Wow! Juno’s 8th science flyby of Jupiter

Illustration of Juno near Jupiter, which combines real images of the planet from the spacecraft with Juno artistically “added in.” Image via NASA/JPL-Caltech/ AmericaSpace.

NASA’s Juno spacecraft has successfully completed its 8th science flyby of Jupiter, passing over the gas giant’s swirling cloud tops once again as it continues to unravel the mysteries of the largest planet in the solar system. The mission itself also now has a new project manager, who will oversee the continuing flow of information being sent back, which has already greatly expanded our knowledge of Jupiter, upending some theories and presenting new questions.

The new Juno project manager is Ed Hirst, of NASA’s Jet Propulsion Laboratory in Pasadena, California. He said on November 2, 2017:

All the science collected during the flyby was carried in Juno’s memory until yesterday, when Jupiter came out of solar conjunction [when the planet is behind the sun from Earth].

All science instruments and the spacecraft’s JunoCam were operating, and the new data are now being transmitted to Earth and being delivered into the hands of our science team.

The flyby occurred on October 24, (Perijove 9) but the confirmation of its success was delayed until October 31 by the solar conjunction, which interrupts communications between the spacecraft and Earth.

New enhanced view of Jupiter’s turbulent atmosphere, from the most recent flyby on October 24, 2017. Image via NASA/JPL-Caltech/ SwRI/ MSSS/ Björn Jónsson/ AmericaSpace.

New enhanced view of Jupiter’s turbulent atmosphere, from the most recent flyby on October 24, 2017. Image via NASA/JPL-Caltech/ SwRI/ MSSS/ Björn Jónsson/ AmericaSpace.

New enhanced view of Jupiter’s turbulent atmosphere, from the most recent flyby on October 24, 2017. Image via NASA/JPL-Caltech/ SwRI/ MSSS/ Björn Jónsson/ AmericaSpace.

Juno has been busy orbiting Jupiter since July 4, 2016, using its instruments to study the planet’s atmosphere, clouds and auroras. At its closest, the spacecraft passes within 2,100 miles (3,400 km) of Jupiter’s cloud tops, providing unprecedented views of the turbulent atmosphere, which often looks like it was painted by a cosmic watercolor artist. Hirst commented:

There is no more exciting place to be than in orbit around Jupiter and no team I’d rather be with than the Juno team. Our spacecraft is in great shape, and the team is looking forward to many more flybys of the solar system’s largest planet.

Juno previously found that Jupiter’s auroras seem to defy earthly laws of physics and are much more powerful than any on Earth. The auroras have also been studied more recently by NASA’s Chandra X-ray Observatory. The data from Juno has also shown that Jupiter is more complex internally than previously thought, with current theories being turned on their heads.

New Chandra image comparison of auroras seen at Jupiter’s north and south poles. Image via X-ray – NASA/CXC/UCL/W.Dunn et al; Optical, South Pole – NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstädt/Seán Doran; North Pole – NASA/JPL-Caltech/ SwRI/ MSSS/ AmericaSpace.

Jupiter as seen by Juno on October 24, 2017. Image via NASA/ JPL-Caltech/ MSSS/ SwRI/ Kevin M. Gill/ AmericaSpace.

Jupiter as seen by Juno on October 24, 2017. Image via NASA/ JPL-Caltech/ MSSS/ SwRI/ Kevin M. Gill/ AmericaSpace.

Earlier image showing closest-ever view of Jupiter’s Great Red Spot from Juno. Image via NASA/ JPL-Caltech/ MSSS/ SwRI/ Kevin M. Gill/ AmericaSpace.

Juno’s principal investigator Scott Bolton earlier told WIRED:

Almost nothing is as we anticipated. But it’s exciting that Jupiter is so different than we assumed.

Juno was first launched on October 5, 2011, and is the first spacecraft to visit Jupiter since Galileo, which ended its mission on September 21, 2003 by intentionally plummeting into Jupiter’s atmosphere, much like the Cassini probe did at Saturn last September.

Ed Hirst – Juno’s new project manager – has worked on the mission since the beginning, and also worked on the Galileo, Stardust and Genesis missions. He replaces Rick Nybakken, who was recently appointed deputy director for JPL’s Office of Safety and Mission Success.

Juno’s next close flyby of Jupiter will be on December 16, 2017.

Bottom line: New images and info from the Juno mission’s 8th science flyby of Jupiter.

from EarthSky http://ift.tt/2zxq5QA

Illustration of Juno near Jupiter, which combines real images of the planet from the spacecraft with Juno artistically “added in.” Image via NASA/JPL-Caltech/ AmericaSpace.

NASA’s Juno spacecraft has successfully completed its 8th science flyby of Jupiter, passing over the gas giant’s swirling cloud tops once again as it continues to unravel the mysteries of the largest planet in the solar system. The mission itself also now has a new project manager, who will oversee the continuing flow of information being sent back, which has already greatly expanded our knowledge of Jupiter, upending some theories and presenting new questions.

The new Juno project manager is Ed Hirst, of NASA’s Jet Propulsion Laboratory in Pasadena, California. He said on November 2, 2017:

All the science collected during the flyby was carried in Juno’s memory until yesterday, when Jupiter came out of solar conjunction [when the planet is behind the sun from Earth].

All science instruments and the spacecraft’s JunoCam were operating, and the new data are now being transmitted to Earth and being delivered into the hands of our science team.

The flyby occurred on October 24, (Perijove 9) but the confirmation of its success was delayed until October 31 by the solar conjunction, which interrupts communications between the spacecraft and Earth.

New enhanced view of Jupiter’s turbulent atmosphere, from the most recent flyby on October 24, 2017. Image via NASA/JPL-Caltech/ SwRI/ MSSS/ Björn Jónsson/ AmericaSpace.

New enhanced view of Jupiter’s turbulent atmosphere, from the most recent flyby on October 24, 2017. Image via NASA/JPL-Caltech/ SwRI/ MSSS/ Björn Jónsson/ AmericaSpace.

New enhanced view of Jupiter’s turbulent atmosphere, from the most recent flyby on October 24, 2017. Image via NASA/JPL-Caltech/ SwRI/ MSSS/ Björn Jónsson/ AmericaSpace.

Juno has been busy orbiting Jupiter since July 4, 2016, using its instruments to study the planet’s atmosphere, clouds and auroras. At its closest, the spacecraft passes within 2,100 miles (3,400 km) of Jupiter’s cloud tops, providing unprecedented views of the turbulent atmosphere, which often looks like it was painted by a cosmic watercolor artist. Hirst commented:

There is no more exciting place to be than in orbit around Jupiter and no team I’d rather be with than the Juno team. Our spacecraft is in great shape, and the team is looking forward to many more flybys of the solar system’s largest planet.

Juno previously found that Jupiter’s auroras seem to defy earthly laws of physics and are much more powerful than any on Earth. The auroras have also been studied more recently by NASA’s Chandra X-ray Observatory. The data from Juno has also shown that Jupiter is more complex internally than previously thought, with current theories being turned on their heads.

New Chandra image comparison of auroras seen at Jupiter’s north and south poles. Image via X-ray – NASA/CXC/UCL/W.Dunn et al; Optical, South Pole – NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstädt/Seán Doran; North Pole – NASA/JPL-Caltech/ SwRI/ MSSS/ AmericaSpace.

Jupiter as seen by Juno on October 24, 2017. Image via NASA/ JPL-Caltech/ MSSS/ SwRI/ Kevin M. Gill/ AmericaSpace.

Jupiter as seen by Juno on October 24, 2017. Image via NASA/ JPL-Caltech/ MSSS/ SwRI/ Kevin M. Gill/ AmericaSpace.

Earlier image showing closest-ever view of Jupiter’s Great Red Spot from Juno. Image via NASA/ JPL-Caltech/ MSSS/ SwRI/ Kevin M. Gill/ AmericaSpace.

