as parcels of air move above you. So, as you’re gazing at Saturn, stand as quietly as you can – for as long as you can – and just look. You’ll notice moments when the image suddenly comes into sharper focus.

Turbulent air makes for poor seeing. But the air above you can also “settle” suddenly. When viewing Saturn, wait for those moments. Image via AstronomyNotes.com.

5. Other things to think about. Once you get comfortable viewing Saturn – assuming you’re able to view it again and again, with a telescope of your own – you’ll begin to notice details in the rings. Today, thanks to spacecraft, we know that Saturn’s rings are incredibly detailed. But, as you stand at your telescope gazing upward, you might be thrilled to witness just one primary division in the rings, the Cassini Division between the A and B rings, named for its French discoverer Jean Cassini. Seeing this dark division is a good test of the night’s seeing and your telescope’s optical quality, and also of your own eyes’ ability to simply look and notice what you see. By the way, if you’re looking at the rings – which means you’re viewing Saturn through a telescope – look also for one or more of Saturn’s many moons, most notably Titan.

Have fun!

Alas, you won’t see Saturn look like this through a telescope. This is a spacecraft view, from Cassini in 2016, showing Saturn’s northern hemisphere. Image via NASA/ JPL-Caltech/ Space Science Institute.

Bottom line: In 2020, Saturn’s opposition – marking the middle of the best time of year to see it – comes on July 20. Here are some tips for beginners who want to see Saturn’s rings.

Read more … Viewing Saturn: Rings, Planet and Moons

Help EarthSky keep going! Please donate.

from EarthSky https://ift.tt/2Y9hEUV

James Martin in Albuquerque, New Mexico, caught this photo of Saturn at its 2017 opposition, when the rings were maximally tilted toward Earth. Opposition marks the middle of the best time of year to see an outer planet. The 2020 opposition will happen on July 20.

It’s that magical time of year again, when our solar system’s most beautiful planet – Saturn – is becoming well placed for viewing in our sky. Saturn looks starlike to the eye alone, but it shines steadily, as planets tend to do, and it has a distinct golden color. So Saturn is a lovely object to view with the eye alone. Binoculars will enhance its color, and even small telescopes will show you Saturn’s rings. Veteran observer Alan MacRobert at SkyandTelescope.com has written:

The rings of Saturn should be visible in even the smallest telescope at 25x [magnified by 25 times]. A good 3-inch scope at 50x [magnified by 50 times] can show them as a separate structure detached on all sides from the ball of the planet.

You want to see Saturn’s rings. We know you do! With the moon passing Saturn this week, it’s a good time to identify the planet with the eye alone. See the chart below:

The moon sweeps past Saturn on the nights of June 7 and 8, 2020. Read more.

See, on the chart above, how Saturn is near a brighter planet, Jupiter? These two planets will be near each other throughout 2020. Jupiter outshines all the stars, so its proximity to Saturn will make finding Saturn a breeze. And, before this year ends, Jupiter and Saturn will have a great conjunction?

Okay, got Saturn? It’ll be great fun to watch it and Jupiter throughout the rest of 2020. Now … about that telescope. One possibility is to start scouting out a star party near you, where amateur astronomers are set up to show you telescopic objects. Check the club map at NASA’s Night Sky Network to find star parties. Or try this list of astronomy clubs by state from the Astronomical League. Or call a local university or science museum and ask about star parties. Or maybe a neighbor, or friend, has a telescope stashed in a closet? More possibilities:

Astronomy Clubs Near Me & Organizations, from SkyandTelescope.com.

2018 Astronomy Club Directory, from Go-Astronomy.com.

Astronomy Clubs Near Me, from LoveTheNightSky.com.

Okay, so you can find Saturn in the sky, and you’ve found a star party to attend. Here are some things to think about before your Saturn ring-viewing session:

1. Telescope. Don’t expect to see the rings in binoculars. You really do need a telescope. A bigger telescope will show you more than a smaller telescope. Check out the contrast between the two photos below.

These images suggest how the ringed planet Saturn might look when seen through a telescope with an aperture 4 inches (100 mm) in diameter (top) and through a larger instrument with an 8-inch (200 mm) aperture (bottom). Image via SkyandTelescope.com/ NASA/ Hubble Space Telescope.

2. Tilt. Notice the tilt of the rings. As with so much in space (and on Earth), the appearance of Saturn’s rings from Earth is cyclical. In 2017, the north side of the rings opened up most widely (27 degrees), as seen from Earth. That’s the most open this face of the rings has been since since 1988. In 2020, we’re past the peak of the north ring face opening, but Saturn’s rings are still inclined at nearly 22 degrees from edge-on, still exhibiting their northern face. By the year 2025, the rings will appear edge-on as seen from Earth. At such times, because the rings are so thin, it’s possible to view Saturn through a telescope as if it has no rings at all! After that, we’ll begin to see the south side of Saturn’s rings and their openness will gradually increase to a maximum inclination of 27 degrees by May 2032.

The tilt of Saturn’s rings has a great impact on the planet’s overall brightness as seen from Earth. In years when Saturn’s rings are edge-on as seen from Earth (2009 and 2025), Saturn does appear considerably dimmer than in years when Saturn’s rings are maximally tilted toward Earth (2017 and 2032). These Saturn views were simulated with a computer program written by Tom Ruen. Image via Wikimedia Commons.

