Are December’s solstice and January’s perihelion related?

Earth and sun via ISS Expedition 13/ NASA.

Earth comes closest to the sun on January 3, 2018 at around 5:35 UTC; translate to your time zone. This event is called Earth’s perihelion. Meanwhile, the December solstice took place on December 21, 2017. At perihelion in January, Earth swings to within about 91 million miles (147 million km) of the sun. That’s in contrast to six months from now, when we’ll be about 94 million miles (152 million km) from the sun. At the December solstice, Earth’s Southern Hemisphere is tilted most toward the sun; it’s the height of summer in that hemisphere. Are the December solstice and January perihelion related? No. It’s just a coincidence that they come so close together.

The date of Earth’s perihelion drifts as the centuries pass. These two astronomical events are separated by about two weeks for us. But they were closer a few centuries ago – and in fact happened at the same time in 1246 AD.

As the centuries continue to pass, these events will drift even farther apart. On the average, one revolution of the Earth relative to perihelion is about 25 minutes longer than one revolution relative to the December solstice. Perihelion advances one full calendar date every 60 or so years.

Earth’s perihelion – or closest point to the sun – will happen at the same time as the March equinox in about 6430 AD.

Bottom line: Earth’s December solstice and January perihelion are not related.

Earth closest to the sun on January 2-3, 2018

Everything you need to know: December solstice

Why does the New Year begin on January 1?

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Earth and sun via ISS Expedition 13/ NASA.

Earth comes closest to the sun on January 3, 2018 at around 5:35 UTC; translate to your time zone. This event is called Earth’s perihelion. Meanwhile, the December solstice took place on December 21, 2017. At perihelion in January, Earth swings to within about 91 million miles (147 million km) of the sun. That’s in contrast to six months from now, when we’ll be about 94 million miles (152 million km) from the sun. At the December solstice, Earth’s Southern Hemisphere is tilted most toward the sun; it’s the height of summer in that hemisphere. Are the December solstice and January perihelion related? No. It’s just a coincidence that they come so close together.

The date of Earth’s perihelion drifts as the centuries pass. These two astronomical events are separated by about two weeks for us. But they were closer a few centuries ago – and in fact happened at the same time in 1246 AD.

As the centuries continue to pass, these events will drift even farther apart. On the average, one revolution of the Earth relative to perihelion is about 25 minutes longer than one revolution relative to the December solstice. Perihelion advances one full calendar date every 60 or so years.

Earth’s perihelion – or closest point to the sun – will happen at the same time as the March equinox in about 6430 AD.

Bottom line: Earth’s December solstice and January perihelion are not related.

Earth closest to the sun on January 2-3, 2018

Everything you need to know: December solstice

Why does the New Year begin on January 1?

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Earth closest to sun on January 2-3

Cartoon above via Sara Zimmerman at Unearthed Comics.

Tonight – January 2, 2018 – we reach Earth’s closest point to the sun for this entire year at 11:35 p.m. CST (central U.S.). It’ll be the morning of January 3 for Europe and Africa … later in the day January 3 for the rest of the world (January 3 at 5:35 UTC; translate to your time zone). Astronomers call this special point in our orbit perihelion, from the Greek roots peri meaning near and helios meaning sun.

Source: Fred Espenak’s Earth at perihelion and aphelion, 2001 to 2100

On January 3, 2018, Earth at its closest point swings to within 91,401,983 miles (147,097,233 km) of the sun. That’s in contrast to six months from now, when the Earth reaches aphelion – its most distant point – on July 6, 2018. Then we’ll be 94,507,803 miles (152,095,566 km) from the sun.

In other words, Earth is about 3 million miles (5 million km) closer to the sun in early January than it is in early July. That’s always the case. Earth is closest to the sun every year in early January, when it’s winter for the Northern Hemisphere.

We’re farthest away from the sun in early July, during our Northern Hemisphere summer.

Image via NASA

So you see there’s not a huge distance difference between perihelion and aphelion. Earth’s orbit is very nearly circular. Thus it’s not our distance from the sun – but instead the tilt of our world’s axis – that creates winter and summer on Earth.

In winter, your part of Earth is tilted away from the sun. In summer, your part of Earth is tilted toward the sun. The day of maximum tilt toward or away from the sun is the December or June solstice.

Though not responsible for the seasons, Earth’s closest and farthest points to the sun do affect seasonal lengths. When the Earth comes closest to the sun for the year, as around now, our world is moving fastest in orbit around the sun. Earth is rushing along now at almost 19 miles per second (30.3 km/sec) – moving about a kilometer per second faster than when Earth is farthest from the sun in early July. Thus the Northern Hemisphere winter and – simultaneously – Southern Hemisphere summer are the shortest seasons as Earth rushes from the solstice in December to the equinox in March.

In the Northern Hemisphere, the summer season (June solstice to September equinox) lasts nearly 5 days longer than our winter season. And, of course, the corresponding seasons in the Southern Hemisphere are opposite. Southern Hemisphere winter is nearly 5 days longer than Southern Hemisphere summer.

It’s all due to the shape of Earth’s orbit. The shape is an ellipse, like a circle someone sat down on and squashed. The elliptical shape of Earth’s orbit causes the variation in the length of the seasons – and brings us closest to the sun in January.

Image Credit: Dna-webmaster

Bottom line: In 2018, Earth’s closest point to the sun – called its perihelion – comes on January 3 at 5:35 Universal Time (on January 2 at 11:35 p.m. CST).

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Are the December solstice and January perihelion related?

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Cartoon above via Sara Zimmerman at Unearthed Comics.

Tonight – January 2, 2018 – we reach Earth’s closest point to the sun for this entire year at 11:35 p.m. CST (central U.S.). It’ll be the morning of January 3 for Europe and Africa … later in the day January 3 for the rest of the world (January 3 at 5:35 UTC; translate to your time zone). Astronomers call this special point in our orbit perihelion, from the Greek roots peri meaning near and helios meaning sun.

Source: Fred Espenak’s Earth at perihelion and aphelion, 2001 to 2100

On January 3, 2018, Earth at its closest point swings to within 91,401,983 miles (147,097,233 km) of the sun. That’s in contrast to six months from now, when the Earth reaches aphelion – its most distant point – on July 6, 2018. Then we’ll be 94,507,803 miles (152,095,566 km) from the sun.

In other words, Earth is about 3 million miles (5 million km) closer to the sun in early January than it is in early July. That’s always the case. Earth is closest to the sun every year in early January, when it’s winter for the Northern Hemisphere.

We’re farthest away from the sun in early July, during our Northern Hemisphere summer.

Image via NASA

So you see there’s not a huge distance difference between perihelion and aphelion. Earth’s orbit is very nearly circular. Thus it’s not our distance from the sun – but instead the tilt of our world’s axis – that creates winter and summer on Earth.

In winter, your part of Earth is tilted away from the sun. In summer, your part of Earth is tilted toward the sun. The day of maximum tilt toward or away from the sun is the December or June solstice.

Though not responsible for the seasons, Earth’s closest and farthest points to the sun do affect seasonal lengths. When the Earth comes closest to the sun for the year, as around now, our world is moving fastest in orbit around the sun. Earth is rushing along now at almost 19 miles per second (30.3 km/sec) – moving about a kilometer per second faster than when Earth is farthest from the sun in early July. Thus the Northern Hemisphere winter and – simultaneously – Southern Hemisphere summer are the shortest seasons as Earth rushes from the solstice in December to the equinox in March.

In the Northern Hemisphere, the summer season (June solstice to September equinox) lasts nearly 5 days longer than our winter season. And, of course, the corresponding seasons in the Southern Hemisphere are opposite. Southern Hemisphere winter is nearly 5 days longer than Southern Hemisphere summer.

It’s all due to the shape of Earth’s orbit. The shape is an ellipse, like a circle someone sat down on and squashed. The elliptical shape of Earth’s orbit causes the variation in the length of the seasons – and brings us closest to the sun in January.

Image Credit: Dna-webmaster

Bottom line: In 2018, Earth’s closest point to the sun – called its perihelion – comes on January 3 at 5:35 Universal Time (on January 2 at 11:35 p.m. CST).

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

Are the December solstice and January perihelion related?

from EarthSky http://ift.tt/S3BOw5

January guide to the bright planets

Three bright planets and two bright stars adorn the morning sky in early January 2018. (Saturn appears later in the month.) An imaginary line drawn from the star Spica through the planets Jupiter and Mars helps you to locate Mercury near the horizon. Binoculars may be helpful. Click here for a recommended almanac that’ll give you Mercury’s rising time in your sky.