Juno’s principal investigator Scott Bolton earlier told WIRED:

Almost nothing is as we anticipated. But it’s exciting that Jupiter is so different than we assumed.

Juno was first launched on October 5, 2011, and is the first spacecraft to visit Jupiter since Galileo, which ended its mission on September 21, 2003 by intentionally plummeting into Jupiter’s atmosphere, much like the Cassini probe did at Saturn last September.

Ed Hirst – Juno’s new project manager – has worked on the mission since the beginning, and also worked on the Galileo, Stardust and Genesis missions. He replaces Rick Nybakken, who was recently appointed deputy director for JPL’s Office of Safety and Mission Success.

Juno’s next close flyby of Jupiter will be on December 16, 2017.

Bottom line: New images and info from the Juno mission’s 8th science flyby of Jupiter.

from EarthSky http://ift.tt/2zxq5QA

Star of the week: Achernar

Achernar is flattened because it rotates rapidly

The 9th brightest star in all the heavens, Achernar is a well-known sight to observers in the Southern Hemisphere, but known only by name to the great majority of observers in the Northern Hemisphere. It shines brightly with a magnitude of 0.45 – in other words, as brightly as the brightest stars – but it is so far south on the dome of stars surrounding Earth that it never rises above the horizon from any location north of about 33 degrees N. latitude. Follow the links below to learn more about Achernar, sometimes called the end of the River.

How to see Achernar.

Achernar’s history and mythology.

Science of Achernar.

In a dark sky, you can see that Achernar marks the end of a great stream of stars known to the ancients as a celestial River. This is the constellation Eridanus the River, and Achernar is its brightest star. In fact, the name Achernar means End of the River.

How to see Achernar. For all practical purposes, you must be even further south – around 25 degrees N. latitude – to see Achernar well. That is a line drawn around the entire globe passing through, say, Miami in the U.S. state of Florida and Taipei in China.

Nowhere in North America has it easy, seeing this star. For example, from Key West, Achernar rises only about 8 degrees above the southern horizon. Even farther south, from the southern tip of Hawaii’s Big Island, Achernar never quite makes it to 14 degrees.

And yet, if you are far-enough south, you can see Achernar easily. After all, this star is very bright!

Just as Eridanus marks the end of the River, so the River has a beginning, the star Beta Eridani or Cursa, which itself is easily visible from the northern hemisphere, very near Orion’s brightest star, Rigel.

On most nights of the year, Achernar cannot be seen from anywhere in North America, but around October 20 it skirts the southern horizon around midnight, never getting very high. Then as the months pass, it is seen earlier at night – around 10 p.m. in November, 8 p.m. in December and just after sunset in January. Being far to the south with no bright stars around it, Achernar stands out in its isolation. If you have a dark sky, and are far enough south, you’ll easily see Achernar’s constellation Eridanus swelling up in a great loop under the constellation Orion.

The star Achernar in the constellation Eridanus: End of the river.

Achernar’s history and mythology. The very name Achernar derives from an Arabic phrase meaning the end of the river.

Interestingly, in early classical times the name Achernar was given to the star we now know as Theta Eridani, or Acamar. At that time Acamar was the brightest star of the constellation visible from Greece, and thus was considered the River’s end.

When voyagers discovered the brighter star farther to the south, it became Achernar, and the former Achernar became Acamar.

Apparently both names derive from the same phrase, “Al Ahir al Nahr” according to Richard Hinckley Allen, and mean the same thing.

Science of Achernar. Data from the Hipparcos mission puts Achernar at about 144 light-years away. It is a B3V star, meaning that it belongs to the ranks of “normal” stars known as the “main sequence,” but it is much hotter and brighter than the sun.

In fact, it is nearly 1100 times as bright, visually, as our neighborhood star. Brighter, hotter (and bluer) than the sun, Achernar produces more energy in the non-visible ultraviolet (UV) wavelengths. When you take this into consideration, it pumps out some 3,000 to as much as 5,000 times the solar energy level. The discrepancy is due to an uncertainty in the amount of UV radiation it produces.

Achernar’s mass is 6-8 times that of our sun, and its average diameter is nearly 8-10 times that of the sun. But, while our sun spins on its axis once about every 25 days, Achernar completes one rotation in slightly more than two days, or nearly 15 times faster than our sun. This fast rotation produces an odd, flattened shape, first discovered by the European Southern Observatory’s Very Large Telescope (VLT) in 2003. Up close, Achernar would look more like a blue M&M, while our sun would look more like an orange. Read more about Achernar’s flattened shape from ESO.

This flattening of Achernar makes an exact surface temperature for this star hard to determine, because the flattening actually causes the star’s poles to be hotter than the equator. Estimates range from about 14,500 to 19,300 k (around 26,000 to about 32,000 F).

Achernar’s position is RA: 01h 37m 42.8s, dec: -57° 14′ 12″.

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from EarthSky http://ift.tt/1z49MEY

Achernar is flattened because it rotates rapidly

The 9th brightest star in all the heavens, Achernar is a well-known sight to observers in the Southern Hemisphere, but known only by name to the great majority of observers in the Northern Hemisphere. It shines brightly with a magnitude of 0.45 – in other words, as brightly as the brightest stars – but it is so far south on the dome of stars surrounding Earth that it never rises above the horizon from any location north of about 33 degrees N. latitude. Follow the links below to learn more about Achernar, sometimes called the end of the River.

How to see Achernar.

Achernar’s history and mythology.

Science of Achernar.

In a dark sky, you can see that Achernar marks the end of a great stream of stars known to the ancients as a celestial River. This is the constellation Eridanus the River, and Achernar is its brightest star. In fact, the name Achernar means End of the River.

How to see Achernar. For all practical purposes, you must be even further south – around 25 degrees N. latitude – to see Achernar well. That is a line drawn around the entire globe passing through, say, Miami in the U.S. state of Florida and Taipei in China.

Nowhere in North America has it easy, seeing this star. For example, from Key West, Achernar rises only about 8 degrees above the southern horizon. Even farther south, from the southern tip of Hawaii’s Big Island, Achernar never quite makes it to 14 degrees.

And yet, if you are far-enough south, you can see Achernar easily. After all, this star is very bright!

Just as Eridanus marks the end of the River, so the River has a beginning, the star Beta Eridani or Cursa, which itself is easily visible from the northern hemisphere, very near Orion’s brightest star, Rigel.

On most nights of the year, Achernar cannot be seen from anywhere in North America, but around October 20 it skirts the southern horizon around midnight, never getting very high. Then as the months pass, it is seen earlier at night – around 10 p.m. in November, 8 p.m. in December and just after sunset in January. Being far to the south with no bright stars around it, Achernar stands out in its isolation. If you have a dark sky, and are far enough south, you’ll easily see Achernar’s constellation Eridanus swelling up in a great loop under the constellation Orion.

The star Achernar in the constellation Eridanus: End of the river.

Achernar’s history and mythology. The very name Achernar derives from an Arabic phrase meaning the end of the river.

Interestingly, in early classical times the name Achernar was given to the star we now know as Theta Eridani, or Acamar. At that time Acamar was the brightest star of the constellation visible from Greece, and thus was considered the River’s end.

When voyagers discovered the brighter star farther to the south, it became Achernar, and the former Achernar became Acamar.

Apparently both names derive from the same phrase, “Al Ahir al Nahr” according to Richard Hinckley Allen, and mean the same thing.

Science of Achernar. Data from the Hipparcos mission puts Achernar at about 144 light-years away. It is a B3V star, meaning that it belongs to the ranks of “normal” stars known as the “main sequence,” but it is much hotter and brighter than the sun.