3. 3D. Ask yourself … do Saturn’s rings look three-dimensional? Again quoting Alan MacRobert at SkyandTelescope.com:

Saturn has a more three-dimensional appearance than any other object in the sky — at least that’s how it looks to me with a 6-inch ‘scope on a night of fine seeing.

4. Seeing. What was Alan talking about in that quote above when he mentioned seeing? Both amateur and professional astronomers talk about the night’s seeing, which affects how clearly and sharply you can see a telescopic image. Seeing isn’t a quality of the telescope; it’s a quality of the air above you. It’s the reason the stars twinkle more on some nights than others. When the air is particularly turbulent, astronomers say there’s bad seeing. The images at the telescope shimmy and dance. When the air is particularly still, astronomers say there’s good seeing. Seeing can shift from moment to moment, as parcels of air move above you. So, as you’re gazing at Saturn, stand as quietly as you can – for as long as you can – and just look. You’ll notice moments when the image suddenly comes into sharper focus.

Turbulent air makes for poor seeing. But the air above you can also “settle” suddenly. When viewing Saturn, wait for those moments. Image via AstronomyNotes.com.

5. Other things to think about. Once you get comfortable viewing Saturn – assuming you’re able to view it again and again, with a telescope of your own – you’ll begin to notice details in the rings. Today, thanks to spacecraft, we know that Saturn’s rings are incredibly detailed. But, as you stand at your telescope gazing upward, you might be thrilled to witness just one primary division in the rings, the Cassini Division between the A and B rings, named for its French discoverer Jean Cassini. Seeing this dark division is a good test of the night’s seeing and your telescope’s optical quality, and also of your own eyes’ ability to simply look and notice what you see. By the way, if you’re looking at the rings – which means you’re viewing Saturn through a telescope – look also for one or more of Saturn’s many moons, most notably Titan.

Have fun!

Alas, you won’t see Saturn look like this through a telescope. This is a spacecraft view, from Cassini in 2016, showing Saturn’s northern hemisphere. Image via NASA/ JPL-Caltech/ Space Science Institute.

Bottom line: In 2020, Saturn’s opposition – marking the middle of the best time of year to see it – comes on July 20. Here are some tips for beginners who want to see Saturn’s rings.

Read more … Viewing Saturn: Rings, Planet and Moons

Help EarthSky keep going! Please donate.

from EarthSky https://ift.tt/2Y9hEUV

Watch for Jupiter, Saturn and the moon

To see Jupiter and Saturn now, look outside from late night – when you’ll find them ascending in the east – until dawn. The late night on June 7, 2020 or early morning on June 8 are grand opportunities to identify them as the moon sweeps by. This chart shows the sky from 40 degrees N. latitude, 3-and-a-half hours after sunset. For your specific view, or a different time of night, try Stellarium. Chart via Guy Ottewell’s blog.

Originally printed at Guy Ottewell’s blog, Universal Workshop. Re-printed here with permission.

As Jupiter continues to catch up with Saturn – preparing for their once-in-20-years great conjunction in December 2020 – the waning moon comes by, this time passing 2.2° south of Jupiter on June 8 and 2.7° south of Saturn on June 9.

Those angular separations – or apparent separations on or sky’s dome – refer to the center of the moon; from our northern latitudes, the moon is pushed a bit south.

In my picture at top, the moon (at twice its real size) is where it is seen from the chosen U.S. location; but the arrows connecting moon positions are along the track it would take if viewed from the center of the Earth. The difference is the effect called parallax, an effect you can experience yourself when when you hold a finger in front of your nose, but look into the distance (you see two fingers, separated by parallax).

The grouping of the three luminaries – Jupiter, Saturn and the moon – will be tightest at 22h UTC, 17 hours after the time of the picture and in daylight for America. The planets and the moon’s center get to be within a circle of diameter 5.06 degrees, though that is as seen from Earth’s center (parallax makes it a bit wider).

For Saturn, we show its disk, exaggerated 150 times in size, so as to show the current attitude of its rings (their north face is open toward us).

On June 7, the moon will be two days past full, so the planets will be twinkles within its glare. The magnitudes of the moon, Jupiter, and Saturn are -12, -3, and 0.

As the night goes on, the scene will slant up to higher in the sky. And then, if your sky is clear and dark, the Milky Way will become visible.

But not Pluto! Notice it on the chart at top. Pluto is more than 1,000 times too faint to be viewed with the eye. Yet telescopic observers can use Jupiter to find Pluto this year. Read more: Jupiter gives us Pluto in 2020

Now note the area marked as solstice point on the chart at top. That is where the sun is at mid-winter, at its most southerly point on the ecliptic. These planets, and the moon when opposite to the summer sun, are nearly as far south as they can be in the sky.

The anti-sun, as I call it, is also not something that can be seen, except at a lunar eclipse, when Earth’s shadow becomes visible on the moon; but it is an interesting point to contemplate. See it on the chart at top? When at or near it, the moon is full and a planet is at opposition, or most nearly opposite the sun from Earth for that year. It divides the evening sky, to the right of it, from the morning sky, to the left.