Four of the five bright planets – Mercury, Mars, Jupiter and Saturn – reside exclusively in the morning sky, before sunup, in January 2018. Mars and Jupiter are easy. They light up the predawn hours all month long and are in conjunction on January 7. Mercury is better seen in the first half of the month whereas Saturn is better viewed in the second half of January. Near mid-month, watch for Mercury and Saturn to meet up for their conjunction as the predawn darkness starts to give way to dawn. The brightest planet, Venus, is lost in the sun’s glare all month long, as it transitions from the morning to evening sky. Follow the links below to learn more about the planets in January 2018.

Venus transitions from morning to evening sky

Jupiter lights up predawn/dawn sky

Mars near Jupiter in predawn sky

Saturn climbs out of the sunrise glare

Mercury lights up morning sky

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You won’t see the moon with Venus in January 2018. This photo is from November 2017 – when the crescent moon made a triangle with Jupiter (top) and Venus before dawn. Photo taken over Valletta Lighthouse from Tigné Point on the island of Malta, by Gilbert Vancell Nature Photography.

Venus transitions from morning to evening sky Venus ranks as the third-brightest celestial body to light up our sky, after the sun and moon. Even so, this planet will be out of view as it moves from the morning to evening sky in January 2018.

You might have to wait until February or March 2018 to catch Venus in the west after sunset. In February 2018, Venus will set only a short while after the sun.

Did you see the spectacular conjunction of Venus and Jupiter in the morning sky on or around November 13, 2017? If not, check out these photos. Since the conjunction, Jupiter has been climbing away from the glare of sunrise day by day while Venus has been falling toward the sunrise daily. Throughout January 2018, Venus remains totally lost is the sun’s glare.

Conjunction of Venus and Jupiter over downtown Denver on November 13, after emerging from the clouds, via Christy Sanchez. Venus is the brighter object.

Venus reached a milestone as the morning “star” when it swung out to its greatest elongation from the sun on June 3, 2017. At this juncture, Venus was farthest from the sun on our sky’s dome, and a telescope showed Venus as half-illuminated in sunshine, like a first quarter moon. For the rest of the year, Venus will wax toward full phase.

Why a half Venus? Why a full Venus? It’s all about the angle at which we see Venus with respect to the sun. When we view Venus to one side of the sun – as we did when it was at its greatest elongation in June – then we see it as half illuminated. That is, we’re seeing half of Venus’ lighted half (a quarter Venus). Now, Venus is nearly behind the sun from Earth. We’re seeing more of its dayside: a nearly full Venus.

Click here to know Venus’s exact phase at present, remembering to select Venus as your object of interest.

The chart below helps to illustrate why we sometimes see Venus in the evening, and sometimes before dawn.

The Earth and Venus orbit the sun counterclockwise as seen from earthly north. When Venus is to the east (left) of the Earth-sun line, we see Venus as an evening “star” in the west after sunset. After Venus reaches its inferior conjunction, Venus then moves to the west (right) of the Earth-sun line, appearing as a morning “star” in the east before sunrise.

Let the waning crescent moon be your guide to the planets Jupiter and Mars for several days, centered on January 11. Read more

Jupiter lights up predawn/dawn sky. Because Venus is lost in the sun’s glare this month, the king planet Jupiter takes over as the brightest starlike object to adorn the nighttime sky. Jupiter beams during the predawn hours all month long.

This month, Jupiter shines in front of the constellation Libra the Scales and close to Libra’s alpha star, Zubenelgenubi. Use brilliant Jupiter to locate Zubenelgenubi, and then use binoculars to view this star as a double star!

Before dawn, look for modesty-bright Mars right above Jupiter in the first week of January. Then watch the gap between Jupiter and the red planet Mars rapidly come to a close. These two worlds will meet up in front of the constellation Libra for a stunningly close conjunction in the morning sky on January 7, 2018. After their conjunction, Jupiter will climb upward away from Mars.

Be sure to watch for the waning crescent moon near Jupiter (and Mars) for several mornings, centered on January 11.

From mid-northern latitudes, Jupiter rises about 4 hours before the sun (approximately 3 a.m. local time) in early January. By the month’s end, Jupiter comes up at around 2 a.m. local time.

From temperate latitudes in the Southern Hemisphere, Jupiter rises around 2 a.m. local time in early January; and by the month’s end, Jupiter rises around midnight.

Click here for an almanac telling you Jupiter’s rising time in your sky.

Fernando Roquel Torres in Caguas, Puerto Rico captured Jupiter, the Great Red Spot (GRS) and all 4 of its largest moons – the Galilean satellites – on the date of Jupiter’s 2017 opposition (April 7).

If you have binoculars or a telescope, it’s fairly easy to see Jupiter’s four major moons, which look like pinpricks of light all on or near the same plane. They are often called the Galilean moons to honor Galileo, who discovered these great Jovian moons in 1610. In their order from Jupiter, these moons are Io, Europa, Ganymede and Callisto.

These moons orbit Jupiter around the Jovian equator. In cycles of six years, we view Jupiter’s equator edge-on. So, in 2015, we were able to view a number of mutual events involving Jupiter’s moons, through high-powered telescopes. Starting in late 2016, Jupiter’s axis began tilting enough toward the sun and Earth so that the farthest of these four moons, Callisto, has not been passing in front of Jupiter or behind Jupiter, as seen from our vantage point. This will continue for a period of about three years, during which time Callisto is perpetually visible to those with telescopes, alternately swinging above and below Jupiter as seen from Earth.

Click here for a Jupiter’s moons almanac, courtesy of skyandtelescope.com.

Mars, Mercury, Earth’s moon and the dwarf planet Ceres. Mars is smaller than Earth, but bigger than our moon. Image via NASA/JPL-Caltech/UCLA.

It’ll be easy to see the conjunction of Mars and Jupiter in the predawn sky on January 7, 2018. It’ll be more of a challenge to catch Mercury as the predawn darkness gives way to dawn. Read more.

Mars near Jupiter in predawn sky. Look for Mars (and Jupiter) to rise in the east several hours before the first stirrings of morning twilight. Mars and Jupiter are the only naked-eye planets to grace the predawn sky all month long (although Mercury and Saturn play peekaboo at and around dawn). Mars starts out the month about 3^o above the king planet Jupiter. (For reference, one finger-width at an arm length spans about 2^o of sky.) The gap between Mars and Jupiter will quickly close as the two worlds meet up for a conjunction on January 7, 2018.

It’s best to look for Mars before dawn (approximately one and one-half hours before sunrise) because this ruddy gem is only modestly bright right now. Mars is nowhere as brilliant as Jupiter, which outshines Mars by about 20 times in early January. Jupiter is even visible in a twilight sky.

Be sure to let the waning crescent moon help guide your eye to Mars (and Jupiter) for several mornings, centered on January 11.

Exactly one year after Mars’s superior conjunction on July 27, 2017, Mars will swing to opposition on July 27, 2018. This will be Mars’s best opposition since its historically close opposition on August 28, 2003. In fact, Mars will become the fourth-brightest heavenly body to light up the sky in July 2018, after the sun, moon and the planet Venus. It’s not often that Mars outshines Jupiter, normally the fourth-brightest celestial body.

James Martin in Albuquerque, New Mexico caught this wonderful photo of Saturn on its June 15, 2017 opposition.

Given clear skies, it’ll be easy to see the moon with Jupiter and Mars on January 11. It’ll be tougher to catch Mercury, and especially Saturn, as the predawn darkness gives way to dawn. Binoculars may come in handy! Click here for a sky almanac giving you Mercury and Saturn’s rising times in your sky.

Saturn climbs out of the sunrise glare. Saturn transitioned out of the evening sky and into the morning sky on the December solstice, and might not be seen in the morning sky until the Mercury and Saturn conjunction on January 13, 2018.

Saturn, the farthest world that you can easily view with the eye alone, appears golden in color. It shines with a steady light. Let the waning crescent moon help guide your eye to Saturn (and Mercury) for several mornings, starting around January 12.

From mid-northern latitudes (US and Europe), Saturn rises about 45 minutes before sunrise in early January. By the month’s end, look for Saturn to rise better than two hours before the sun.

From temperate latitudes in the Southern Hemisphere (South Africa, southern Australia), Saturn rises about 45 minutes before sunrise in early January; and by the month’s end, the ringed planet comes up nearly 3 hours before the sun.

Binoculars don’t reveal Saturn’s gorgeous rings, by the way, although binoculars will enhance Saturn’s color. To see the rings, you need a small telescope. A telescope will also reveal one or more of Saturn’s many moons, most notably Titan.

Saturn’s rings are now inclined at about 26^o from edge-on, exhibiting their northern face. In 2017, the north side of the rings opened up most widely (27^o) since since the last grand opening in 1988. The next maximum exposure of the north side of Saturn’s rings will take place in 2046.

As with so much in space (and on Earth), the appearance of Saturn’s rings from Earth is cyclical. In the year 2025, the rings will appear edge-on as seen from Earth. After that, we’ll begin to see the south side of Saturn’s rings, to increase to a maximum inclination of 27^o by May 2032.