In fact, it is nearly 1100 times as bright, visually, as our neighborhood star. Brighter, hotter (and bluer) than the sun, Achernar produces more energy in the non-visible ultraviolet (UV) wavelengths. When you take this into consideration, it pumps out some 3,000 to as much as 5,000 times the solar energy level. The discrepancy is due to an uncertainty in the amount of UV radiation it produces.

Achernar’s mass is 6-8 times that of our sun, and its average diameter is nearly 8-10 times that of the sun. But, while our sun spins on its axis once about every 25 days, Achernar completes one rotation in slightly more than two days, or nearly 15 times faster than our sun. This fast rotation produces an odd, flattened shape, first discovered by the European Southern Observatory’s Very Large Telescope (VLT) in 2003. Up close, Achernar would look more like a blue M&M, while our sun would look more like an orange. Read more about Achernar’s flattened shape from ESO.

This flattening of Achernar makes an exact surface temperature for this star hard to determine, because the flattening actually causes the star’s poles to be hotter than the equator. Estimates range from about 14,500 to 19,300 k (around 26,000 to about 32,000 F).

Achernar’s position is RA: 01h 37m 42.8s, dec: -57° 14′ 12″.

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Moon and Regulus late night until dawn

Tonight – November 10, 2017 – you’ll have to stay up late, or get up Saturday before dawn, to see the wide waning crescent moon coupling up with Regulus, brightest star in the constellation Leo the Lion. The two luminaries will be highest up for the night around dawn Saturday.

As darkness is giving way to dawn, notice the relationship between the moon, Regulus, and a very bright object in the direction of sunrise. Venus is the brightest planet and brightest object in the sky besides the sun and moon. The lighted portion of the moon will be pointing toward it on Saturday and in the coming mornings. Plus you might glimpse a slightly fainter – but still very bright – planet below Venus. That’ll be Jupiter, which is just now emerging from the dawn after being behind the sun from Earth in late October. And a third planet, faint Mars, is up there, too. See the sky chart below.

And know that Jupiter is now edging higher in the dawn sky! Jupiter and Venus will have a spectacular conjunction on November 13.

Watch as the waning crescent moon swings by 3 morning planets and 1 bright star in the November morning sky. And watch for the Venus-Jupiter conjunction on the morning of November 13.

If you live in southern Alaska, you can watch the moon occult – cover over – Regulus before dawn on November 11, 2017. At Anchorage, Alaska, for instance, Regulus will disappear behind the moon’s illuminated side at 7:07:17 a.m. local time and then reappear from behind the moon’s dark side at 7:25:18 local time.

Click here for more about the November 11 occultation of Regulus.

Worldwide map via IOTA. Everyplace in between the solid white lines sees the lunar occultation of Regulus in a nighttime sky. The very limited area between the blue lines sees the occultation at dawn November 11, and the area of the world in between the dotted red lines has the occultation occurring in a daytime sky on November 11. Click here for more information.

Regulus is the only first-magnitude star to sit almost squarely on the ecliptic, which marks the path of the sun, moon and planets across our sky. In our day and age, the sun’s yearly conjunction with Regulus happens on or near August 23. That’s about two months after the June solstice, or about a month before the September equinox.

Ancient astronomers once thought the sun literally moved through the constellations of the zodiac, while the Earth remained at rest at the center of the universe. Of course, we now know that the Earth revolves around the sun, and that the sun resides at the center of our solar system. We also know that the sun’s apparent daily motion in front of the backdrop stars is really a reflection of Earth revolving around the sun.

The ecliptic is actually the Earth’s orbital plane projected onto the constellations of the zodiac.

Because the planets orbit the sun, and the moon orbits Earth, on nearly the same plane that Earth circles the sun, the moon and planets are always found on or near the ecliptic. If you’re an early bird, waking up before the sun, then use the moon, the star Regulus and the early morning planets Venus and Jupiter to help you envision the ecliptic with the mind’s-eye over the next several days.

When you see Regulus near the moon on the mornings of November 11 and 12, 2017, remember … it’s a much larger star than our sun. Image via The Night Sky Guy.

Bottom line: See the waning crescent moon near Regulus from around midnight until dawn on November 11, 2017. Then watch over the coming mornings as the waning crescent moon sweeps near Regulus and then toward the planets Mars, Venus and jupiter.

EarthSky lunar calendars are cool! They make great gifts. Order now. Going fast!

Donate: Your support means the world to us

from EarthSky http://ift.tt/1l5FblC

Tonight – November 10, 2017 – you’ll have to stay up late, or get up Saturday before dawn, to see the wide waning crescent moon coupling up with Regulus, brightest star in the constellation Leo the Lion. The two luminaries will be highest up for the night around dawn Saturday.

As darkness is giving way to dawn, notice the relationship between the moon, Regulus, and a very bright object in the direction of sunrise. Venus is the brightest planet and brightest object in the sky besides the sun and moon. The lighted portion of the moon will be pointing toward it on Saturday and in the coming mornings. Plus you might glimpse a slightly fainter – but still very bright – planet below Venus. That’ll be Jupiter, which is just now emerging from the dawn after being behind the sun from Earth in late October. And a third planet, faint Mars, is up there, too. See the sky chart below.

And know that Jupiter is now edging higher in the dawn sky! Jupiter and Venus will have a spectacular conjunction on November 13.

Watch as the waning crescent moon swings by 3 morning planets and 1 bright star in the November morning sky. And watch for the Venus-Jupiter conjunction on the morning of November 13.

If you live in southern Alaska, you can watch the moon occult – cover over – Regulus before dawn on November 11, 2017. At Anchorage, Alaska, for instance, Regulus will disappear behind the moon’s illuminated side at 7:07:17 a.m. local time and then reappear from behind the moon’s dark side at 7:25:18 local time.

Click here for more about the November 11 occultation of Regulus.

Worldwide map via IOTA. Everyplace in between the solid white lines sees the lunar occultation of Regulus in a nighttime sky. The very limited area between the blue lines sees the occultation at dawn November 11, and the area of the world in between the dotted red lines has the occultation occurring in a daytime sky on November 11. Click here for more information.

Regulus is the only first-magnitude star to sit almost squarely on the ecliptic, which marks the path of the sun, moon and planets across our sky. In our day and age, the sun’s yearly conjunction with Regulus happens on or near August 23. That’s about two months after the June solstice, or about a month before the September equinox.

Ancient astronomers once thought the sun literally moved through the constellations of the zodiac, while the Earth remained at rest at the center of the universe. Of course, we now know that the Earth revolves around the sun, and that the sun resides at the center of our solar system. We also know that the sun’s apparent daily motion in front of the backdrop stars is really a reflection of Earth revolving around the sun.

The ecliptic is actually the Earth’s orbital plane projected onto the constellations of the zodiac.

Because the planets orbit the sun, and the moon orbits Earth, on nearly the same plane that Earth circles the sun, the moon and planets are always found on or near the ecliptic. If you’re an early bird, waking up before the sun, then use the moon, the star Regulus and the early morning planets Venus and Jupiter to help you envision the ecliptic with the mind’s-eye over the next several days.

When you see Regulus near the moon on the mornings of November 11 and 12, 2017, remember … it’s a much larger star than our sun. Image via The Night Sky Guy.

Bottom line: See the waning crescent moon near Regulus from around midnight until dawn on November 11, 2017. Then watch over the coming mornings as the waning crescent moon sweeps near Regulus and then toward the planets Mars, Venus and jupiter.

EarthSky lunar calendars are cool! They make great gifts. Order now. Going fast!

Donate: Your support means the world to us

from EarthSky http://ift.tt/1l5FblC

The HPV vaccine and cervical screening: how many tests do you need?

It’s coming up on 10 years since the human papillomavirus (HPV) vaccine was first introduced in the UK as a way to curb a cancer-causing infection.