Thus, by staying up late, you get a look into the morning sky, of which Jupiter and Saturn are the heralds.

Bottom line: Watch for the moon, Jupiter and Saturn around June 7, 2020. The moon is very bright now, so Jupiter and Saturn are specks in its glare. Jupiter is a brighter speck than Saturn.

Read more: Before 2020 ends, a great conjunction of Jupiter and Saturn

from EarthSky https://ift.tt/3dGzkPo

To see Jupiter and Saturn now, look outside from late night – when you’ll find them ascending in the east – until dawn. The late night on June 7, 2020 or early morning on June 8 are grand opportunities to identify them as the moon sweeps by. This chart shows the sky from 40 degrees N. latitude, 3-and-a-half hours after sunset. For your specific view, or a different time of night, try Stellarium. Chart via Guy Ottewell’s blog.

Originally printed at Guy Ottewell’s blog, Universal Workshop. Re-printed here with permission.

As Jupiter continues to catch up with Saturn – preparing for their once-in-20-years great conjunction in December 2020 – the waning moon comes by, this time passing 2.2° south of Jupiter on June 8 and 2.7° south of Saturn on June 9.

Those angular separations – or apparent separations on or sky’s dome – refer to the center of the moon; from our northern latitudes, the moon is pushed a bit south.

In my picture at top, the moon (at twice its real size) is where it is seen from the chosen U.S. location; but the arrows connecting moon positions are along the track it would take if viewed from the center of the Earth. The difference is the effect called parallax, an effect you can experience yourself when when you hold a finger in front of your nose, but look into the distance (you see two fingers, separated by parallax).

The grouping of the three luminaries – Jupiter, Saturn and the moon – will be tightest at 22h UTC, 17 hours after the time of the picture and in daylight for America. The planets and the moon’s center get to be within a circle of diameter 5.06 degrees, though that is as seen from Earth’s center (parallax makes it a bit wider).

For Saturn, we show its disk, exaggerated 150 times in size, so as to show the current attitude of its rings (their north face is open toward us).

On June 7, the moon will be two days past full, so the planets will be twinkles within its glare. The magnitudes of the moon, Jupiter, and Saturn are -12, -3, and 0.

As the night goes on, the scene will slant up to higher in the sky. And then, if your sky is clear and dark, the Milky Way will become visible.

But not Pluto! Notice it on the chart at top. Pluto is more than 1,000 times too faint to be viewed with the eye. Yet telescopic observers can use Jupiter to find Pluto this year. Read more: Jupiter gives us Pluto in 2020

Now note the area marked as solstice point on the chart at top. That is where the sun is at mid-winter, at its most southerly point on the ecliptic. These planets, and the moon when opposite to the summer sun, are nearly as far south as they can be in the sky.

The anti-sun, as I call it, is also not something that can be seen, except at a lunar eclipse, when Earth’s shadow becomes visible on the moon; but it is an interesting point to contemplate. See it on the chart at top? When at or near it, the moon is full and a planet is at opposition, or most nearly opposite the sun from Earth for that year. It divides the evening sky, to the right of it, from the morning sky, to the left.

Thus, by staying up late, you get a look into the morning sky, of which Jupiter and Saturn are the heralds.

Bottom line: Watch for the moon, Jupiter and Saturn around June 7, 2020. The moon is very bright now, so Jupiter and Saturn are specks in its glare. Jupiter is a brighter speck than Saturn.

Read more: Before 2020 ends, a great conjunction of Jupiter and Saturn

from EarthSky https://ift.tt/3dGzkPo

Jupiter, Saturn, moon on June 6-8, plus a word about the daytime moon

If you stay up late on the nights of June 6, 7 and 8, 2020, you can glimpse the moon with the bright planets Jupiter and Saturn, ascending in the east. Or see them before daybreak.

Among all the wonderful planet-viewing we’re having in 2020, Jupiter and Saturn hold their own, excitement-wise, by being near one another on the sky’s dome throughout this year. By 2020’s end, they’ll undergo a once-in-20-years great conjunction. This month, and for some months to come, Saturn will closely follow Jupiter westward across the sky. Watch for them in June from mid-to-late evening until dawn. Although Saturn is easily as bright as a 1st-magnitude star, the ringed planet pales next the the king planet Jupiter, which outshines Saturn by some 15 times.

Read more: Before 2020 ends, a great conjunction of Jupiter and Saturn

Try Stellarium for your specific view

After Jupiter and Saturn fade at sunup, look for a daytime moon to remain. No matter where you are on Earth, look generally westward after sunrise to see the moon in a blue daytime sky, assuming your sky is clear.

Are you an early riser? Then enjoy seeing the moon, Jupiter and Saturn higher up in the predawn/dawn sky. Although not visible, we show the dwarf planet Pluto because it’s close to Jupiter on the sky’s dome thruoghout the year 2020. Read more.

Why can you see the moon in the daytime now? The full moon – and partial penumbral eclipse – happened on the night of June 5-6, 2020, for the world’s Eastern Hemisphere. In the days after full moon, the moon is officially in a waning gibbous phase, rising in the east after nightfall and setting in a westward direction shortly after sunrise.