Click here for recommended almanacs; they can help you know when the planets rise, transit and set in your sky.

November 21, 2017 photo of the waxing crescent moon, Saturn and Mercury in the evening sky via Annie Lewis in Madrid, Spain.

Use the lit side of the moon to find Mercury and Saturn pairing up together in the morning sky on January 12, 13 and 14, 2018. Read more.

Mercury before sunrise in early January. Mercury will be in the morning sky all month long. But it will be sinking toward the sunrise day by day, so the first half of the month is more opportune for seeing the solar system’s innermost planet. Be sure to watch the conjunction of Mercury and Saturn on January 13, 2018.

After their conjunction, Mercury will sink toward the sunrise whereas Saturn will climb away from the glare of morning twilight. By February, Saturn will be easy to see in the predawn sky, whereas Mercury will have disappeared from view.

At mid-northern latitudes – such as in the United States and Europe – Mercury will rise about 100 minutes before the sun in early January. By the month’s end, that’ll taper to about 30 minutes before sunrise.

At temperate latitudes in the Southern Hemisphere – South Africa, southern Australia and New Zealand – Mercury rises about 90 minutes before the sun in early January; and by the month’s end, will rise about one hour before the sun.

Mercury is tricky, even when it becomes visible. If you look too early, Mercury will still be under the horizon; if you look too late, it will be obscured by morning twilight. Watch for Mercury low in the sky, and near the sunrise point on the horizon, being mindful of Mercury’s rising time.

Use the lit part of the waning crescent moon to find Mercury pairing up with Saturn on the mornings of January 12, 13 and 14. (See above sky chart.)

What do we mean by bright planet? By bright planet, we mean any solar system planet that is easily visible without an optical aid and that has been watched by our ancestors since time immemorial. In their outward order from the sun, the five bright planets are Mercury, Venus, Mars, Jupiter and Saturn. These planets actually do appear bright in our sky. They are typically as bright as – or brighter than – the brightest stars. Plus, these relatively nearby worlds tend to shine with a steadier light than the distant, twinkling stars. You can spot them, and come to know them as faithful friends, if you try.

This image is from February 8, 2016. It shows all 5 bright planets at once. Photo by our friend Eliot Herman in Tucson, Arizona.

Skywatcher, by Predrag Agatonovic.

Bottom line: Four of the five bright planets – Mercury, Mars, Jupiter and Saturn – reign as morning planets. Mars and Jupiter showcase a close conjunction on January 7. Mercury and Saturn stage their conjunction on January 13. Venus is lost in the sun’s glare all month long.

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Three bright planets and two bright stars adorn the morning sky in early January 2018. (Saturn appears later in the month.) An imaginary line drawn from the star Spica through the planets Jupiter and Mars helps you to locate Mercury near the horizon. Binoculars may be helpful. Click here for a recommended almanac that’ll give you Mercury’s rising time in your sky.

Four of the five bright planets – Mercury, Mars, Jupiter and Saturn – reside exclusively in the morning sky, before sunup, in January 2018. Mars and Jupiter are easy. They light up the predawn hours all month long and are in conjunction on January 7. Mercury is better seen in the first half of the month whereas Saturn is better viewed in the second half of January. Near mid-month, watch for Mercury and Saturn to meet up for their conjunction as the predawn darkness starts to give way to dawn. The brightest planet, Venus, is lost in the sun’s glare all month long, as it transitions from the morning to evening sky. Follow the links below to learn more about the planets in January 2018.

Venus transitions from morning to evening sky

Jupiter lights up predawn/dawn sky

Mars near Jupiter in predawn sky

Saturn climbs out of the sunrise glare

Mercury lights up morning sky

EarthSky’s 2018 lunar calendars are here! Get yours while they last.

Like what EarthSky offers? Sign up for our free daily newsletter today!

Astronomy events, star parties, festivals, workshops

Visit a new EarthSky feature – Best Places to Stargaze – and add your fav.

You won’t see the moon with Venus in January 2018. This photo is from November 2017 – when the crescent moon made a triangle with Jupiter (top) and Venus before dawn. Photo taken over Valletta Lighthouse from Tigné Point on the island of Malta, by Gilbert Vancell Nature Photography.

Venus transitions from morning to evening sky Venus ranks as the third-brightest celestial body to light up our sky, after the sun and moon. Even so, this planet will be out of view as it moves from the morning to evening sky in January 2018.

You might have to wait until February or March 2018 to catch Venus in the west after sunset. In February 2018, Venus will set only a short while after the sun.

Did you see the spectacular conjunction of Venus and Jupiter in the morning sky on or around November 13, 2017? If not, check out these photos. Since the conjunction, Jupiter has been climbing away from the glare of sunrise day by day while Venus has been falling toward the sunrise daily. Throughout January 2018, Venus remains totally lost is the sun’s glare.

Conjunction of Venus and Jupiter over downtown Denver on November 13, after emerging from the clouds, via Christy Sanchez. Venus is the brighter object.

Venus reached a milestone as the morning “star” when it swung out to its greatest elongation from the sun on June 3, 2017. At this juncture, Venus was farthest from the sun on our sky’s dome, and a telescope showed Venus as half-illuminated in sunshine, like a first quarter moon. For the rest of the year, Venus will wax toward full phase.

Why a half Venus? Why a full Venus? It’s all about the angle at which we see Venus with respect to the sun. When we view Venus to one side of the sun – as we did when it was at its greatest elongation in June – then we see it as half illuminated. That is, we’re seeing half of Venus’ lighted half (a quarter Venus). Now, Venus is nearly behind the sun from Earth. We’re seeing more of its dayside: a nearly full Venus.

Click here to know Venus’s exact phase at present, remembering to select Venus as your object of interest.

The chart below helps to illustrate why we sometimes see Venus in the evening, and sometimes before dawn.

The Earth and Venus orbit the sun counterclockwise as seen from earthly north. When Venus is to the east (left) of the Earth-sun line, we see Venus as an evening “star” in the west after sunset. After Venus reaches its inferior conjunction, Venus then moves to the west (right) of the Earth-sun line, appearing as a morning “star” in the east before sunrise.

Let the waning crescent moon be your guide to the planets Jupiter and Mars for several days, centered on January 11. Read more

Jupiter lights up predawn/dawn sky. Because Venus is lost in the sun’s glare this month, the king planet Jupiter takes over as the brightest starlike object to adorn the nighttime sky. Jupiter beams during the predawn hours all month long.

This month, Jupiter shines in front of the constellation Libra the Scales and close to Libra’s alpha star, Zubenelgenubi. Use brilliant Jupiter to locate Zubenelgenubi, and then use binoculars to view this star as a double star!

Before dawn, look for modesty-bright Mars right above Jupiter in the first week of January. Then watch the gap between Jupiter and the red planet Mars rapidly come to a close. These two worlds will meet up in front of the constellation Libra for a stunningly close conjunction in the morning sky on January 7, 2018. After their conjunction, Jupiter will climb upward away from Mars.

Be sure to watch for the waning crescent moon near Jupiter (and Mars) for several mornings, centered on January 11.

From mid-northern latitudes, Jupiter rises about 4 hours before the sun (approximately 3 a.m. local time) in early January. By the month’s end, Jupiter comes up at around 2 a.m. local time.

From temperate latitudes in the Southern Hemisphere, Jupiter rises around 2 a.m. local time in early January; and by the month’s end, Jupiter rises around midnight.

Click here for an almanac telling you Jupiter’s rising time in your sky.

Fernando Roquel Torres in Caguas, Puerto Rico captured Jupiter, the Great Red Spot (GRS) and all 4 of its largest moons – the Galilean satellites – on the date of Jupiter’s 2017 opposition (April 7).

If you have binoculars or a telescope, it’s fairly easy to see Jupiter’s four major moons, which look like pinpricks of light all on or near the same plane. They are often called the Galilean moons to honor Galileo, who discovered these great Jovian moons in 1610. In their order from Jupiter, these moons are Io, Europa, Ganymede and Callisto.

These moons orbit Jupiter around the Jovian equator. In cycles of six years, we view Jupiter’s equator edge-on. So, in 2015, we were able to view a number of mutual events involving Jupiter’s moons, through high-powered telescopes. Starting in late 2016, Jupiter’s axis began tilting enough toward the sun and Earth so that the farthest of these four moons, Callisto, has not been passing in front of Jupiter or behind Jupiter, as seen from our vantage point. This will continue for a period of about three years, during which time Callisto is perpetually visible to those with telescopes, alternately swinging above and below Jupiter as seen from Earth.

Click here for a Jupiter’s moons almanac, courtesy of skyandtelescope.com.

Mars, Mercury, Earth’s moon and the dwarf planet Ceres. Mars is smaller than Earth, but bigger than our moon. Image via NASA/JPL-Caltech/UCLA.