HPV is a common virus. Most adults have it at some point in their lives and the infection usually clears itself up without causing any problems. But for some types of HPV, not clearing the virus can lead to cervical cancer – in fact this is linked to all cases of the disease in the UK.

That’s why the vaccine, which protects against infection with certain forms of the virus, was introduced in 2008 and is routinely offered to girls aged 11-13.

In the next few years those from the first group to be vaccinated as part of the established vaccination programme will receive their first invitation to cervical screening. So a key question researchers have been asking is: can vaccinated women attend cervical screening less frequently?

Now, new research from Cancer Research UK-funded scientists at Queen Mary University of London (QMUL) estimates what the optimum number of screens might be.

The study, published in the International Journal of Cancer, suggests vaccinated women may only need 3 cervical screens in their entire life, rather than the 12 that are standard for all UK women today.

If I’ve been vaccinated, why might I need fewer screens?

Cervical screening looks for abnormal cells in the cervix that can develop into cancer.

This is done by taking a sample of cells, and sending them to a lab where they are tested to see if they are normal (cytology). Testing for HPV is carried out on abnormal cells, to see if they may be becoming cancerous. But soon the order of the tests will switch, and the cells will be tested for HPV infection first, and only those that have the virus will be examined for signs the cells aren’t normal.

This change to HPV primary testing will happen across England, Scotland and Wales by December 2019.

Both the HPV vaccine and cervical screening are intended to prevent cervical cancer. The vaccine works by preventing infections that cause about 70% of cervical cancers. Screening works by finding abnormal cells that sometimes develop into cancer and removing or destroying them.

– Professor Peter Sasieni, QMUL

Testing for HPV first is a better way to screen for cervical cancer than cytology testing, as all cases in the UK are linked to HPV infection. One of the benefits of testing for HPV first is that women who have had the vaccine should need fewer screens because vaccination protects them against the types of HPV most commonly linked to cervical cancer.

“Both the HPV vaccine and cervical screening are intended to prevent cervical cancer,” says Professor Peter Sasieni, lead researcher on the latest study. “The vaccine works by preventing infections that cause about 70% of cervical cancers. Screening works by finding abnormal cells that sometimes develop into cancer and removing or destroying them.”

So if both the vaccine and the screening programme protect against cervical cancer, regularly checking for infection in vaccinated women could be overkill. Because these women are already protected by the vaccine, Sasieni believes that less frequent screening “is enough to prevent the vast majority of cervical cancers”.

In the latest study, Sasieni’s team used data to estimate what would happen if vaccinated women never received any screening, then tested what would happen in their computer model if different screening scenarios were introduced. They compared these numbers to predict the benefits of different frequencies of screening, this showed that a total of 3 screens at ages 30, 40 and 55 offered the same protective benefit as the 12 screens a woman can receive in the current programme.

The vaccine protects against infection with the 2 forms of the virus most strongly linked to cervical cancer, but there are many other types. This is why vaccinated women still benefit from screening – they are just likely to need less of it.

Research like this also addresses a key challenge for screening: how to get the best balance between protection and unnecessary procedures.

I haven’t been vaccinated. Do I still need to go for screening?

Women who haven’t had the vaccine don’t get the protection against HPV infection and so their risk of cervical cancer isn’t reduced. This means that they will need more screens over the course of their lives than vaccinated women to detect abnormal cells and protect against cervical cancer.

But this latest study suggests even these women could get equivalent protection from fewer screens once HPV testing is offered upfront in 2019. Once that change in testing happens, Sasieni’s team think 7 lifetime screens for unvaccinated women would be enough.

“Screening works,” he says, “women who go for regular screening are extremely unlikely to die from cervical cancer.”

“In the future, the HPV infection may become much less common in everyone, because vaccination will have stopped the spread of infection. But we are still a long way from that time.”

So in the meantime, make sure you’re registered with your GP to receive your screening invitation.

Questions that still need to be answered

This study takes lots of information about the protection from the vaccine and the effectiveness of screening to make mathematical predictions about how often a vaccinated woman might need to be screened. But this regularity of screening hasn’t been tested in real life.

The UK governments also haven’t yet made any decisions about changes to the screening programme to account for the protection the vaccine offers, or the impact changing to up-front HPV testing will have on how frequently women are invited.

So, for now, women aged 25-49 will still be invited every 3 years for screening, and every 5 years for those aged 50-64.

We need to think how we change a one-size-fits-all screening programme to a programme that is adapted to different needs

– Professor Peter Sasieni

There are still lots of questions about how to change the screening programme in real life to get the most benefit for everyone, without compromising the protection against cancer. “There is a challenge for the programme of how to adapt rapidly to take advantage of the latest innovation while ensuring that safety is maintained,” says Sasieni.

We now have two groups of women who need different amounts of screening. “We need to think how we change a one-size-fits-all screening programme to a programme that is adapted to different needs,” says Sasieni. This will come with some logistical challenges that need to be considered in any decisions about changes to the screening programme.

Sasieni adds that the screening programme needs to be able to “tailor screening to each woman’s needs”.

We also don’t know how being invited less often might affect the likelihood a woman attends screening at all. If you only get an invitation every 10-15 years, would that make you more or less likely to go? And because women might hypothetically only be attending 3 screens in their lifetime, missing one could have a big impact.

So is this good news or bad news?

While there are still lots of details to be ironed out, the findings of this study are great news for women. They also point to potential benefits for the NHS too, as resources could be saved through less screening.

The bottom line is all women can receive protection from cervical cancer, either through the screening programme alone, or in combination with HPV vaccination. So if you’ve been vaccinated or not, it’s still important to go for screening.

There’s also the distant goal of screening no longer being necessary, because HPV vaccination makes the risk of being infected is so low. This study points to the benefits that vaccination could bring, but some flexibility in the screening programme will be needed soon to help get the maximum benefit for women.

Sophia Lowes is a health information officer at Cancer Research UK

Reference

Landy, R., et al. (2017). What cervical screening is appropriate for women who have been vaccinated against high risk HPV? A simulation study. Int. J. Cancer. DOI: 10.1002/ijc.31094

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

It’s coming up on 10 years since the human papillomavirus (HPV) vaccine was first introduced in the UK as a way to curb a cancer-causing infection.

HPV is a common virus. Most adults have it at some point in their lives and the infection usually clears itself up without causing any problems. But for some types of HPV, not clearing the virus can lead to cervical cancer – in fact this is linked to all cases of the disease in the UK.

That’s why the vaccine, which protects against infection with certain forms of the virus, was introduced in 2008 and is routinely offered to girls aged 11-13.

In the next few years those from the first group to be vaccinated as part of the established vaccination programme will receive their first invitation to cervical screening. So a key question researchers have been asking is: can vaccinated women attend cervical screening less frequently?

Now, new research from Cancer Research UK-funded scientists at Queen Mary University of London (QMUL) estimates what the optimum number of screens might be.

The study, published in the International Journal of Cancer, suggests vaccinated women may only need 3 cervical screens in their entire life, rather than the 12 that are standard for all UK women today.

If I’ve been vaccinated, why might I need fewer screens?

Cervical screening looks for abnormal cells in the cervix that can develop into cancer.

This is done by taking a sample of cells, and sending them to a lab where they are tested to see if they are normal (cytology). Testing for HPV is carried out on abnormal cells, to see if they may be becoming cancerous. But soon the order of the tests will switch, and the cells will be tested for HPV infection first, and only those that have the virus will be examined for signs the cells aren’t normal.

This change to HPV primary testing will happen across England, Scotland and Wales by December 2019.

Both the HPV vaccine and cervical screening are intended to prevent cervical cancer. The vaccine works by preventing infections that cause about 70% of cervical cancers. Screening works by finding abnormal cells that sometimes develop into cancer and removing or destroying them.