If you look for the moon at the same time every morning, you’ll see this week’s waning moon appearing higher and higher in the western sky each early morning, for several days. To understand why, think about where the sun is in early morning. A full moon is opposite the sun, in the west when the sun is in the east. Except now it’s after full moon. The moon is moving in its orbit around Earth – moving toward the east, as it always does – drawing closer and closer to the Earth-sun line.

By June 13, 2020, the moon will be at the last quarter phase – rising around midnight, southward around dawn. Then the moon will turn new on June 21, 2020, to showcase an annular eclipse of the sun. Two weeks after that, there will be a third eclipse – another penumbral eclipse of the moon – on the night of July 4-5. We won’t have three eclipses in one eclipse season again until the year 2029.

Read more: What is an eclipse season?

It still looks almost full, but the moon was just slightly past full. And so it was a waning gibbous moon that Peter Lowenstein caught on the morning of January 13, 2017 in Mutare, Zimbabwe.

People love to see the daytime moon. They wonder about it, and ask about it. Once, a reader in Kansas City wrote in with the name children’s moon to describe a moon visible during the day. She said this name stemmed from the idea that children can’t stay up at night late enough to see the moon when it appears only in darkness.

That story prompted another reader to send in an alternate version for the origin of the name children’s moon. She wrote:

I heard a daytime moon was called a ‘children’s moon’ because their eyes were sharp enough to pick it out, where the old folks, with fading vision, could not tell it from the clouds.

Can you see the daytime moon in the next few mornings?

July 29, 2018, daytime moon – caught from a rooftop in New York City – via our friend Ben Orlove.

Here’s another July daytime moon – from the year 2017 – from Jeff Hagan in Yakima, Washington. He wrote: “I woke up early and stepped onto the deck at our house in Yakima to check the weather. I was just in time to watch the full moon set over Mt. Adams, a 12,300-foot glaciated volcano in the Cascade Mountains. The moon appeared to be rolling down the north ridge of the mountain.”

Bottom line: If you stay up late on the nights of June 6, 7 and 8, 2020, you can glimpse the moon with the bright planets Jupiter and Saturn, ascending in the east. Or see them before daybreak.

A planisphere is virtually indispensable for beginning stargazers. Order your EarthSky planisphere today.

Four keys to understanding moon phases

from EarthSky https://ift.tt/2YWMpNl

If you stay up late on the nights of June 6, 7 and 8, 2020, you can glimpse the moon with the bright planets Jupiter and Saturn, ascending in the east. Or see them before daybreak.

Among all the wonderful planet-viewing we’re having in 2020, Jupiter and Saturn hold their own, excitement-wise, by being near one another on the sky’s dome throughout this year. By 2020’s end, they’ll undergo a once-in-20-years great conjunction. This month, and for some months to come, Saturn will closely follow Jupiter westward across the sky. Watch for them in June from mid-to-late evening until dawn. Although Saturn is easily as bright as a 1st-magnitude star, the ringed planet pales next the the king planet Jupiter, which outshines Saturn by some 15 times.

Read more: Before 2020 ends, a great conjunction of Jupiter and Saturn

Try Stellarium for your specific view

After Jupiter and Saturn fade at sunup, look for a daytime moon to remain. No matter where you are on Earth, look generally westward after sunrise to see the moon in a blue daytime sky, assuming your sky is clear.

Are you an early riser? Then enjoy seeing the moon, Jupiter and Saturn higher up in the predawn/dawn sky. Although not visible, we show the dwarf planet Pluto because it’s close to Jupiter on the sky’s dome thruoghout the year 2020. Read more.

Why can you see the moon in the daytime now? The full moon – and partial penumbral eclipse – happened on the night of June 5-6, 2020, for the world’s Eastern Hemisphere. In the days after full moon, the moon is officially in a waning gibbous phase, rising in the east after nightfall and setting in a westward direction shortly after sunrise.

If you look for the moon at the same time every morning, you’ll see this week’s waning moon appearing higher and higher in the western sky each early morning, for several days. To understand why, think about where the sun is in early morning. A full moon is opposite the sun, in the west when the sun is in the east. Except now it’s after full moon. The moon is moving in its orbit around Earth – moving toward the east, as it always does – drawing closer and closer to the Earth-sun line.

By June 13, 2020, the moon will be at the last quarter phase – rising around midnight, southward around dawn. Then the moon will turn new on June 21, 2020, to showcase an annular eclipse of the sun. Two weeks after that, there will be a third eclipse – another penumbral eclipse of the moon – on the night of July 4-5. We won’t have three eclipses in one eclipse season again until the year 2029.

Read more: What is an eclipse season?

It still looks almost full, but the moon was just slightly past full. And so it was a waning gibbous moon that Peter Lowenstein caught on the morning of January 13, 2017 in Mutare, Zimbabwe.

People love to see the daytime moon. They wonder about it, and ask about it. Once, a reader in Kansas City wrote in with the name children’s moon to describe a moon visible during the day. She said this name stemmed from the idea that children can’t stay up at night late enough to see the moon when it appears only in darkness.

That story prompted another reader to send in an alternate version for the origin of the name children’s moon. She wrote:

I heard a daytime moon was called a ‘children’s moon’ because their eyes were sharp enough to pick it out, where the old folks, with fading vision, could not tell it from the clouds.

Can you see the daytime moon in the next few mornings?