It’ll be easy to see the conjunction of Mars and Jupiter in the predawn sky on January 7, 2018. It’ll be more of a challenge to catch Mercury as the predawn darkness gives way to dawn. Read more.

Mars near Jupiter in predawn sky. Look for Mars (and Jupiter) to rise in the east several hours before the first stirrings of morning twilight. Mars and Jupiter are the only naked-eye planets to grace the predawn sky all month long (although Mercury and Saturn play peekaboo at and around dawn). Mars starts out the month about 3^o above the king planet Jupiter. (For reference, one finger-width at an arm length spans about 2^o of sky.) The gap between Mars and Jupiter will quickly close as the two worlds meet up for a conjunction on January 7, 2018.

It’s best to look for Mars before dawn (approximately one and one-half hours before sunrise) because this ruddy gem is only modestly bright right now. Mars is nowhere as brilliant as Jupiter, which outshines Mars by about 20 times in early January. Jupiter is even visible in a twilight sky.

Be sure to let the waning crescent moon help guide your eye to Mars (and Jupiter) for several mornings, centered on January 11.

Exactly one year after Mars’s superior conjunction on July 27, 2017, Mars will swing to opposition on July 27, 2018. This will be Mars’s best opposition since its historically close opposition on August 28, 2003. In fact, Mars will become the fourth-brightest heavenly body to light up the sky in July 2018, after the sun, moon and the planet Venus. It’s not often that Mars outshines Jupiter, normally the fourth-brightest celestial body.

James Martin in Albuquerque, New Mexico caught this wonderful photo of Saturn on its June 15, 2017 opposition.

Given clear skies, it’ll be easy to see the moon with Jupiter and Mars on January 11. It’ll be tougher to catch Mercury, and especially Saturn, as the predawn darkness gives way to dawn. Binoculars may come in handy! Click here for a sky almanac giving you Mercury and Saturn’s rising times in your sky.

Saturn climbs out of the sunrise glare. Saturn transitioned out of the evening sky and into the morning sky on the December solstice, and might not be seen in the morning sky until the Mercury and Saturn conjunction on January 13, 2018.

Saturn, the farthest world that you can easily view with the eye alone, appears golden in color. It shines with a steady light. Let the waning crescent moon help guide your eye to Saturn (and Mercury) for several mornings, starting around January 12.

From mid-northern latitudes (US and Europe), Saturn rises about 45 minutes before sunrise in early January. By the month’s end, look for Saturn to rise better than two hours before the sun.

From temperate latitudes in the Southern Hemisphere (South Africa, southern Australia), Saturn rises about 45 minutes before sunrise in early January; and by the month’s end, the ringed planet comes up nearly 3 hours before the sun.

Binoculars don’t reveal Saturn’s gorgeous rings, by the way, although binoculars will enhance Saturn’s color. To see the rings, you need a small telescope. A telescope will also reveal one or more of Saturn’s many moons, most notably Titan.

Saturn’s rings are now inclined at about 26^o from edge-on, exhibiting their northern face. In 2017, the north side of the rings opened up most widely (27^o) since since the last grand opening in 1988. The next maximum exposure of the north side of Saturn’s rings will take place in 2046.

As with so much in space (and on Earth), the appearance of Saturn’s rings from Earth is cyclical. In the year 2025, the rings will appear edge-on as seen from Earth. After that, we’ll begin to see the south side of Saturn’s rings, to increase to a maximum inclination of 27^o by May 2032.

Click here for recommended almanacs; they can help you know when the planets rise, transit and set in your sky.

November 21, 2017 photo of the waxing crescent moon, Saturn and Mercury in the evening sky via Annie Lewis in Madrid, Spain.

Use the lit side of the moon to find Mercury and Saturn pairing up together in the morning sky on January 12, 13 and 14, 2018. Read more.

Mercury before sunrise in early January. Mercury will be in the morning sky all month long. But it will be sinking toward the sunrise day by day, so the first half of the month is more opportune for seeing the solar system’s innermost planet. Be sure to watch the conjunction of Mercury and Saturn on January 13, 2018.

After their conjunction, Mercury will sink toward the sunrise whereas Saturn will climb away from the glare of morning twilight. By February, Saturn will be easy to see in the predawn sky, whereas Mercury will have disappeared from view.

At mid-northern latitudes – such as in the United States and Europe – Mercury will rise about 100 minutes before the sun in early January. By the month’s end, that’ll taper to about 30 minutes before sunrise.

At temperate latitudes in the Southern Hemisphere – South Africa, southern Australia and New Zealand – Mercury rises about 90 minutes before the sun in early January; and by the month’s end, will rise about one hour before the sun.

Mercury is tricky, even when it becomes visible. If you look too early, Mercury will still be under the horizon; if you look too late, it will be obscured by morning twilight. Watch for Mercury low in the sky, and near the sunrise point on the horizon, being mindful of Mercury’s rising time.

Use the lit part of the waning crescent moon to find Mercury pairing up with Saturn on the mornings of January 12, 13 and 14. (See above sky chart.)

What do we mean by bright planet? By bright planet, we mean any solar system planet that is easily visible without an optical aid and that has been watched by our ancestors since time immemorial. In their outward order from the sun, the five bright planets are Mercury, Venus, Mars, Jupiter and Saturn. These planets actually do appear bright in our sky. They are typically as bright as – or brighter than – the brightest stars. Plus, these relatively nearby worlds tend to shine with a steadier light than the distant, twinkling stars. You can spot them, and come to know them as faithful friends, if you try.

This image is from February 8, 2016. It shows all 5 bright planets at once. Photo by our friend Eliot Herman in Tucson, Arizona.

Skywatcher, by Predrag Agatonovic.

Bottom line: Four of the five bright planets – Mercury, Mars, Jupiter and Saturn – reign as morning planets. Mars and Jupiter showcase a close conjunction on January 7. Mercury and Saturn stage their conjunction on January 13. Venus is lost in the sun’s glare all month long.

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Tides, and the pull of the moon and sun

This beautiful image is from EarthSky Facebook friend John Lloyd Griffith

In most places, but not everywhere, there are two high tides and two low tides a day. The difference in height between high and low tides varies, as the moon waxes and wanes from new to full and back to new again. The moon and sun are primarily responsible for the rising and falling of ocean tides, but, for any particular spot on Earth’s surface, the height of the tides and their fluctuation in time also depends on the shape of your specific beach, the angle of the seabed leading up your beach, plus your larger coastline and the prevailing ocean currents and winds. Following the January 1-2, 2018 supermoon, you can expect higher-than-usual tides. Click the links below to learn more.

Some background. What are spring tides?

Why does a supermoon cause more extreme tides?

What part does the sun play, in early 2018?

What are neap tides?

Why are there two high tides and two low tides each day?

Around each new moon and full moon – when the sun, Earth, and moon are located more or less on a line in space – the range between high and low tides is greatest. These are the spring tides. Image via physicalgeography.net

Some background. What are spring tides? Around each new moon and full moon, the sun, Earth, and moon arrange themselves more or less along a line in space. Then the pull on the tides increases, because the gravity of the sun reinforces the moon’s gravity. In fact, the height of the average solar tide is about 50% the average lunar tide.

Thus, at new moon or full moon, the tide’s range is at its maximum. This is the spring tide: the highest (and lowest) tide. Spring tides are not named for the season. This is spring in the sense of jump, burst forth, rise.

So spring tides bring the most extreme high and low tides every month, and they always happen – every month – around full and new moon.

New Year’s Eve moon – December 31, 2017 – from Mimi Ditchie near Avila Beach, California. She wrote: “Prelude to the Supermoon/Wolf Moon: This nearly full moon (98.1%) rose behind the clouds …”

Why does a supermoon cause more extreme tides? When the new moon or full moon closely aligns with perigee – closest point to Earth in the moon’s orbit – then we have a supermoon and extra-large spring tides. Some call these perigean spring tides. But since, in recent years, these close new or full moons have come to be called supermoons, it’s also likely some are already calling them supermoon tides, and we’ve also heard the term king tides.

In 2018, the January 1-2 full moon will closely align with perigee to bring forth perigean spring tides.

Why are the tides at their strongest around this time? It’s simply because the moon is at its closest to Earth, and thus the Earth’s oceans are feeling the pull of the moon’s gravity most powerfully.

Should you expect these extra-high tides on the day of the supermoon itself? Probably not. The highest tides tend to follow the supermoon by a day or two.

Do the most extreme high tides – high tides bringing floods – always occur at supermoons? Not necessarily. It’s when a spring tide coincides with a time of heavy winds and rain – flooding due to a weather extreme – that the most extreme flooding occurs.

Read more: 2018’s largest supermoon on January 1-2

Gary Peltz in Seattle, Washington caught these beautiful sunset reflections and the nearly full moon on December 31, 2017.