– Professor Peter Sasieni, QMUL

Testing for HPV first is a better way to screen for cervical cancer than cytology testing, as all cases in the UK are linked to HPV infection. One of the benefits of testing for HPV first is that women who have had the vaccine should need fewer screens because vaccination protects them against the types of HPV most commonly linked to cervical cancer.

“Both the HPV vaccine and cervical screening are intended to prevent cervical cancer,” says Professor Peter Sasieni, lead researcher on the latest study. “The vaccine works by preventing infections that cause about 70% of cervical cancers. Screening works by finding abnormal cells that sometimes develop into cancer and removing or destroying them.”

So if both the vaccine and the screening programme protect against cervical cancer, regularly checking for infection in vaccinated women could be overkill. Because these women are already protected by the vaccine, Sasieni believes that less frequent screening “is enough to prevent the vast majority of cervical cancers”.

In the latest study, Sasieni’s team used data to estimate what would happen if vaccinated women never received any screening, then tested what would happen in their computer model if different screening scenarios were introduced. They compared these numbers to predict the benefits of different frequencies of screening, this showed that a total of 3 screens at ages 30, 40 and 55 offered the same protective benefit as the 12 screens a woman can receive in the current programme.

The vaccine protects against infection with the 2 forms of the virus most strongly linked to cervical cancer, but there are many other types. This is why vaccinated women still benefit from screening – they are just likely to need less of it.

Research like this also addresses a key challenge for screening: how to get the best balance between protection and unnecessary procedures.

I haven’t been vaccinated. Do I still need to go for screening?

Women who haven’t had the vaccine don’t get the protection against HPV infection and so their risk of cervical cancer isn’t reduced. This means that they will need more screens over the course of their lives than vaccinated women to detect abnormal cells and protect against cervical cancer.

But this latest study suggests even these women could get equivalent protection from fewer screens once HPV testing is offered upfront in 2019. Once that change in testing happens, Sasieni’s team think 7 lifetime screens for unvaccinated women would be enough.

“Screening works,” he says, “women who go for regular screening are extremely unlikely to die from cervical cancer.”

“In the future, the HPV infection may become much less common in everyone, because vaccination will have stopped the spread of infection. But we are still a long way from that time.”

So in the meantime, make sure you’re registered with your GP to receive your screening invitation.

Questions that still need to be answered

This study takes lots of information about the protection from the vaccine and the effectiveness of screening to make mathematical predictions about how often a vaccinated woman might need to be screened. But this regularity of screening hasn’t been tested in real life.

The UK governments also haven’t yet made any decisions about changes to the screening programme to account for the protection the vaccine offers, or the impact changing to up-front HPV testing will have on how frequently women are invited.

So, for now, women aged 25-49 will still be invited every 3 years for screening, and every 5 years for those aged 50-64.

We need to think how we change a one-size-fits-all screening programme to a programme that is adapted to different needs

– Professor Peter Sasieni

There are still lots of questions about how to change the screening programme in real life to get the most benefit for everyone, without compromising the protection against cancer. “There is a challenge for the programme of how to adapt rapidly to take advantage of the latest innovation while ensuring that safety is maintained,” says Sasieni.

We now have two groups of women who need different amounts of screening. “We need to think how we change a one-size-fits-all screening programme to a programme that is adapted to different needs,” says Sasieni. This will come with some logistical challenges that need to be considered in any decisions about changes to the screening programme.

Sasieni adds that the screening programme needs to be able to “tailor screening to each woman’s needs”.

We also don’t know how being invited less often might affect the likelihood a woman attends screening at all. If you only get an invitation every 10-15 years, would that make you more or less likely to go? And because women might hypothetically only be attending 3 screens in their lifetime, missing one could have a big impact.

So is this good news or bad news?

While there are still lots of details to be ironed out, the findings of this study are great news for women. They also point to potential benefits for the NHS too, as resources could be saved through less screening.

The bottom line is all women can receive protection from cervical cancer, either through the screening programme alone, or in combination with HPV vaccination. So if you’ve been vaccinated or not, it’s still important to go for screening.

There’s also the distant goal of screening no longer being necessary, because HPV vaccination makes the risk of being infected is so low. This study points to the benefits that vaccination could bring, but some flexibility in the screening programme will be needed soon to help get the maximum benefit for women.

Sophia Lowes is a health information officer at Cancer Research UK

Reference

Landy, R., et al. (2017). What cervical screening is appropriate for women who have been vaccinated against high risk HPV? A simulation study. Int. J. Cancer. DOI: 10.1002/ijc.31094

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

What makes zombie ants obey

Here’s a dead zombie ant, a tropical carpenter ant in Thailand, killed by a parasitic fungus. On its head is a fungal fruiting body containing spores that will later infect other ants. Image via David P. Hughes, Penn State University.

Researchers at Penn State University today (November 8, 2017) released new information about one of Earth’s weirdest natural phenomena: zombie ants. These are carpenter ants in tropical locations, infiltrated and controlled by Ophiocordyceps unilateralis sensu lato, sometimes called zombie ant fungus. This fungal body-snatcher forces ants to a forest understory and compels them to climb vegetation and bite into the underside of leaves or twigs, where the ants die. The invasion culminates with the sprouting of a spore-laden fruiting body from a dead ant’s head. The fungus thereby benefits because infectious spores are released onto the ground below, where they can infect other foraging ants. The new research shows that the fungal parasite accomplishes all this without infecting the ants’ brains.

Instead, the new work shows, the zombie ant fungus surrounds and invades muscle fibers throughout the ant’s body. The study showed O. unilateralis s.l. cells present in a host ant’s head, thorax, abdomen and legs. What’s more, a large proportion of these fungal cells appeared to be connected to each other. They seemed to form a 3-D network, which, the researchers believe, might collectively control the ant’s behavior.

Maridel Fredericksen (@delfreddy on Twitter) was a master’s degree student in entomology at Penn State and is now a doctoral candidate at the University of Basel Zoological Institute, Switzerland. She’s lead author on the new research. Her team first infected ants with O. unilateralis s.l., then used serial block-face scanning-electron microscopy to create 3-D visualizations, with the goal of determining the distribution, abundance and interactions of the fungi inside the bodies of the ants. David Hughes, associate professor of entomology and biology at Penn State – known for his prior studies of zombie ants – said the use of this technology let the researchers make a breakthrough in understanding why zombie ants behave as they do. He said:

We found that a high percentage of the cells in a host were fungal cells. In essence, these manipulated animals were a fungus in ants’ clothing.

The research showed that, although fungal cells were concentrated directly outside the brain, no fungal cells were found inside the ants’ brains by these researchers. Hughes said:

Normally in animals, behavior is controlled by the brain sending signals to the muscles, but our results suggest that the parasite is controlling host behavior peripherally. Almost like a puppeteer pulls the strings to make a marionette move, the fungus controls the ant’s muscles to manipulate the host’s legs and mandibles.

This image is a 3-D reconstruction of an ant mandible adductor muscle (red) surrounded by a network of fungal cells (yellow). Image via Hughes Laboratory / Penn State.

The researchers said that, although the ant’s brain isn’t invaded by fungal cells, previous work has shown that the brain might be chemically altered by the parasite. Hughes said:

We hypothesize that the fungus may be preserving the brain so the host can survive until it performs its final biting behavior — that critical moment for fungal reproduction. But we need to conduct additional research to determine the brain’s role and how much control the fungus exercises over it.

When ants become walking dead. This ant is being manipulated by zombie ant fungus, biting onto the underside of a twig — its last act before dying and becoming a platform for fungal reproduction. Image via Kim Fleming/ Penn State.

Bottom line: Ophiocordyceps unilateralis sensu lato, sometimes called zombie ant fungus, doesn’t invade the brains of ants. Instead, it invades their whole bodies, forming an interconnected 3-D network that forces the ant to do its bidding.