July 29, 2018, daytime moon – caught from a rooftop in New York City – via our friend Ben Orlove.

Here’s another July daytime moon – from the year 2017 – from Jeff Hagan in Yakima, Washington. He wrote: “I woke up early and stepped onto the deck at our house in Yakima to check the weather. I was just in time to watch the full moon set over Mt. Adams, a 12,300-foot glaciated volcano in the Cascade Mountains. The moon appeared to be rolling down the north ridge of the mountain.”

Bottom line: If you stay up late on the nights of June 6, 7 and 8, 2020, you can glimpse the moon with the bright planets Jupiter and Saturn, ascending in the east. Or see them before daybreak.

A planisphere is virtually indispensable for beginning stargazers. Order your EarthSky planisphere today.

Four keys to understanding moon phases

from EarthSky https://ift.tt/2YWMpNl

News digest – prostate cancer, COVID-19 trials, breast cancer genes and street lamps?

With news about the coronavirus pandemic developing daily, we want to make sure everyone affected by cancer gets the information they need during this time. 

We’re pulling together the latest government and NHS health updates from across the UK in a separate blog post, which we’re updating regularly. 

Prostate cancer most commonly diagnosed cancer in the UK

New analysis from Prostate Cancer UK suggests that prostate cancer has overtaken breast cancer as the most commonly diagnosed cancer in the UK. Though the numbers aren’t yet the full picture, the charity’s research finds that 57,192 new prostate cancer cases were diagnosed in the UK in 2018, just ahead of the 57,153 breast cancer cases that were diagnosed in the same year. The increasing number of new prostate cancer cases has been linked to increased awareness and earlier diagnosis. But more work is needed to develop tests that can differentiate between aggressive cancers and cancers that may never cause harm in an person’s lifetime. Find out more at The Guardian.

Prostate cancer blood test could help to tailor treatment 

Researchers at The Institute of Cancer Research (ICR) and The Royal Marsden NHS Foundation Trust have developed a new blood test that could help to predict how well patients with advanced prostate cancer will respond to treatment. The test could help clinicians to make more effective treatment decisions for people with advanced prostate cancer. The ICR and Royal Marsden are now looking to incorporate the test into other clinical trials to assess its benefits. Read more at Science Focus.

Cancer cells trigger inflammation to hide from viruses 

An international study led by a team at the Francis Crick Institute has helped researchers to understand why using viruses to kill cancer cells is only effective in a small number of people. The team found that a group of cells, known as cancer-associated fibroblasts (CAFs), cause inflammation in surrounding tissue when they come into contact with cancer cells. Researchers think this inflammation makes it difficult for cancer-killing viruses to enter cancer cells, limiting the effectiveness of virus-based cancer treatments. The team hopes that the study provides an ‘early step’ to improving the effectiveness of oncolytic virus treatments. Find out about the study at the Crick and News Atlas.

Repurposed drug tested for COVID-19, thanks to Cancer Research UK know-how 

Together with our partners, we’ve launched a clinical trial to test if a drug used to treat inflammation in the pancreas can treat people with COVID-19. With COVID-19 delaying cancer research and treatment, our researchers are using their expertise to help tackle the disease and get cancer services back on track, as our press release explains. 

Turning off a ‘key’ gene disrupts development and spread of triple-negative breast cancer in mice 

Researchers from Tulane University have found that ‘switching off’ a gene linked to triple triple negative breast cancer – TRAF3IP2 – can disrupt cancer growth and spread in mice. The researchers are now looking to get approval to start clinical trials . Read more about the discovery at Biospace. 

And finally…

Researchers at the National Cancer Institute in the United States have suggested that exposure to light at night from street lamps might be linked to an up to 10% increased risk of developing breast cancer after menopause. The study examined cases of breast cancer among 186,981 post-menopausal women over a 16-year period. Its findings suggest that women exposed to the highest levels of outdoor light at night had a ten percent higher chance of developing breast cancer during the follow up, compared to women with the lowest exposure. But despite the headlines, the findings don’t mean that street lamps cause breast cancer, and more research is needed to understand any connection. The Sun has this one.

Jamie Hamilton is a media and communication analyst at Cancer Research UK 

from Cancer Research UK – Science blog https://ift.tt/3f01chB

With news about the coronavirus pandemic developing daily, we want to make sure everyone affected by cancer gets the information they need during this time. 

We’re pulling together the latest government and NHS health updates from across the UK in a separate blog post, which we’re updating regularly. 

Prostate cancer most commonly diagnosed cancer in the UK

New analysis from Prostate Cancer UK suggests that prostate cancer has overtaken breast cancer as the most commonly diagnosed cancer in the UK. Though the numbers aren’t yet the full picture, the charity’s research finds that 57,192 new prostate cancer cases were diagnosed in the UK in 2018, just ahead of the 57,153 breast cancer cases that were diagnosed in the same year. The increasing number of new prostate cancer cases has been linked to increased awareness and earlier diagnosis. But more work is needed to develop tests that can differentiate between aggressive cancers and cancers that may never cause harm in an person’s lifetime. Find out more at The Guardian.