What part does the sun play, in early 2018? Not only the moon, but also the sun plays a role in Earth’s tides. You might see that – when Earth is closest to the sun, as it is every early January – the pull on Earth’s tides by the sun is strongest. We reach Earth’s closest point to the sun for 2018 on January 3 at 5:35 UTC; translate to your time zone. Astronomers call this special point in our orbit perihelion, from the Greek roots peri meaning near and helios meaning sun.

The closer-than-usual sun and closer-than-usual full moon will almost surely increase the high of high tides in the first few days of January, 2018.

Around each first quarter moon and last quarter moon – when the sun and moon are at a right angle to Earth – the range between high and low tides is least. These are the neap tides. Image via physicalgeography.net

What are neap tides? There’s about a seven-day interval between spring tides and neap tides, when the tide’s range is at its minimum. Neap tides occur halfway between each new and full moon – at the first quarter and last quarter moon phase – when the sun and moon are at right angles as seen from Earth. Then the sun’s gravity is working against the gravity of the moon, as the moon pulls on the sea. Neap tides happen approximately twice a month, once around first quarter moon and once around last quarter moon.

Earth has two tidal bulges, one of the side of Earth nearest the moon (where the moon’s gravity pulls hardest), and the other on the side of Earth farthest from the moon (where the moon’s gravity pulls least).

Why are there two high tides and two low tides each day? If the moon is primarily responsible for the tides, why are there two high tides and two low tides each day in most places, for example, the U.S. eastern seaboard? It seems as if there should just be one. If you picture the part of Earth closest to the moon, it’s easy to see that the ocean is drawn toward the moon. That’s because gravity depends in part on how close two objects are.

But then why – on the opposite side of Earth – is there another tidal bulge, in the direction opposite the moon? It seems counterintuitive, until you realize that this second bulge happens at the part of Earth where the moon’s gravity is pulling the least.

Looking for a tide almanac? EarthSky recommends …

Earth spins once every 24 hours. So a given location on Earth will pass “through” both bulges of water each day. Of course, the bulges don’t stay fixed in time. They move at the slow rate of about 13.1 degrees per day – the same rate as the monthly motion of the moon relative to the stars. Other factors, including the shape of coastlines, etc., also influence the time of the tides, which is why people who live near coastlines like to have a good tide almanac.

Bottom line: The sun, the moon, the shape of a beach and larger coastline, the angle of a seabed leading up to land, and the prevailing ocean currents and winds all affect the height of the tides. Expect higher-than-usual tides for a few days following the January 1-2, 2018 full supermoon.

Enjoying EarthSky? Sign up for our free daily newsletter today!

from EarthSky http://ift.tt/1kEGlB8

This beautiful image is from EarthSky Facebook friend John Lloyd Griffith

In most places, but not everywhere, there are two high tides and two low tides a day. The difference in height between high and low tides varies, as the moon waxes and wanes from new to full and back to new again. The moon and sun are primarily responsible for the rising and falling of ocean tides, but, for any particular spot on Earth’s surface, the height of the tides and their fluctuation in time also depends on the shape of your specific beach, the angle of the seabed leading up your beach, plus your larger coastline and the prevailing ocean currents and winds. Following the January 1-2, 2018 supermoon, you can expect higher-than-usual tides. Click the links below to learn more.

Some background. What are spring tides?

Why does a supermoon cause more extreme tides?

What part does the sun play, in early 2018?

What are neap tides?

Why are there two high tides and two low tides each day?

Around each new moon and full moon – when the sun, Earth, and moon are located more or less on a line in space – the range between high and low tides is greatest. These are the spring tides. Image via physicalgeography.net

Some background. What are spring tides? Around each new moon and full moon, the sun, Earth, and moon arrange themselves more or less along a line in space. Then the pull on the tides increases, because the gravity of the sun reinforces the moon’s gravity. In fact, the height of the average solar tide is about 50% the average lunar tide.

Thus, at new moon or full moon, the tide’s range is at its maximum. This is the spring tide: the highest (and lowest) tide. Spring tides are not named for the season. This is spring in the sense of jump, burst forth, rise.

So spring tides bring the most extreme high and low tides every month, and they always happen – every month – around full and new moon.

New Year’s Eve moon – December 31, 2017 – from Mimi Ditchie near Avila Beach, California. She wrote: “Prelude to the Supermoon/Wolf Moon: This nearly full moon (98.1%) rose behind the clouds …”

Why does a supermoon cause more extreme tides? When the new moon or full moon closely aligns with perigee – closest point to Earth in the moon’s orbit – then we have a supermoon and extra-large spring tides. Some call these perigean spring tides. But since, in recent years, these close new or full moons have come to be called supermoons, it’s also likely some are already calling them supermoon tides, and we’ve also heard the term king tides.

In 2018, the January 1-2 full moon will closely align with perigee to bring forth perigean spring tides.

Why are the tides at their strongest around this time? It’s simply because the moon is at its closest to Earth, and thus the Earth’s oceans are feeling the pull of the moon’s gravity most powerfully.

Should you expect these extra-high tides on the day of the supermoon itself? Probably not. The highest tides tend to follow the supermoon by a day or two.

Do the most extreme high tides – high tides bringing floods – always occur at supermoons? Not necessarily. It’s when a spring tide coincides with a time of heavy winds and rain – flooding due to a weather extreme – that the most extreme flooding occurs.

Read more: 2018’s largest supermoon on January 1-2

Gary Peltz in Seattle, Washington caught these beautiful sunset reflections and the nearly full moon on December 31, 2017.

What part does the sun play, in early 2018? Not only the moon, but also the sun plays a role in Earth’s tides. You might see that – when Earth is closest to the sun, as it is every early January – the pull on Earth’s tides by the sun is strongest. We reach Earth’s closest point to the sun for 2018 on January 3 at 5:35 UTC; translate to your time zone. Astronomers call this special point in our orbit perihelion, from the Greek roots peri meaning near and helios meaning sun.

The closer-than-usual sun and closer-than-usual full moon will almost surely increase the high of high tides in the first few days of January, 2018.

Around each first quarter moon and last quarter moon – when the sun and moon are at a right angle to Earth – the range between high and low tides is least. These are the neap tides. Image via physicalgeography.net

What are neap tides? There’s about a seven-day interval between spring tides and neap tides, when the tide’s range is at its minimum. Neap tides occur halfway between each new and full moon – at the first quarter and last quarter moon phase – when the sun and moon are at right angles as seen from Earth. Then the sun’s gravity is working against the gravity of the moon, as the moon pulls on the sea. Neap tides happen approximately twice a month, once around first quarter moon and once around last quarter moon.

Earth has two tidal bulges, one of the side of Earth nearest the moon (where the moon’s gravity pulls hardest), and the other on the side of Earth farthest from the moon (where the moon’s gravity pulls least).

Why are there two high tides and two low tides each day? If the moon is primarily responsible for the tides, why are there two high tides and two low tides each day in most places, for example, the U.S. eastern seaboard? It seems as if there should just be one. If you picture the part of Earth closest to the moon, it’s easy to see that the ocean is drawn toward the moon. That’s because gravity depends in part on how close two objects are.

But then why – on the opposite side of Earth – is there another tidal bulge, in the direction opposite the moon? It seems counterintuitive, until you realize that this second bulge happens at the part of Earth where the moon’s gravity is pulling the least.

Looking for a tide almanac? EarthSky recommends …

Earth spins once every 24 hours. So a given location on Earth will pass “through” both bulges of water each day. Of course, the bulges don’t stay fixed in time. They move at the slow rate of about 13.1 degrees per day – the same rate as the monthly motion of the moon relative to the stars. Other factors, including the shape of coastlines, etc., also influence the time of the tides, which is why people who live near coastlines like to have a good tide almanac.

Bottom line: The sun, the moon, the shape of a beach and larger coastline, the angle of a seabed leading up to land, and the prevailing ocean currents and winds all affect the height of the tides. Expect higher-than-usual tides for a few days following the January 1-2, 2018 full supermoon.

Enjoying EarthSky? Sign up for our free daily newsletter today!

from EarthSky http://ift.tt/1kEGlB8

New Year’s resolutions 2018: Can you nudge your way to a new you?

If you’ve made some healthy resolutions for 2018, understanding the science behind why we make certain decisions can help you keep on track. We spoke to UCL’s Dr Philippa Lally, who studies how we form habits, to find out how a behaviour science – called nudge theory – can help make your 2018 resolutions stick.

What is nudge theory?

Nudge theory is about introducing subtle changes, or ‘nudges’, into our lives to encourage certain choices. It’s about making the preferred choice the easiest choice, rather than forcing or forbidding other options. And crucially, it’s about making choices that people are happy with – nudging isn’t about tricking people.