Via Penn State

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

Here’s a dead zombie ant, a tropical carpenter ant in Thailand, killed by a parasitic fungus. On its head is a fungal fruiting body containing spores that will later infect other ants. Image via David P. Hughes, Penn State University.

Researchers at Penn State University today (November 8, 2017) released new information about one of Earth’s weirdest natural phenomena: zombie ants. These are carpenter ants in tropical locations, infiltrated and controlled by Ophiocordyceps unilateralis sensu lato, sometimes called zombie ant fungus. This fungal body-snatcher forces ants to a forest understory and compels them to climb vegetation and bite into the underside of leaves or twigs, where the ants die. The invasion culminates with the sprouting of a spore-laden fruiting body from a dead ant’s head. The fungus thereby benefits because infectious spores are released onto the ground below, where they can infect other foraging ants. The new research shows that the fungal parasite accomplishes all this without infecting the ants’ brains.

Instead, the new work shows, the zombie ant fungus surrounds and invades muscle fibers throughout the ant’s body. The study showed O. unilateralis s.l. cells present in a host ant’s head, thorax, abdomen and legs. What’s more, a large proportion of these fungal cells appeared to be connected to each other. They seemed to form a 3-D network, which, the researchers believe, might collectively control the ant’s behavior.

Maridel Fredericksen (@delfreddy on Twitter) was a master’s degree student in entomology at Penn State and is now a doctoral candidate at the University of Basel Zoological Institute, Switzerland. She’s lead author on the new research. Her team first infected ants with O. unilateralis s.l., then used serial block-face scanning-electron microscopy to create 3-D visualizations, with the goal of determining the distribution, abundance and interactions of the fungi inside the bodies of the ants. David Hughes, associate professor of entomology and biology at Penn State – known for his prior studies of zombie ants – said the use of this technology let the researchers make a breakthrough in understanding why zombie ants behave as they do. He said:

We found that a high percentage of the cells in a host were fungal cells. In essence, these manipulated animals were a fungus in ants’ clothing.

The research showed that, although fungal cells were concentrated directly outside the brain, no fungal cells were found inside the ants’ brains by these researchers. Hughes said:

Normally in animals, behavior is controlled by the brain sending signals to the muscles, but our results suggest that the parasite is controlling host behavior peripherally. Almost like a puppeteer pulls the strings to make a marionette move, the fungus controls the ant’s muscles to manipulate the host’s legs and mandibles.

This image is a 3-D reconstruction of an ant mandible adductor muscle (red) surrounded by a network of fungal cells (yellow). Image via Hughes Laboratory / Penn State.

The researchers said that, although the ant’s brain isn’t invaded by fungal cells, previous work has shown that the brain might be chemically altered by the parasite. Hughes said:

We hypothesize that the fungus may be preserving the brain so the host can survive until it performs its final biting behavior — that critical moment for fungal reproduction. But we need to conduct additional research to determine the brain’s role and how much control the fungus exercises over it.

When ants become walking dead. This ant is being manipulated by zombie ant fungus, biting onto the underside of a twig — its last act before dying and becoming a platform for fungal reproduction. Image via Kim Fleming/ Penn State.

Bottom line: Ophiocordyceps unilateralis sensu lato, sometimes called zombie ant fungus, doesn’t invade the brains of ants. Instead, it invades their whole bodies, forming an interconnected 3-D network that forces the ant to do its bidding.

Via Penn State

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

Pleiades star cluster, aka Seven Sisters

The Pleiades – aka the Seven Sisters – captured by Greg Hogan in Kathleen, Georgia on October 31, 2016.

The Pleiades star cluster – also known as the Seven Sisters or M45 – is visible from virtually every place that humanity inhabits Earth’s globe. It can be seen from as far north as the north pole, and farther south than the southernmost tip of South America. It looks like a tiny misty dipper of stars. Follow the links below to learn more about the Pleiades.

How to see the Pleiades.

Legend of the Lost Pleiad.

Pleiades as calendar, in history and in modern science.

Tom Wildoner in Weatherly, Pennsylvania captured this image on October 31, 2016. He wrote: “It shows the Seven Sisters, Pleiades star cluster rising in the east behind some maple trees still sporting some late leaves.”

How to see the Pleiades. If you’re familiar with the famous constellation Orion, it can help you be sure you’ve found the Pleiades. The image at right shows Orion at the bottom left. See the three stars in a row? That’s Orion’s Belt. Draw a line through the three stars of Orion’s Belt to the right – and you come to a V-shaped pattern of stars with a bright star in its midst. The V-shaped pattern is the Face of Taurus the Bull. The bright star in the V – called Aldebaran – depicts the Bull’s Eye. A bit past Aldebaran, you’ll see the Pleiades cluster, which marks the Bull’s Shoulder. In our image, the Pleiades cluster is at the top right.

The Pleiades, Hyades and Orion.

Aldebaran, Arabic for follower, is thought to be in reference to this star forever chasing the Pleiades across the heavens. As a general rule, the Pleiades cluster rises into the eastern sky before Aldebaran rises, and sets in the west before Aldebaran sets. The only exception to this rule happens at far southern latitudes – like at South America’s Tierra del Fuego – where the Pleiades rise a short while after Aldebaran rises.

In our Northern Hemispheres skies, the Pleiades cluster is associated with the winter season. It’s easy to imagine this misty patch of icy-blue suns as hoarfrost clinging to the dome of night. Frosty November is often called the month of the Pleiades, because it’s at this time that the Pleiades shine from dusk until dawn. But you can see the Pleiades cluster in the evening sky well into April.

The Lost Pleiad, a painting by French artist William-Adolphe Bouguereau (1825-1905). Image via Wikimedia Commons.

Legend of the Lost Pleiad. Most people see 6, not 7, Pleiades stars in a dark country sky.

However, the story about the lost 7th Pleiad harbors a universal theme. The astronomer Robert Burnham Jr. finds the lost Pleaid myth prevalent in the star lore of European, African, Asian, Indonesian, Native American and Aboriginal Australian populations.

Moreover, Burnham suggests the “lost Pleiad” may have basis in fact. After all, modern astronomy has found that the 7th brightest Pleiades star – Pleione – is a complicated and hard-to-understand “shell star” that goes through numerous permutations. These changes cause this star to vary in brightness.

Plus people with exceptional eyesight have been known to see many more stars in the Pleiades cluster. Claims go up as high as 20 stars. Miss Agnes Clerke reports that Maestlin, the tutor of Kepler, mapped out 11 Pleiades stars before the invention of the telescope.

However, you must be willing to spend time under a dark, moonless sky to see more than 6 or 7 Pleaides stars. Stephen O’Meara, a dark-sky connoisseur, claims that eyes dark-adapted for 30 minutes are 6 times more sensitive to light than eyes dark-adapted for 15 minutes. The surest way to see additional Pleiades stars is to look at this cluster through binoculars or low power in a telescope.

Pleiades as calendar, in history and in modern science. Historically, the Pleiades have served as a calendar for many civilizations. The Greek name “Pleiades” probably means “to sail.” In the ancient Mediterranean world, the day that the Pleaides cluster first appeared in the morning sky before sunrise announced the opening of the navigation season.

The modern-day festival of Halloween originates from an old Druid rite that coincided with the midnight culmination of the Pleiades cluster. It was believed that the veil dividing the living from the dead is at its thinnest when the Pleaides culminates – reaches its highest point in the sky – at midnight.

On a lighter note, the Zuni of New Mexico call the Pleiades the “Seed Stars,” because this cluster’s disappearance in the evening sky every spring signals the seed-planting season.