Prostate cancer blood test could help to tailor treatment 

Researchers at The Institute of Cancer Research (ICR) and The Royal Marsden NHS Foundation Trust have developed a new blood test that could help to predict how well patients with advanced prostate cancer will respond to treatment. The test could help clinicians to make more effective treatment decisions for people with advanced prostate cancer. The ICR and Royal Marsden are now looking to incorporate the test into other clinical trials to assess its benefits. Read more at Science Focus.

Cancer cells trigger inflammation to hide from viruses 

An international study led by a team at the Francis Crick Institute has helped researchers to understand why using viruses to kill cancer cells is only effective in a small number of people. The team found that a group of cells, known as cancer-associated fibroblasts (CAFs), cause inflammation in surrounding tissue when they come into contact with cancer cells. Researchers think this inflammation makes it difficult for cancer-killing viruses to enter cancer cells, limiting the effectiveness of virus-based cancer treatments. The team hopes that the study provides an ‘early step’ to improving the effectiveness of oncolytic virus treatments. Find out about the study at the Crick and News Atlas.

Repurposed drug tested for COVID-19, thanks to Cancer Research UK know-how 

Together with our partners, we’ve launched a clinical trial to test if a drug used to treat inflammation in the pancreas can treat people with COVID-19. With COVID-19 delaying cancer research and treatment, our researchers are using their expertise to help tackle the disease and get cancer services back on track, as our press release explains. 

Turning off a ‘key’ gene disrupts development and spread of triple-negative breast cancer in mice 

Researchers from Tulane University have found that ‘switching off’ a gene linked to triple triple negative breast cancer – TRAF3IP2 – can disrupt cancer growth and spread in mice. The researchers are now looking to get approval to start clinical trials . Read more about the discovery at Biospace. 

And finally…

Researchers at the National Cancer Institute in the United States have suggested that exposure to light at night from street lamps might be linked to an up to 10% increased risk of developing breast cancer after menopause. The study examined cases of breast cancer among 186,981 post-menopausal women over a 16-year period. Its findings suggest that women exposed to the highest levels of outdoor light at night had a ten percent higher chance of developing breast cancer during the follow up, compared to women with the lowest exposure. But despite the headlines, the findings don’t mean that street lamps cause breast cancer, and more research is needed to understand any connection. The Sun has this one.

Jamie Hamilton is a media and communication analyst at Cancer Research UK 

from Cancer Research UK – Science blog https://ift.tt/3f01chB

Did ancient Mars have rings?

Artist’s concept of the red planet Mars with rings. Image via Kevin Gill on Flickr/ CC by 2.0.

Ring systems are common in our solar system. Jupiter, Saturn, Uranus and Neptune all have rings. None of the smaller rocky planets have them, but is it possible that some of them could have had rings in the past? On June 2, 2020, scientists from the SETI Institute and Purdue University announced evidence suggesting that Mars used to have its own rings a few billion years ago. The findings would help explain why Mars’ smallest moon, Deimos, has an unusually tilted orbit.

The researchers published the new peer-reviewed paper in Astrophysical Journal Letters on June 1, 2020. The research was also presented at the 236th Meeting of the American Astronomical Society (AAS 236), held virtually this week (June 1-3, 2020) due to COVID-19.

While the orbits of both small moons, Phobos and Deimos, lie almost in the same plane as Mars’ equator – suggesting they formed at the same time as Mars – Deimos’ orbit is tilted by about 2 degrees. This tilt was an unusual and unexplained finding. It was also considered to be not all that significant in terms of Mars science.

Now it seems that, all along, that small anomaly – the 2-degree tilt of Deimos’ orbit with respect to Mars’ equator – held a clue to something very interesting about the red planet’s past … that Mars used to have rings!

Mars’ smallest moon, Deimos, as seen by the Mars Reconnaissance Orbiter spacecraft on February 21, 2009. The tilted orbit of the moon hints at ancient ring system around Mars. Image via NASA/ JPL-Caltech/ University of Arizona/ SETI Institute.

Lead author Matija Cuk at the SETI Institute explained in a statement:

The fact that Deimos’s orbit is not exactly in plane with Mars’s equator was considered unimportant, and nobody cared to try to explain it. But once we had a big new idea and we looked at it with new eyes, Deimos’s orbital tilt revealed its big secret.

Three years ago, scientists suggested that the larger of Mars’ two tiny moons – Phobos – might periodically create a ring system for Mars. In that scenario, Mars has had a series of rings, appearing in cycles over billions of years, and it will have rings again in the future. It happens because – for example, at present – Phobos is slowly orbiting closer and closer to Mars. Eventually, Mars’ gravity will rip Photos apart and the fabric of the moon’s body will form a ring. Later, the material in the ring will coalesce to form a moon again. The researchers think that this has happened many times over Mars’ history. The new paper on a Mars ring from the other moon, Deimos, speaks to this alternate theory:

Alternatively, Hesselbrock & Minton (2017) propose that Phobos is only the latest product of a repeating ring-satellite cycle at Mars, with each successive inner satellite being less massive than the preceding one. In the ring-satellite cycle model, satellites form from the outer edge of the ring, and then migrate outward through gravitational interaction with the ring. The ring loses mass to the planet at its inner edge, and once the ring is sufficiently depleted the satellite migrates inward due to tides.

How does this earlier idea relate to the new scenario involving Deimos?