Nudges have been used for years to advertise products, and governments also use nudging in public health policy, to help encourage people to do a certain thing. For example, tweaking text message reminders has been shown to help reduce the number of missed NHS appointments. By adding a phone number for cancelling the appointment, plus the cost to the NHS if you don’t go, missed appointments fell by a quarter in a pilot study.

So these small changes work. And research is showing they can help turn choices into habits.

Lally describes a habit as “an association between a situation and an action”.

Each time you do that thing in the same situation “the association becomes stronger”, she says.

“And changing your environment is much easier than trying to control yourself.”

A recent study has also shown how this could work for healthy diets. It looked at data from other research on the effectiveness of nudges in changing adults’ diet. Nudges, such as providing calorie information or changing the range of portion sizes, led to an average 15.3% increase in healthier dietary or nutritional choices.

Make the healthy choice the easy choice

The easiest choice is often the most convenient one. So make healthy choices more convenient. Studies have shown that the order of food on offer at a buffet significantly affects meal choices. People pick the foods that come first or that are easiest to take. So while you may think you’ll go out of your way to have bacon and eggs rather than granola – research suggests otherwise.

The opposite is also true, making food harder to get can help reduce the amount you eat. One study found that by simply changing the serving utensil from a spoon to tongs reduced the amount of food taken by 8-16%.

So putting the biscuits or wine at the back of the cupboard could help you to cut down.

“Habits are all about cues,” says Lally. “The best way not to perform a habit is not to encounter your cue. If you can control the context to remove the cues, that is the easiest thing to do. By far the best thing would be to throw the biscuits out, to remove the cue, but even moving them might help.”

Plan for success

“If you want to create a new habit, you need to think carefully about how you’re going to do it,” says Lally. “Making a plan as to how you are going to achieve your more general goal is a good way to encourage that behaviour. Then after enough time, it should become a habit.”

Many studies support the idea of short term goals, particularly for losing weight. These can be used alone, or in combination with more long-term goals.

“If you make a plan, for example: ‘every day after my lunch I will have a piece of fruit’, that is called an implementation intention. That begins to form the association even by just saying it.”

It’s also a behavioural phenomenon that the closer we see ourselves to a goal, the more motivated we are to complete it. By charting success through small individual tasks to reach a bigger goal, we may be more likely to stick to a resolution. There’s lots of evidence to suggest that monitoring progress can help with long term success.

“Monitoring is a really good thing, because it keeps the habit fresh in people’s minds. You could tick it on a sheet on your fridge every day, or set a reminder on your phone,” suggests Lally.

Strength in numbers

Creating a group resolution helps to tackle two common behavioural challenges. First, people often prefer to avoid losing rather than to pursue winning. If you fear that you’re missing out on something, you will be more motivated to achieve it. “People often make decisions based on what other people are doing,” says Lally. So FoMO could be a powerful ally.

Second, people generally place more emphasis on immediate rewards or punishment. This might explain why many people don’t exercise or eat healthily enough, because the immediate pleasure of the unhealthy option can outweigh the enjoyment of a healthy lifestyle in the future. By creating an immediate benefit, such as making exercise a way to spend time with friends, it becomes a positive thing to do, not just for any future gains. And several studies have shown that social support and participating as groups increases how active people are.

“Having social support in any change is always good,” says Lally. “If you go to a pub, and everybody else is drinking around you, that is hard, whereas if you are all not drinking, then that is a lot easier.”

Remember it’s not all-or-nothing

“People feel like you’ve got to stop eating everything that tastes nice and start running marathons,” says Lally. “But you can make a big difference to your health by consistently sticking to small changes.”

Habits don’t happen overnight. A habit is something that is done automatically because it has been done frequently in the past. So while nudges might help encourage healthy behaviour, they won’t become habits immediately.

It’s the age-old refrain: practice make perfect. The more often you do something, the easier it is to do automatically. And once something becomes a habit, you don’t have to think about doing it anymore.

So while a resolution might not be habit by the end of January, stick with it. And whatever your New Year’s resolution is, there are more tips and information on our website to help you along the way to making that change.

“These changes can feel like small decisions, but small habits can actually make a big difference to your life,” says Lally.

And with 4 in 10 cancers being preventable, a nudge might be all you need.

Sophia Lowes is a health information officer at Cancer Research UK

from Cancer Research UK – Science blog http://ift.tt/2CnljXJ

If you’ve made some healthy resolutions for 2018, understanding the science behind why we make certain decisions can help you keep on track. We spoke to UCL’s Dr Philippa Lally, who studies how we form habits, to find out how a behaviour science – called nudge theory – can help make your 2018 resolutions stick.

What is nudge theory?

Nudge theory is about introducing subtle changes, or ‘nudges’, into our lives to encourage certain choices. It’s about making the preferred choice the easiest choice, rather than forcing or forbidding other options. And crucially, it’s about making choices that people are happy with – nudging isn’t about tricking people.

Nudges have been used for years to advertise products, and governments also use nudging in public health policy, to help encourage people to do a certain thing. For example, tweaking text message reminders has been shown to help reduce the number of missed NHS appointments. By adding a phone number for cancelling the appointment, plus the cost to the NHS if you don’t go, missed appointments fell by a quarter in a pilot study.

So these small changes work. And research is showing they can help turn choices into habits.

Lally describes a habit as “an association between a situation and an action”.

Each time you do that thing in the same situation “the association becomes stronger”, she says.

“And changing your environment is much easier than trying to control yourself.”

A recent study has also shown how this could work for healthy diets. It looked at data from other research on the effectiveness of nudges in changing adults’ diet. Nudges, such as providing calorie information or changing the range of portion sizes, led to an average 15.3% increase in healthier dietary or nutritional choices.

Make the healthy choice the easy choice

The easiest choice is often the most convenient one. So make healthy choices more convenient. Studies have shown that the order of food on offer at a buffet significantly affects meal choices. People pick the foods that come first or that are easiest to take. So while you may think you’ll go out of your way to have bacon and eggs rather than granola – research suggests otherwise.

The opposite is also true, making food harder to get can help reduce the amount you eat. One study found that by simply changing the serving utensil from a spoon to tongs reduced the amount of food taken by 8-16%.

So putting the biscuits or wine at the back of the cupboard could help you to cut down.

“Habits are all about cues,” says Lally. “The best way not to perform a habit is not to encounter your cue. If you can control the context to remove the cues, that is the easiest thing to do. By far the best thing would be to throw the biscuits out, to remove the cue, but even moving them might help.”

Plan for success

“If you want to create a new habit, you need to think carefully about how you’re going to do it,” says Lally. “Making a plan as to how you are going to achieve your more general goal is a good way to encourage that behaviour. Then after enough time, it should become a habit.”

Many studies support the idea of short term goals, particularly for losing weight. These can be used alone, or in combination with more long-term goals.

“If you make a plan, for example: ‘every day after my lunch I will have a piece of fruit’, that is called an implementation intention. That begins to form the association even by just saying it.”

It’s also a behavioural phenomenon that the closer we see ourselves to a goal, the more motivated we are to complete it. By charting success through small individual tasks to reach a bigger goal, we may be more likely to stick to a resolution. There’s lots of evidence to suggest that monitoring progress can help with long term success.

“Monitoring is a really good thing, because it keeps the habit fresh in people’s minds. You could tick it on a sheet on your fridge every day, or set a reminder on your phone,” suggests Lally.

Strength in numbers

Creating a group resolution helps to tackle two common behavioural challenges. First, people often prefer to avoid losing rather than to pursue winning. If you fear that you’re missing out on something, you will be more motivated to achieve it. “People often make decisions based on what other people are doing,” says Lally. So FoMO could be a powerful ally.

Second, people generally place more emphasis on immediate rewards or punishment. This might explain why many people don’t exercise or eat healthily enough, because the immediate pleasure of the unhealthy option can outweigh the enjoyment of a healthy lifestyle in the future. By creating an immediate benefit, such as making exercise a way to spend time with friends, it becomes a positive thing to do, not just for any future gains. And several studies have shown that social support and participating as groups increases how active people are.

“Having social support in any change is always good,” says Lally. “If you go to a pub, and everybody else is drinking around you, that is hard, whereas if you are all not drinking, then that is a lot easier.”

Remember it’s not all-or-nothing

“People feel like you’ve got to stop eating everything that tastes nice and start running marathons,” says Lally. “But you can make a big difference to your health by consistently sticking to small changes.”

Habits don’t happen overnight. A habit is something that is done automatically because it has been done frequently in the past. So while nudges might help encourage healthy behaviour, they won’t become habits immediately.

It’s the age-old refrain: practice make perfect. The more often you do something, the easier it is to do automatically. And once something becomes a habit, you don’t have to think about doing it anymore.

So while a resolution might not be habit by the end of January, stick with it. And whatever your New Year’s resolution is, there are more tips and information on our website to help you along the way to making that change.

“These changes can feel like small decisions, but small habits can actually make a big difference to your life,” says Lally.

