Weekly Space Hangout – Sept 30, 2016: Please Don’t Break Our Hearts Elon Musk

Host: Fraser Cain (@fcain)

Guests:

Morgan Rehnberg (MorganRehnberg.com / @MorganRehnberg)
Dave Dickinson (www.astroguyz.com / @astroguyz)
Kimberly Cartier ( KimberlyCartier.org / @AstroKimCartier )
Yoav Landsman (@MasaCritit)

Their stories this week:

Elon’s Mars fantasy

Hidden spiral arms in planet-forming disk

First extragalactic gamma-ray binary

China’s new 500 metre radio scope

Rosetta’s last plunge

We’ve had an abundance of news stories for the past few months, and not enough time to get to them all. So we are now using a tool called Trello to submit and vote on stories we would like to see covered each week, and then Fraser will be selecting the stories from there. Here is the link to the Trello WSH page (http://bit.ly/WSHVote), which you can see without logging in. If you’d like to vote, just create a login and help us decide what to cover!

If you would like to join the Weekly Space Hangout Crew, visit their site here and sign up. They’re a great team who can help you join our online discussions!

If you would like to sign up for the AstronomyCast Solar Eclipse Escape, where you can meet Fraser and Pamela, plus WSH Crew and other fans, visit our site linked above and sign up!

We record the Weekly Space Hangout every Friday at 12:00 pm Pacific / 3:00 pm Eastern. You can watch us live on Universe Today, or the Universe Today YouTube page.

Journey’s End: Comet Crash for Rosetta Mission Finale

With a soft “awwww” from the mission team in the control center in Darmstadt, Germany, the signal from the Rosetta spacecraft faded, indicating the end of its journey. Rosetta made a controlled impact onto Comet 67P/Churyumov–Gerasimenko, sending back incredible close-up images during descent, after two years of investigations at the comet.

“Farewell Rosetta. You have done the job. That was space science at its best,” said Patrick Martin, Rosetta mission manager.

Rosetta’s final resting spot appears to be in a region of active pits in the Ma’at region on the two-lobed, duck-shaped comet.

The information collected during the descent – as well as during the entire mission – will be studied for years. So even though the video below about the mission’s end will likely bring a tear to your eye, rest assured the mission will continue as the science from Rosetta is just getting started.

“Rosetta has entered the history books once again,” says Johann-Dietrich Wörner, ESA’s Director General. “Today we celebrate the success of a game-changing mission, one that has surpassed all our dreams and expectations, and one that continues ESA’s legacy of ‘firsts’ at comets.”

Launched in 2004, Rosetta traveled nearly 8 billion kilometers and its journey included three Earth flybys and one at Mars, and two asteroid encounters. It arrived at the comet in August 2014 after being in hibernation for 31 months.

After becoming the first spacecraft to orbit a comet, it deployed the Philae lander in November 2014. Philae sent back data for a few days before succumbing to a power loss after it unfortunately landed in a crevice and its solar panels couldn’t receive sunlight. But Rosetta continued to monitor the comet’s evolution as it made its closest approach and then moved away from the Sun. However, now Rosetta and the comet are too far away from the Sun for the spacecraft to receive enough power to continue operations.

“We’ve operated in the harsh environment of the comet for 786 days, made a number of dramatic flybys close to its surface, survived several unexpected outbursts from the comet, and recovered from two spacecraft ‘safe modes’,” said operations manager Sylvain Lodiot. “The operations in this final phase have challenged us more than ever before, but it’s a fitting end to Rosetta’s incredible adventure to follow its lander down to the comet.”

Compilation of the brightest outbursts seen at Comet 67P/Churyumov–Gerasimenko by Rosetta’s OSIRIS narrow-angle camera and Navigation Camera between July and September 2015. Credit: OSIRIS: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA; NavCam: ESA/Rosetta/NavCam – CC BY-SA IGO 3.0.
Compilation of the brightest outbursts seen at Comet 67P/Churyumov–Gerasimenko by Rosetta’s OSIRIS narrow-angle camera and Navigation Camera between July and September 2015. Credit: OSIRIS: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA; NavCam: ESA/Rosetta/NavCam – CC BY-SA IGO 3.0.