In both myth and science, the Pleiades are considered to be sibling stars. Modern astronomers say the Pleiades stars were born from the same cloud of gas and dust some 100 million years ago. This gravitationally bound cluster of several hundred stars looms some 430 light-years distant, and these sibling stars drift through space together at about 25 miles per second. Many of these Pleiades stars shine hundreds of times more brightly than our sun.

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

Bottom line: November is often called the month of the Pleiades – or Seven Sisters – because it’s at this time that the Pleiades shine from dusk until dawn.

from EarthSky http://ift.tt/1B8AXQp

The Pleiades – aka the Seven Sisters – captured by Greg Hogan in Kathleen, Georgia on October 31, 2016.

The Pleiades star cluster – also known as the Seven Sisters or M45 – is visible from virtually every place that humanity inhabits Earth’s globe. It can be seen from as far north as the north pole, and farther south than the southernmost tip of South America. It looks like a tiny misty dipper of stars. Follow the links below to learn more about the Pleiades.

How to see the Pleiades.

Legend of the Lost Pleiad.

Pleiades as calendar, in history and in modern science.

Tom Wildoner in Weatherly, Pennsylvania captured this image on October 31, 2016. He wrote: “It shows the Seven Sisters, Pleiades star cluster rising in the east behind some maple trees still sporting some late leaves.”

How to see the Pleiades. If you’re familiar with the famous constellation Orion, it can help you be sure you’ve found the Pleiades. The image at right shows Orion at the bottom left. See the three stars in a row? That’s Orion’s Belt. Draw a line through the three stars of Orion’s Belt to the right – and you come to a V-shaped pattern of stars with a bright star in its midst. The V-shaped pattern is the Face of Taurus the Bull. The bright star in the V – called Aldebaran – depicts the Bull’s Eye. A bit past Aldebaran, you’ll see the Pleiades cluster, which marks the Bull’s Shoulder. In our image, the Pleiades cluster is at the top right.

The Pleiades, Hyades and Orion.

Aldebaran, Arabic for follower, is thought to be in reference to this star forever chasing the Pleiades across the heavens. As a general rule, the Pleiades cluster rises into the eastern sky before Aldebaran rises, and sets in the west before Aldebaran sets. The only exception to this rule happens at far southern latitudes – like at South America’s Tierra del Fuego – where the Pleiades rise a short while after Aldebaran rises.

In our Northern Hemispheres skies, the Pleiades cluster is associated with the winter season. It’s easy to imagine this misty patch of icy-blue suns as hoarfrost clinging to the dome of night. Frosty November is often called the month of the Pleiades, because it’s at this time that the Pleiades shine from dusk until dawn. But you can see the Pleiades cluster in the evening sky well into April.

The Lost Pleiad, a painting by French artist William-Adolphe Bouguereau (1825-1905). Image via Wikimedia Commons.

Legend of the Lost Pleiad. Most people see 6, not 7, Pleiades stars in a dark country sky.

However, the story about the lost 7th Pleiad harbors a universal theme. The astronomer Robert Burnham Jr. finds the lost Pleaid myth prevalent in the star lore of European, African, Asian, Indonesian, Native American and Aboriginal Australian populations.

Moreover, Burnham suggests the “lost Pleiad” may have basis in fact. After all, modern astronomy has found that the 7th brightest Pleiades star – Pleione – is a complicated and hard-to-understand “shell star” that goes through numerous permutations. These changes cause this star to vary in brightness.

Plus people with exceptional eyesight have been known to see many more stars in the Pleiades cluster. Claims go up as high as 20 stars. Miss Agnes Clerke reports that Maestlin, the tutor of Kepler, mapped out 11 Pleiades stars before the invention of the telescope.

However, you must be willing to spend time under a dark, moonless sky to see more than 6 or 7 Pleaides stars. Stephen O’Meara, a dark-sky connoisseur, claims that eyes dark-adapted for 30 minutes are 6 times more sensitive to light than eyes dark-adapted for 15 minutes. The surest way to see additional Pleiades stars is to look at this cluster through binoculars or low power in a telescope.

Pleiades as calendar, in history and in modern science. Historically, the Pleiades have served as a calendar for many civilizations. The Greek name “Pleiades” probably means “to sail.” In the ancient Mediterranean world, the day that the Pleaides cluster first appeared in the morning sky before sunrise announced the opening of the navigation season.

The modern-day festival of Halloween originates from an old Druid rite that coincided with the midnight culmination of the Pleiades cluster. It was believed that the veil dividing the living from the dead is at its thinnest when the Pleaides culminates – reaches its highest point in the sky – at midnight.

On a lighter note, the Zuni of New Mexico call the Pleiades the “Seed Stars,” because this cluster’s disappearance in the evening sky every spring signals the seed-planting season.

In both myth and science, the Pleiades are considered to be sibling stars. Modern astronomers say the Pleiades stars were born from the same cloud of gas and dust some 100 million years ago. This gravitationally bound cluster of several hundred stars looms some 430 light-years distant, and these sibling stars drift through space together at about 25 miles per second. Many of these Pleiades stars shine hundreds of times more brightly than our sun.

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

Bottom line: November is often called the month of the Pleiades – or Seven Sisters – because it’s at this time that the Pleiades shine from dusk until dawn.

from EarthSky http://ift.tt/1B8AXQp

Today in science: Carl Sagan’s birthday

It was Carl Sagan who said, “We’re made of star stuff. We are a way for the cosmos to know itself.” Image via Dab’s Magazine.

November 9, 1934. Today is the anniversary of the birth of astronomer and astronomy popularizer extraordinaire Carl Sagan. Most of us are familiar with this late American astronomer through his books and television series Cosmos. Sagan also contributed greatly to the field of planetary science and monumentally – perhaps immortally – to the American space program.

Carl Edward Sagan was born on November 9, 1934 in Brooklyn, New York. He studied physics at the University of Chicago and earned his doctorate in astronomy and astrophysics in 1960.

In the 1960s, one of Sagan’s earliest works in professional astronomical research shed light on the atmospheres of our solar system’s planets. The atmospheres of Mars and Venus, for example, are known now to resemble that of Earth. But in Sagan’s day, scientists were still trying to understand how come Mars could be so cold while Venus is so hot. Sagan successfully confirmed that Venus could be a greenhouse furnace by using data from tables for steam boiler engineering.

Around this same time, Sagan became interested in the search for extraterrestrial intelligence (SETI) and contributed much to it. He proved that the building blocks of life could be easily created by exposing simple chemicals to UV light. In 1966, he helped I. S. Shklovskii, a Soviet astronomer and astrophysicist, revise and expand his classic book on extraterrestrial life, Intelligent Life in the Universe.

In 1971, Sagan was denied tenure at Harvard University; some speculated it was due to his controversial opinions on extraterrestrial intelligence. He went on to become a professor at Cornell University in Ithaca, New York, where he spent the rest of his professional career.

Sagan contributed mightily to the U.S. space program. Among other things, he briefed astronauts before their trip to the moon, and he was part of the Mariner, Viking, Galileo, and Voyager space missions. In the Viking missions, for example – two probes sent to explore Mars in the 1970s – he advised on the choice of ideal landing sites.

Carl Sagan poses with a model of the Viking lander in Death Valley, California. Image via NASA.

But, in addition to his books and the Cosmos television series, it’s Sagan’s actual messages to the cosmos – placed aboard the first spacecraft designed to leave our solar system, on the Pioneer and Voyager missions – for which he’s most remembered.

The original idea for the Pioneer plaques – a pair of gold-anodized aluminium plaques carrying messages from humankind, placed aboard the 1972 Pioneer 10 and 1973 Pioneer 11 spacecraft – originally came from journalist and consultant Eric Burgess. He approached Sagan about it, and NASA agreed to it and gave Sagan three weeks to prepare a message. Together with astronomer Frank Drake, who formulated the famous Drake Equation (a way of estimating the number of intelligent civilizations in our Milky Way galaxy), Sagan designed the plaque, with artwork prepared by his wife at the time, Linda Salzman Sagan.