And with 4 in 10 cancers being preventable, a nudge might be all you need.

Sophia Lowes is a health information officer at Cancer Research UK

from Cancer Research UK – Science blog http://ift.tt/2CnljXJ

Next New Horizons flyby will happen a year from today

View larger. | Artist’s concept of New Horizons’ trajectory, past Pluto, toward 2014 MU69.

One year from today – on January 1, 2019 – the famous Pluto spacecraft called New Horizons will encounter its next target, some billion miles (1.6 billion km) past Pluto, a Kuiper Belt object designated 2014 MU69. New Horizons’ science team has been abuzz since last summer, when the team learned via an occultation of a star by MU69 that this remote and tiny object might be either peanut-shaped or even two objects orbiting one another. In other words, perhaps MU69 is like a binary asteroid (aka an asteroid with a moon).

In December, New Horizons science team member Marc Buie of the Southwest Research Institute in Boulder, Colorado offered an update on scientists’ thoughts about MU69 at the fall meeting of the American Geophysical Union in New Orleans. He said in a statement:

We really won’t know what MU69 looks like until we fly past it, or even gain a full understanding of it until after the encounter. But even from afar, the more we examine it, the more interesting and amazing this little world becomes.

In particular, data collected during a July 10, 2017 occultation of a star by MU69 has led scientists to suspect MU69 might be binary. Scientists were aboard NASA’s airborne Stratospheric Observatory for Infrared Astronomy (SOFIA) – flying over the Pacific Ocean – when they saw what appeared to be a very short drop-out in the star’s light prior to the expected occultation. Buie said further analysis of that data, including syncing it with MU69 orbit calculations provided by the European Space Agency’s Gaia mission, opens the possibility that the “blip” SOFIA detected could be another object orbiting around MU69. Buie commented:

A binary with a smaller moon might also help explain the shifts we see in the position of MU69 during these various occultations. It’s all very suggestive, but another step in our work to get a clear picture of MU69 before New Horizons flies by … a year from now.

Read more about what the occultation data showed, via New Horizons

In 2017, the small Kuiper Belt object 2014 MU69 occulted (briefly hid) 3 faint stars as seen from Earth. Here are the pre-predicted tracks, each only about 30 miles (50 km) wide, from which those disappearances were visible. New Horizons scientists made every effort to observe these occultations, since such events can reveal much about the occulting object. Image via skyandtelescope.com.

View larger. | In this image, the colored lines mark the path of the star occulted by 2014 MU69, as seen from different telescopes on different days. The blank spaces on those lines indicate the few seconds when MU69 blocked the light from the star. Graphic via NASA/ Johns Hopkins University Applied Physics Laboratory/ Southwest Research Institute/ James Tuttle Keane/ New Horizons.

By the way, the New Horizons team was looking this past fall for your ideas on an informal name for 2014 MU69. The voting is closed now, but the announcement of the winner is expected soon; it wouldn’t surprise me if it came today. Meanwhile, you can see the 37 names being considered by the team, and see the results of the voting.

At present, Mjölnir – the name of Thor’s hammer in Norse mythology – is leading the pack by a substantial margin. Pronunciation here.

Read more about the voting on a nickname for 2014 MU69

Thus the Kuiper Belt object MU69, discovered as recently as 2014, is poised to become much better known. This object is more than 4 billion miles (6.5 billion km) from Earth. It appears to be no more than 20 miles (30 km) long, or, if a binary, each about 9-12 miles (15-20 km) in diameter.

We live in a wondrous age!

Artist’s concept of NASA’s New Horizons spacecraft streaking past 2014 MU69, which might be 2 objects orbiting each other. Image via Carlos Hernandez/ NASA.

Bottom line: The New Horizons spacecraft will sweep closest to Kuiper Belt object 2014 MU69 one year from today, on January 1, 2019.

from EarthSky http://ift.tt/2lzYHsp

View larger. | Artist’s concept of New Horizons’ trajectory, past Pluto, toward 2014 MU69.

One year from today – on January 1, 2019 – the famous Pluto spacecraft called New Horizons will encounter its next target, some billion miles (1.6 billion km) past Pluto, a Kuiper Belt object designated 2014 MU69. New Horizons’ science team has been abuzz since last summer, when the team learned via an occultation of a star by MU69 that this remote and tiny object might be either peanut-shaped or even two objects orbiting one another. In other words, perhaps MU69 is like a binary asteroid (aka an asteroid with a moon).

In December, New Horizons science team member Marc Buie of the Southwest Research Institute in Boulder, Colorado offered an update on scientists’ thoughts about MU69 at the fall meeting of the American Geophysical Union in New Orleans. He said in a statement:

We really won’t know what MU69 looks like until we fly past it, or even gain a full understanding of it until after the encounter. But even from afar, the more we examine it, the more interesting and amazing this little world becomes.

In particular, data collected during a July 10, 2017 occultation of a star by MU69 has led scientists to suspect MU69 might be binary. Scientists were aboard NASA’s airborne Stratospheric Observatory for Infrared Astronomy (SOFIA) – flying over the Pacific Ocean – when they saw what appeared to be a very short drop-out in the star’s light prior to the expected occultation. Buie said further analysis of that data, including syncing it with MU69 orbit calculations provided by the European Space Agency’s Gaia mission, opens the possibility that the “blip” SOFIA detected could be another object orbiting around MU69. Buie commented:

A binary with a smaller moon might also help explain the shifts we see in the position of MU69 during these various occultations. It’s all very suggestive, but another step in our work to get a clear picture of MU69 before New Horizons flies by … a year from now.

Read more about what the occultation data showed, via New Horizons

In 2017, the small Kuiper Belt object 2014 MU69 occulted (briefly hid) 3 faint stars as seen from Earth. Here are the pre-predicted tracks, each only about 30 miles (50 km) wide, from which those disappearances were visible. New Horizons scientists made every effort to observe these occultations, since such events can reveal much about the occulting object. Image via skyandtelescope.com.

View larger. | In this image, the colored lines mark the path of the star occulted by 2014 MU69, as seen from different telescopes on different days. The blank spaces on those lines indicate the few seconds when MU69 blocked the light from the star. Graphic via NASA/ Johns Hopkins University Applied Physics Laboratory/ Southwest Research Institute/ James Tuttle Keane/ New Horizons.

By the way, the New Horizons team was looking this past fall for your ideas on an informal name for 2014 MU69. The voting is closed now, but the announcement of the winner is expected soon; it wouldn’t surprise me if it came today. Meanwhile, you can see the 37 names being considered by the team, and see the results of the voting.

At present, Mjölnir – the name of Thor’s hammer in Norse mythology – is leading the pack by a substantial margin. Pronunciation here.

Read more about the voting on a nickname for 2014 MU69

Thus the Kuiper Belt object MU69, discovered as recently as 2014, is poised to become much better known. This object is more than 4 billion miles (6.5 billion km) from Earth. It appears to be no more than 20 miles (30 km) long, or, if a binary, each about 9-12 miles (15-20 km) in diameter.

We live in a wondrous age!

Artist’s concept of NASA’s New Horizons spacecraft streaking past 2014 MU69, which might be 2 objects orbiting each other. Image via Carlos Hernandez/ NASA.

Bottom line: The New Horizons spacecraft will sweep closest to Kuiper Belt object 2014 MU69 one year from today, on January 1, 2019.

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Year’s largest supermoon on January 1-2

Top image: December 3, 2017 supermoon via Henrique Feliciano Silva in Lisbon, Portugal.

See more images of December’s supermoon.

The first of two January 2018 full moons falls on the evening of January 1, 2018, for most of the Western Hemisphere (January 2 for the Eastern Hemisphere). This full moon comes only 4.5 hours after the moon reaches lunar perigee – the moon’s closest point to Earth in its monthly orbit. Thus this full moon presents the closest – and thereby the largest and brightest – supermoon of 2018.

Of the 13 full moons and 14 lunar perigees occurring in 2018, this is the closest alignment of full moon and lunar perigee for the year.

This close coincidence of full moon and perigee in early January 2018 not only gives us the closest full moon of 2018 but also the closest lunar perigee of 2018. See below to note the nearness in time of this perigee and full moon.

Lunar perigee distance (2018 Jan 1 at 21:54 UTC): 356,565 km
Full moon distance (2018 Jan 2 at 2:24 UTC): 356,846 km

Join the Virtual Telescope Project in Rome for an online viewing of the January 1, 2018 supermoon.

Here’s a comparison between the December 3 full moon at perigree (closest to Earth for the month) and the year’s farthest full moon in June at apogee (farthest from Earth for the month) by Muzamir Mazlan at Telok Kemang Observatory, Port Dickson, Malaysia. See more photos of December’s supermoon.