Rosetta’s Legacy and Discoveries

Of its many discoveries, Rosetta’s close-up views of the curiously-shaped Comet 67P have already changed some long-held ideas about comets. With the discovery of water with a different ‘flavor’ to that of Earth’s oceans, it appears that Earth impacts of comets like 67P/Churyumov–Gerasimenko may not have delivered as much of Earth’s water as previously thought.

From Philae, it was determined that even though organic molecules exist on the comet, they might not be the kind that can deliver the chemical prerequisites for life. However, a later study revealed that complex organic molecules exist in the dust surrounding the comet, such as the amino acid glycine, which is commonly found in proteins, and phosphorus, a key component of DNA and cell membranes. This reinforces the idea that the basic building blocks may have been delivered to Earth from an early bombardment of comets.

Rosetta’s long-term monitoring has also shown just how important the comet’s shape is in influencing its seasons, in moving dust across its surface, and in explaining the variations measured in the density and composition of the comet’s coma.

And because of Rosetta’s proximity to the comet, we all went along for the ride as the spacecraft captured views of what happens as a comet comes close to the Sun, with ice sublimating and dusty jets exploding from the surface.

Studies of the comet show it formed in a very cold region of the protoplanetary nebula when the Solar System was forming more than 4.5 billion years ago. The comet’s two lobes likely formed independently, but came together later in a low-speed collision.

“Just as the Rosetta Stone after which this mission was named was pivotal in understanding ancient language and history, the vast treasure trove of Rosetta spacecraft data is changing our view on how comets and the Solar System formed,” said project scientist Matt Taylor.

Sequence of images captured by Rosetta during its descent to the surface of Comet 67P/C-G on September 30, 2016. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA.
Sequence of images captured by Rosetta during its descent to the surface of Comet 67P/C-G on September 30, 2016. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA.

Journey’s End

During the final hours of the mission on Friday morning, the instrument teams watched the data stream in and followed the spacecraft as it moved closer to its targeted touchdown location on the “head” of the 4km-wide comet. The pitted region where Rosetta landed appear to be the places where 67P ejects gas and dust into space, and so Rosetta’s swan song will provide more insight into the comet’s icy jets.

“With the decision to take Rosetta down to the comet’s surface, we boosted the scientific return of the mission through this last, once-in-a-lifetime operation,” said Martin. ““It’s a bittersweet ending, but … Rosetta’s destiny was set a long time ago. But its superb achievements will now remain for posterity and be used by the next generation of young scientists and engineers around the world.”

See more stunning, final images in Bob King’s compilation article, and we bid Rosetta farewell with this lovely poem written by astropoet Stuart Atkinson (used here by permission).

Rosetta’s Last Letter Home

By Stuart Atkinson

And so, my final day dawns.
Just a few grains are left to drain through
The hourglass of my life.
The Comet is a hole in the sky.
Rolling, turning, a black void churning
Silently beneath me.
Down there, waiting for me, Philae sleeps,
Its bed a cold cave floor,
A quilt of sparkling hoarfrost
Pulled over its head…

I have so little time left;
I sense Death flying behind me,
I feel his breath on my back as I look down
At Ma’at, its pits as black as tar,
A skulls’s empty eye sockets staring back
At me, daring me to leave the safety
Of this dusty sky and fly down to join them,
Never to spread my wings again; never
To soar over The Comet’s tortured pinnacles and peaks,
Or play hide and seek in its jets and plumes…

I don’t want to go.
I don’t want to be buried beneath that filthy snow.
This is wrong! I want to fly on!
There is so much more for me to see,
So much more to do –
But the end is coming soon.
All I ask of you is this: don’t let me crash.
Help me land softly, kissing the ground,
Coming to rest with barely a sound
Like a leaf falling from a tree.
Don’t let me die cartwheeling across the plain,
Wings snapping, cameras shattering,
Pieces of me scattering like shrapnel
Across the ice. Let me end my mayfly life
In peace, whole, not as debris rolling uncontrollably
Into Deir el-Medina…

It’s time to go, I know.
Only hours remain until I join Philae
And my great adventure ends
So I’ll send this and say goodbye.
If I dream, I’ll dream of Earth
Turning beneath me, bathing me in
Fifty shades of blue…
In years to come I hope you’ll think of me
And smile, remembering how, for just a while,
We explored a wonderland of ice and dust
Together, hand in hand.