The Pioneers and the plaques they carry are now billions of miles from Earth (but still within our sun’s influence). But eventually they’ll cross out of the sun’s influence, into the realm between the stars.

A Pioneer plaque, which Carl Sagan helped design and place aboard the 1st 2 spacecraft ever to leave Earth for interstellar space, via Wikimedia Commons.

Later in that same decade, in the late 1970s, Sagan and his wife-to-be, Ann Druyan, contributed to the design of yet-other message from humankind to outer space. The Voyager probes were launched in 1977, and they both carry what is known as a Voyager Golden Record. Each Golden Record contains 116 images that depict historical scientific works and humans performing mundane activities, plus music from artists such as Bach, Mozart, and Chuck Berry, an hour-long record of Ann Druyan’s brainwaves, and greetings in 55 languages.

Click here for a list of all the material on the Golden Records.

Listen to the entire musical selection of the Golden Records.

The Voyagers were launched later, but traveled faster than the Pioneers. Voyager 1 is now considered to be in interstellar space. It is the farthest object from Earth that is human-made. Voyager 2 is somewhat closer and is still in an outer region of our sun’s influence, known as the heliosheath.

Click here to see where the Voyager probes are, in real time.

The Golden Record, NASA/JPL, via Wikimedia Commons.

During the 1980s, Sagan encouraged nuclear disarmament and was one of the five authors of the concept of nuclear winter, which describes the aftermath of a nuclear war. The work showed once and for all that, in a nuclear war, no one would win. It’s hard to estimate the importance of this work to the global consciousness of the time, but it’s perhaps no accident that the cold war ended not long afterwards.

Carl Sagan remained at Cornell until his death on December 20, 1996 at age 62 from pneumonia.

Over the course of his life, Carl Sagan wrote more than 600 professional astronomical research papers and 20 books. He was an inspiration to many. He inspired and continues to inspire many young scientists to thread the path of astronomy and astronomical communication. He encouraged scientific responsibility by promoting nuclear disarmament. His work in science outreach encouraged science literacy not only among Americans, but among the entire human race. He was very quotable and said, among many other wonderful things:

Somewhere, something incredible is waiting to be known.

Do you remember him? Do you remember his words and the sound of his voice? Listen and remember, via the video below.

Bottom line: Carl Sagan was born on November 9, 1934. He is most remembered for his efforts in popularizing science through his books, for his television series Cosmos and for his messages to the cosmos placed on the Pioneer and Voyager spacecraft.

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

It was Carl Sagan who said, “We’re made of star stuff. We are a way for the cosmos to know itself.” Image via Dab’s Magazine.

November 9, 1934. Today is the anniversary of the birth of astronomer and astronomy popularizer extraordinaire Carl Sagan. Most of us are familiar with this late American astronomer through his books and television series Cosmos. Sagan also contributed greatly to the field of planetary science and monumentally – perhaps immortally – to the American space program.

Carl Edward Sagan was born on November 9, 1934 in Brooklyn, New York. He studied physics at the University of Chicago and earned his doctorate in astronomy and astrophysics in 1960.

In the 1960s, one of Sagan’s earliest works in professional astronomical research shed light on the atmospheres of our solar system’s planets. The atmospheres of Mars and Venus, for example, are known now to resemble that of Earth. But in Sagan’s day, scientists were still trying to understand how come Mars could be so cold while Venus is so hot. Sagan successfully confirmed that Venus could be a greenhouse furnace by using data from tables for steam boiler engineering.

Around this same time, Sagan became interested in the search for extraterrestrial intelligence (SETI) and contributed much to it. He proved that the building blocks of life could be easily created by exposing simple chemicals to UV light. In 1966, he helped I. S. Shklovskii, a Soviet astronomer and astrophysicist, revise and expand his classic book on extraterrestrial life, Intelligent Life in the Universe.

In 1971, Sagan was denied tenure at Harvard University; some speculated it was due to his controversial opinions on extraterrestrial intelligence. He went on to become a professor at Cornell University in Ithaca, New York, where he spent the rest of his professional career.

Sagan contributed mightily to the U.S. space program. Among other things, he briefed astronauts before their trip to the moon, and he was part of the Mariner, Viking, Galileo, and Voyager space missions. In the Viking missions, for example – two probes sent to explore Mars in the 1970s – he advised on the choice of ideal landing sites.

Carl Sagan poses with a model of the Viking lander in Death Valley, California. Image via NASA.

But, in addition to his books and the Cosmos television series, it’s Sagan’s actual messages to the cosmos – placed aboard the first spacecraft designed to leave our solar system, on the Pioneer and Voyager missions – for which he’s most remembered.

The original idea for the Pioneer plaques – a pair of gold-anodized aluminium plaques carrying messages from humankind, placed aboard the 1972 Pioneer 10 and 1973 Pioneer 11 spacecraft – originally came from journalist and consultant Eric Burgess. He approached Sagan about it, and NASA agreed to it and gave Sagan three weeks to prepare a message. Together with astronomer Frank Drake, who formulated the famous Drake Equation (a way of estimating the number of intelligent civilizations in our Milky Way galaxy), Sagan designed the plaque, with artwork prepared by his wife at the time, Linda Salzman Sagan.

The Pioneers and the plaques they carry are now billions of miles from Earth (but still within our sun’s influence). But eventually they’ll cross out of the sun’s influence, into the realm between the stars.

A Pioneer plaque, which Carl Sagan helped design and place aboard the 1st 2 spacecraft ever to leave Earth for interstellar space, via Wikimedia Commons.

Later in that same decade, in the late 1970s, Sagan and his wife-to-be, Ann Druyan, contributed to the design of yet-other message from humankind to outer space. The Voyager probes were launched in 1977, and they both carry what is known as a Voyager Golden Record. Each Golden Record contains 116 images that depict historical scientific works and humans performing mundane activities, plus music from artists such as Bach, Mozart, and Chuck Berry, an hour-long record of Ann Druyan’s brainwaves, and greetings in 55 languages.

Click here for a list of all the material on the Golden Records.

Listen to the entire musical selection of the Golden Records.

The Voyagers were launched later, but traveled faster than the Pioneers. Voyager 1 is now considered to be in interstellar space. It is the farthest object from Earth that is human-made. Voyager 2 is somewhat closer and is still in an outer region of our sun’s influence, known as the heliosheath.

Click here to see where the Voyager probes are, in real time.

The Golden Record, NASA/JPL, via Wikimedia Commons.

During the 1980s, Sagan encouraged nuclear disarmament and was one of the five authors of the concept of nuclear winter, which describes the aftermath of a nuclear war. The work showed once and for all that, in a nuclear war, no one would win. It’s hard to estimate the importance of this work to the global consciousness of the time, but it’s perhaps no accident that the cold war ended not long afterwards.

Carl Sagan remained at Cornell until his death on December 20, 1996 at age 62 from pneumonia.

Over the course of his life, Carl Sagan wrote more than 600 professional astronomical research papers and 20 books. He was an inspiration to many. He inspired and continues to inspire many young scientists to thread the path of astronomy and astronomical communication. He encouraged scientific responsibility by promoting nuclear disarmament. His work in science outreach encouraged science literacy not only among Americans, but among the entire human race. He was very quotable and said, among many other wonderful things:

Somewhere, something incredible is waiting to be known.

Do you remember him? Do you remember his words and the sound of his voice? Listen and remember, via the video below.

Bottom line: Carl Sagan was born on November 9, 1934. He is most remembered for his efforts in popularizing science through his books, for his television series Cosmos and for his messages to the cosmos placed on the Pioneer and Voyager spacecraft.

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