To the eye alone, a supermoon probably doesn’t look any larger than an ordinary full moon (although it might look brighter). But Earth’s oceans feel the gravity of the extra-close supermoon, which causes particularly high and low tides. James Younger wrote on December 3, 2017: “I held a low-tide supermoon photography event at Island View Beach, Vancouver Island, B.C..” See more photos of December’s supermoon.

Although the moon turns precisely full at the same instant worldwide (January 2 at 2:24 Universal Time), the time – and possibly the date – of the full moon varies according to one’s time zone. At North American and US time zones, the full moon actually comes to pass on the evening of January 1 at these times:

22:24 (10:24 p.m.) Atlantic Standard Time (AST)
21:24 (9:24 p.m.) Eastern Standard Time (EST)
20:24 (8:24 p.m.) Central Standard Time (CST)
19:24 (7:24 p.m.) Mountain Standard Time (MST)
18:24 (6:24 p.m.) Pacific Standard Time (PST)
17:24 (5:24 p.m.) Alaska Standard Time (AKST)
16:24 (4:24 p.m.) Hawaiian Standard Time (HST)

Astronomers say the moon is full at the instant that the moon is directly opposite the sun in ecliptic or celestial longitude. Another way of looking at it, the moon-sun elongation at full moon equals 180^o. Click here to find out the present moon-sun elongation, remembering that a positive number means a waxing moon and a negative number a waning moon.

However, since the moon stays more or less opposite the sun throughout the night tonight, we can say the moon is full all night long. Around the world tonight, we can expect the moon to rise around sunset, climb highest up for the night around midnight and to set around sunrise. On the night of the full moon, the moon typically shines from dusk until dawn.

Image via US Naval Observatory. The day and night sides of Earth at the instant of full moon (2018 January 2 at 2:24 Universal Time). The shadow line at left depicts sunset January 1, and the shadow line at right represents sunrise January 2.

Tonight’s full moon is the second in a series of three successive full moon supermoons occurring on December 3, 2017, plus January 2 and 31, 2018. As is typically the case, the second of these three full moon supermoons most closely coincides with lunar perigee, showcasing the closest and largest supermoon in this grand procession of supermoons.

Full moon distance (2017 Dec 3 at 15:47 UTC): 357,987 km
Lunar apogee distance (2017 Dec 4 at 8:42 UTC): 357,492 km

Full moon distance (2018 Jan 2 at 2:24 UTC): 356,846 km
Lunar perigee distance (2018 Jan 1 at 21:54 UTC): 356,565 km

Full moon distance (2018 Jan 31 at 13:27 UTC): 360,199 km
Lunar perigee distance (2018 Jan 30 at 9:54 UTC): 358,995 km

Tonight’s full moon is also the first of two January 2018 full moons. Some people will call the next full moon on January 31 a Blue Moon because it’s the second of two full moons to occur in one calendar month. Moreover, this second supermoon of January 2018 will stage a total eclipse of the moon.

Super Blue Moon eclipse coming up on January 31

Seven lunar months (full moons) after the year’s closest supermoon will usher in the smallest full moon of the year (micro-moon) on July 27, 2018. At that juncture, the full moon and lunar apogee – the moon’s farthest point from Earth in its orbit – will both fall on the same date. That full moon on July 27, 2018, will be nearly 30,000 miles (50,000 km) farther from Earth than tonight’s closest and largest supermoon.

Jacob Zimmer caught the December 3, 2017 full supermoon over downtown Tampa, Florida. See more photos of December’s supermoon.

Bottom line: Enjoy the “most super” supermoon of the year on the night of January 1-2, 2018, as it lights up the nighttime from dusk to dawn.

Resources:

Phases of the moon: 2001 to 2100

Moon at perigee and apogee: 2001 to 2100

Lunar perigee and apogee calculator

from EarthSky http://ift.tt/2ibNA7D

Top image: December 3, 2017 supermoon via Henrique Feliciano Silva in Lisbon, Portugal.

See more images of December’s supermoon.

The first of two January 2018 full moons falls on the evening of January 1, 2018, for most of the Western Hemisphere (January 2 for the Eastern Hemisphere). This full moon comes only 4.5 hours after the moon reaches lunar perigee – the moon’s closest point to Earth in its monthly orbit. Thus this full moon presents the closest – and thereby the largest and brightest – supermoon of 2018.

Of the 13 full moons and 14 lunar perigees occurring in 2018, this is the closest alignment of full moon and lunar perigee for the year.

This close coincidence of full moon and perigee in early January 2018 not only gives us the closest full moon of 2018 but also the closest lunar perigee of 2018. See below to note the nearness in time of this perigee and full moon.

Lunar perigee distance (2018 Jan 1 at 21:54 UTC): 356,565 km
Full moon distance (2018 Jan 2 at 2:24 UTC): 356,846 km

Join the Virtual Telescope Project in Rome for an online viewing of the January 1, 2018 supermoon.

Here’s a comparison between the December 3 full moon at perigree (closest to Earth for the month) and the year’s farthest full moon in June at apogee (farthest from Earth for the month) by Muzamir Mazlan at Telok Kemang Observatory, Port Dickson, Malaysia. See more photos of December’s supermoon.

To the eye alone, a supermoon probably doesn’t look any larger than an ordinary full moon (although it might look brighter). But Earth’s oceans feel the gravity of the extra-close supermoon, which causes particularly high and low tides. James Younger wrote on December 3, 2017: “I held a low-tide supermoon photography event at Island View Beach, Vancouver Island, B.C..” See more photos of December’s supermoon.

Although the moon turns precisely full at the same instant worldwide (January 2 at 2:24 Universal Time), the time – and possibly the date – of the full moon varies according to one’s time zone. At North American and US time zones, the full moon actually comes to pass on the evening of January 1 at these times:

22:24 (10:24 p.m.) Atlantic Standard Time (AST)
21:24 (9:24 p.m.) Eastern Standard Time (EST)
20:24 (8:24 p.m.) Central Standard Time (CST)
19:24 (7:24 p.m.) Mountain Standard Time (MST)
18:24 (6:24 p.m.) Pacific Standard Time (PST)
17:24 (5:24 p.m.) Alaska Standard Time (AKST)
16:24 (4:24 p.m.) Hawaiian Standard Time (HST)

Astronomers say the moon is full at the instant that the moon is directly opposite the sun in ecliptic or celestial longitude. Another way of looking at it, the moon-sun elongation at full moon equals 180^o. Click here to find out the present moon-sun elongation, remembering that a positive number means a waxing moon and a negative number a waning moon.

However, since the moon stays more or less opposite the sun throughout the night tonight, we can say the moon is full all night long. Around the world tonight, we can expect the moon to rise around sunset, climb highest up for the night around midnight and to set around sunrise. On the night of the full moon, the moon typically shines from dusk until dawn.

Image via US Naval Observatory. The day and night sides of Earth at the instant of full moon (2018 January 2 at 2:24 Universal Time). The shadow line at left depicts sunset January 1, and the shadow line at right represents sunrise January 2.

Tonight’s full moon is the second in a series of three successive full moon supermoons occurring on December 3, 2017, plus January 2 and 31, 2018. As is typically the case, the second of these three full moon supermoons most closely coincides with lunar perigee, showcasing the closest and largest supermoon in this grand procession of supermoons.

Full moon distance (2017 Dec 3 at 15:47 UTC): 357,987 km
Lunar apogee distance (2017 Dec 4 at 8:42 UTC): 357,492 km

Full moon distance (2018 Jan 2 at 2:24 UTC): 356,846 km
Lunar perigee distance (2018 Jan 1 at 21:54 UTC): 356,565 km

Full moon distance (2018 Jan 31 at 13:27 UTC): 360,199 km
Lunar perigee distance (2018 Jan 30 at 9:54 UTC): 358,995 km

Tonight’s full moon is also the first of two January 2018 full moons. Some people will call the next full moon on January 31 a Blue Moon because it’s the second of two full moons to occur in one calendar month. Moreover, this second supermoon of January 2018 will stage a total eclipse of the moon.

Super Blue Moon eclipse coming up on January 31

Seven lunar months (full moons) after the year’s closest supermoon will usher in the smallest full moon of the year (micro-moon) on July 27, 2018. At that juncture, the full moon and lunar apogee – the moon’s farthest point from Earth in its orbit – will both fall on the same date. That full moon on July 27, 2018, will be nearly 30,000 miles (50,000 km) farther from Earth than tonight’s closest and largest supermoon.

Jacob Zimmer caught the December 3, 2017 full supermoon over downtown Tampa, Florida. See more photos of December’s supermoon.

Bottom line: Enjoy the “most super” supermoon of the year on the night of January 1-2, 2018, as it lights up the nighttime from dusk to dawn.

Resources:

Phases of the moon: 2001 to 2100

Moon at perigee and apogee: 2001 to 2100

Lunar perigee and apogee calculator

from EarthSky http://ift.tt/2ibNA7D