(c) Stuart Atkinson 2016

Rosetta Wows With Amazing Closeups of Comet 67P Before Final ‘Crunchdown’

Landscape on Comet 67P taken from just 10 miles (16 km) up late Thursday evening during Rosetta's free fall . The image measures 2,014 feet (614 meters) across or just under a half-mile. At typical walking speed, you could walk from one end to the other in 10 minutes. Credit: ESA/Rosetta
Craggy hills meet dust-covered plains in this landscape on Comet 67P taken from 10 miles (16 km) up late Thursday evening during Rosetta’s free fall . The image measures 2,014 feet (614 meters) across or just under a half-mile. At typical walking speed, you could walk from one side to the other in 10 minutes. This and all the photos below are copyright ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Rosetta fell silent moments after 6:19 a.m. Eastern Time (12:19 UT) this morning, when it gently crashed into 67P/C-G 446 million miles (718 million km) from Earth. As the probe descended to the comet’s bouldery surface of the comet in free fall, it snapped a series of ever-more-detailed photographs while gathering the last bits data on the density and composition of cometary gases, surface temperature and gravity field before the final curtain was drawn.

Let’s take the trip down, shall we?

Rosetta's last navigation camera image was taken just after the collision maneuver sequence Thursday evening (CDT) when the probe was 9.56 miles (15.4 km) above the comet's surface. Credit: ESA/Rosetta
Rosetta’s last navigation camera image was taken just after the collision maneuver sequence Thursday evening (CDT) when the probe was 9.56 miles (15.4 km) above the comet’s surface. As in the photo above, much of the landscape is coated in a thick layer of dust that smoothes the comet’s contours.
As Rosetta continues its descent onto the Ma'at region on the small lobe of Comet 67P/Churyumov-Gerasimenko, the OSIRIS narrow-angle camera captured this image at 08:18 GMT from an altitude of about 5.8 km. The image shows dust-covered terrains, exposed walls and a few boulders on Ma'at, not far from the target impact region (not visible in this view - located below the lower edge).Copyright ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
As Rosetta continued its descent onto the Ma’at region on the small lobe of Comet 67P/Churyumov-Gerasimenko, the OSIRIS narrow-angle camera captured this photo from 3.6 miles (5.8 km) up. We see dust-covered terrains, exposed walls and a few boulders on Ma’at, not far from the target impact region, which is located just below the lower edge. The image measures 738 feet (225 meters) across.
Comet from 5.7 km. Rosetta’s OSIRIS narrow-angle camera captured this image of Comet 67P/Churyumov-Gerasimenko at 08:21 GMT during the spacecraft’s final descent on September 30, 2016. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Just a little bit lower now. This photo showing dramatic shadows was taken from 3.5 miles (5.7 km) above the surface of the comet at 4:21 a.m. EDT Friday morning September 30.
It looks like the probe's headed for the abyss! This photo was made at 6:14 a.m. just minutes before impact from 3/4 mile (1.2 km) high. The scene measures just 33 meters across.
Headed for the abyss? This photo was made at 6:14 a.m. from 3/4 mile (1.2 km) high just a few minutes before impact. The scene measures just 108 feet (33 meters) wide.
This is Rosetta's last image of Comet 67P/Churyumov-Gerasimenko, taken shortly before impact, an estimated 51 m above the surface.
This is Rosetta’s final image of Comet 67P/Churyumov-Gerasimenko, taken shortly before impact, an estimated 66 feet (~20 meters) above the surface. The view is similar to looking down from atop a three-story building. Side to side, the photo depicts an area only 7.8 feet (2.4 meters) across. The image is soft because Rosetta’s cameras weren’t designed to photograph the comet from this close.
Sad to see its signal fade. Going... going... gone! A sequence of screenshots showing the signal from Rosetta seen at ESA's ESOC mission control centre via NASA's 70m tracking station at Madrid during comet landing on 30 September 2016. The peak of the spectrum analyser is strong at 12:19 CEST, and a few moments later, it's gone. Credit: ESA
Sad to see its signal fade. A sequence of screenshots taken at ESA’s ESOC mission control show the signal from Rosetta fading moments before impact. The peak of the spectrum analyser is strong at 6:19 EDT, and a few moments later, it’s gone. At impact, Rosetta’s was shut down and no further communication will or can be made with the spacecraft. It will continue to rest on the comet for well-nigh eternity until 67P vaporizes and crumbles apart. Credit: ESA

Bye, Bye Rosetta — We’ll Miss You!