According to the researchers, a newborn moon would move away from both the ring and Mars, heading in the opposite direction from Phobos, or any inwardly-migrating moon. An outwardly-migrating moon, just outside of the rings, could come to experience an orbital resonance – a situation where two orbiting bodies are exerting a regular, periodic gravitational influence on each other – so that the orbital period of Deimos comes to be precisely three times that of the other moon. The researchers’ statement explained:

These orbital resonances are picky but predictable … We can tell that only an outward-moving moon could have strongly affected Deimos, which means that Mars must have had a ring pushing the inner moon outward. Cuk and collaborators deduce that this moon may have been 20 times as massive as Phobos, and may have been its ‘grandparent’ existing just over 3 billion years ago … [that] was followed by two more ring-moon cycles, with the latest moon being Phobos.

Saturn, of course, has the most well-known rings in the solar system, as seen here by the Cassini spacecraft. Image via NASA/ JPL-Caltech.

The formation of Phobos probably happened about 3 1/2 billion years ago, Cuk told ScienceAlert:

Something like 3.5 billion years ago is our best bet. That agrees beautifully with Hesselbrock and Minton’s calculation on when Mars had an inner moon with 20 times the mass of Phobos. Once the ring was gone, the moon also started falling because of Martian tides (just like Phobos). Once it was too close to Mars, tidal forces would pull it apart into a new ring, and the cycle would repeat, probably twice, to get to Phobos that we see.

It’s known that Phobos is much younger than Deimos – perhaps as young as about 200 million years old in contrast to a few billion years old for Deimos – which would fit this scenario.

The findings are fascinating since they imply that Mars has had at least one prominent ring, and probably more, during its lifetime. This would mean that smaller rocky planets can also have rings, although none of those in our current solar system do.

On the other hand, scientists know that the ring process must be a common one in our solar system.

Artist’s concept of asteroid Chariklo, which, in 2014, was the first object in the solar system smaller than the gas or ice giant planets found to have rings. Image via ESO.

They know that because Jupiter, Saturn, Uranus and Neptune all are known to have rings. And, in 2014, astronomers discovered an asteroid – named Chariklo – with two dense and narrow rings. This was the first time that rings were found around any solar system object smaller than the gas or ice giant planets. Chariklo is a member of a group of asteroids called Centaurs that orbit between Jupiter and Neptune. Uffe Gråe Jørgensen at Niels Bohr Institute, University of Copenhagen in Denmark, said of Chariklo:

For me, it was quite amazing to realize that we were able not only to detect a ring system, but also pinpoint that it consists of two clearly distinct rings. I try to imagine how it would be to stand on the surface of this icy object – small enough that a fast sports car could reach escape velocity and drive off into space – and stare up at a 20-kilometer (12-mile) wide ring system 1,000 times closer than the moon.

In 2017, a ring was also discovered around the asteroid-like dwarf planet Haumea, which orbits beyond Neptune in the Kuiper Belt.

Matija Cuk at the SETI Institute, lead author of the new study. Image via SETI Institute.

The Japanese space agency JAXA is planning to send a new mission to Phobos in 2024, which will collect samples for return to Earth. This will hopefully provide more clues about Mars’ rings and the previous larger moon that Phobos came from. Cuk said:

I do theoretical calculations for a living, and they are good, but getting them tested against the real world now and then is even better.

It would be really cool if we could go back in time and see the rings of Mars as they once were. But, we can still learn about them by studying the clues left behind in the planet’s two remaining little moons, Deimos and Phobos.

Bottom line: A new research study of Mars’ smallest moon Deimos suggests that the planet used to have a ring or rings a few billion years ago.

Source: Evidence for a Past Martian Ring from the Orbital Inclination of Deimos

Via SETI Institute

from EarthSky https://ift.tt/30iqV0C

Artist’s concept of the red planet Mars with rings. Image via Kevin Gill on Flickr/ CC by 2.0.

Ring systems are common in our solar system. Jupiter, Saturn, Uranus and Neptune all have rings. None of the smaller rocky planets have them, but is it possible that some of them could have had rings in the past? On June 2, 2020, scientists from the SETI Institute and Purdue University announced evidence suggesting that Mars used to have its own rings a few billion years ago. The findings would help explain why Mars’ smallest moon, Deimos, has an unusually tilted orbit.

The researchers published the new peer-reviewed paper in Astrophysical Journal Letters on June 1, 2020. The research was also presented at the 236th Meeting of the American Astronomical Society (AAS 236), held virtually this week (June 1-3, 2020) due to COVID-19.

While the orbits of both small moons, Phobos and Deimos, lie almost in the same plane as Mars’ equator – suggesting they formed at the same time as Mars – Deimos’ orbit is tilted by about 2 degrees. This tilt was an unusual and unexplained finding. It was also considered to be not all that significant in terms of Mars science.

Now it seems that, all along, that small anomaly – the 2-degree tilt of Deimos’ orbit with respect to Mars’ equator – held a clue to something very interesting about the red planet’s past … that Mars used to have rings!

Mars’ smallest moon, Deimos, as seen by the Mars Reconnaissance Orbiter spacecraft on February 21, 2009. The tilted orbit of the moon hints at ancient ring system around Mars. Image via NASA/ JPL-Caltech/ University of Arizona/ SETI Institute.

Lead author Matija Cuk at the SETI Institute explained in a statement:

The fact that Deimos’s orbit is not exactly in plane with Mars’s equator was considered unimportant, and nobody cared to try to explain it. But once we had a big new idea and we looked at it with new eyes, Deimos’s orbital tilt revealed its big secret.

Three years ago, scientists suggested that the larger of Mars’ two tiny moons – Phobos – might periodically create a ring system for Mars. In that scenario, Mars has had a series of rings, appearing in cycles over billions of years, and it will have rings again in the future. It happens because – for example, at present – Phobos is slowly orbiting closer and closer to Mars. Eventually, Mars’ gravity will rip Photos apart and the fabric of the moon’s body will form a ring. Later, the material in the ring will coalesce to form a moon again. The researchers think that this has happened many times over Mars’ history. The new paper on a Mars ring from the other moon, Deimos, speaks to this alternate theory:

Alternatively, Hesselbrock & Minton (2017) propose that Phobos is only the latest product of a repeating ring-satellite cycle at Mars, with each successive inner satellite being less massive than the preceding one. In the ring-satellite cycle model, satellites form from the outer edge of the ring, and then migrate outward through gravitational interaction with the ring. The ring loses mass to the planet at its inner edge, and once the ring is sufficiently depleted the satellite migrates inward due to tides.

How does this earlier idea relate to the new scenario involving Deimos?

According to the researchers, a newborn moon would move away from both the ring and Mars, heading in the opposite direction from Phobos, or any inwardly-migrating moon. An outwardly-migrating moon, just outside of the rings, could come to experience an orbital resonance – a situation where two orbiting bodies are exerting a regular, periodic gravitational influence on each other – so that the orbital period of Deimos comes to be precisely three times that of the other moon. The researchers’ statement explained:

These orbital resonances are picky but predictable … We can tell that only an outward-moving moon could have strongly affected Deimos, which means that Mars must have had a ring pushing the inner moon outward. Cuk and collaborators deduce that this moon may have been 20 times as massive as Phobos, and may have been its ‘grandparent’ existing just over 3 billion years ago … [that] was followed by two more ring-moon cycles, with the latest moon being Phobos.

Saturn, of course, has the most well-known rings in the solar system, as seen here by the Cassini spacecraft. Image via NASA/ JPL-Caltech.

The formation of Phobos probably happened about 3 1/2 billion years ago, Cuk told ScienceAlert:

Something like 3.5 billion years ago is our best bet. That agrees beautifully with Hesselbrock and Minton’s calculation on when Mars had an inner moon with 20 times the mass of Phobos. Once the ring was gone, the moon also started falling because of Martian tides (just like Phobos). Once it was too close to Mars, tidal forces would pull it apart into a new ring, and the cycle would repeat, probably twice, to get to Phobos that we see.

It’s known that Phobos is much younger than Deimos – perhaps as young as about 200 million years old in contrast to a few billion years old for Deimos – which would fit this scenario.

The findings are fascinating since they imply that Mars has had at least one prominent ring, and probably more, during its lifetime. This would mean that smaller rocky planets can also have rings, although none of those in our current solar system do.

On the other hand, scientists know that the ring process must be a common one in our solar system.

Artist’s concept of asteroid Chariklo, which, in 2014, was the first object in the solar system smaller than the gas or ice giant planets found to have rings. Image via ESO.

They know that because Jupiter, Saturn, Uranus and Neptune all are known to have rings. And, in 2014, astronomers discovered an asteroid – named Chariklo – with two dense and narrow rings. This was the first time that rings were found around any solar system object smaller than the gas or ice giant planets. Chariklo is a member of a group of asteroids called Centaurs that orbit between Jupiter and Neptune. Uffe Gråe Jørgensen at Niels Bohr Institute, University of Copenhagen in Denmark, said of Chariklo:

For me, it was quite amazing to realize that we were able not only to detect a ring system, but also pinpoint that it consists of two clearly distinct rings. I try to imagine how it would be to stand on the surface of this icy object – small enough that a fast sports car could reach escape velocity and drive off into space – and stare up at a 20-kilometer (12-mile) wide ring system 1,000 times closer than the moon.

In 2017, a ring was also discovered around the asteroid-like dwarf planet Haumea, which orbits beyond Neptune in the Kuiper Belt.

Matija Cuk at the SETI Institute, lead author of the new study. Image via SETI Institute.

The Japanese space agency JAXA is planning to send a new mission to Phobos in 2024, which will collect samples for return to Earth. This will hopefully provide more clues about Mars’ rings and the previous larger moon that Phobos came from. Cuk said:

I do theoretical calculations for a living, and they are good, but getting them tested against the real world now and then is even better.

It would be really cool if we could go back in time and see the rings of Mars as they once were. But, we can still learn about them by studying the clues left behind in the planet’s two remaining little moons, Deimos and Phobos.

Bottom line: A new research study of Mars’ smallest moon Deimos suggests that the planet used to have a ring or rings a few billion years ago.

Source: Evidence for a Past Martian Ring from the Orbital Inclination of Deimos

Via SETI Institute

from EarthSky https://ift.tt/30iqV0C