Activity increases substantially at Comet 67P/Churyumov-Gerasimenko between Jan. 31 and March 25, 2015, when this series of pictures was taken by the Rosetta spacecraft. Credit: NAVCAM_CC-BY_SA-IGO-3.0
This montage of photos of Comet 67P/Churyumov-Gerasimenko was taken by ESA’s Rosetta spacecraft between Jan. 31 and March 25, 2015 and shows increasing activity as the comet approached perihelion. Credit: NAVCAM /CC-BY-SA-IGO-3.0

Rosetta awoke from a decade of deep-space hibernation in January 2014 and immediately got to work photographing, measuring and sampling comet 67P/C-G. On September 30 it will sleep again but this time for eternity. Mission controllers will direct the probe to impact the comet’s dusty-icy nucleus within 20 minutes of 10:40 Greenwich Time (6:40 a.m. EDT) that Friday morning. The high-resolution OSIRIS camera will be snapping pictures on the way down, but once impact occurs, it’s game over, lights out. Rosetta will power down and go silent.

A simplified overview of Rosetta’s last week of manoeuvres at Comet 67P/Churyumov–Gerasimenko (comet rotation is not considered). After 24 September the spacecraft will leave the flyover orbits and transfer towards an initial point of a 16 x 23 km orbit that will be used to prepare for the final descent. The collision course manoeuvre will take place in the evening of 29 September, initiating the descent from an altitude of about 20 km. The impact is expected to occur at 10:40 GMT (±20 minutes) at the comet, which taking into account the 40 minute signal travel time between Rosetta and Earth on 30 September, means the confirmation would be expected at mission control at 11:20 GMT / 13:20 CEST (±20 minutes).
A simplified overview of Rosetta’s last week of maneuvers at Comet 67P/Churyumov–Gerasimenko. Starting today (Sept. 24) the spacecraft will leave the flyover orbits and transfer towards a 16 x 23 km orbit that will be used to prepare for the final descent. The collision course maneuver will take place in the evening Sept. 29 with impact expected to occur at 10:40 GMT (6:40 a.m. EDT), which taking into account the 40 minute signal travel time between Rosetta and Earth on Sept. 30, means the confirmation would be expected at mission control at 11:20 GMT (7:20 a.m. EDT). Copyright: ESA

Nearly three years have passed since Rosetta opened its eyes on 67P, this curious, bi-lobed rubber duck of a comet just 2.5 miles (4 km) across with landscapes ranging from dust dunes to craggy peaks to enigmatic ‘goosebumps’. The mission was the first to orbit a comet and dispatch a probe, Philae, to its surface. I think it’s safe to say we learned more about what makes comets tick during Rosetta’s sojourn than in any previous mission.

So why end it? One of the big reasons is power. As Rosetta races farther and farther from the Sun, less sunlight falls on its pair of 16-meter-long solar arrays. At mid-month, the probe was over 348 million miles (560 million km) from the Sun and 433 million miles (697 million km) from Earth or nearly as far as Jupiter. With Sun-to-Rosetta mileage increasing nearly 620,000 miles (1 million km) a day, weakening sunlight can’t provide the power needed to keep the instruments running.


Rosetta’s last orbits around the comet

Rosetta’s also showing signs of age after having been in the harsh environment of interplanetary space for more than 12 years, two of them next door to a dust-spitting comet. Both factors contributed to the decision to end the mission rather than put the probe back into an even longer hibernation until the comet’s next perihelion many years away.

Since August 9, Rosetta has been swinging past the comet in a series of ever-tightening loops, providing excellent opportunities for close-up science observations. On September 5, Rosetta swooped within 1.2 miles (1.9 km) of 67P/C-G’s surface. It was hoped the spacecraft would descend as low as a kilometer during one of the later orbits as scientists worked to glean as much as possible before the show ends.

Rosetta will land somewhere within this planned impact ellipse in the Ma'at region on the comet's smaller lobe. Copyright: ESA
Rosetta is targeted to land at the site within this planned impact ellipse in the Ma’at region on the comet’s smaller lobe. See below for a closer view. Credit: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0

The final of 15 close flyovers will be completed today (Sept. 24) after which Rosetta will be maneuvered from its current elliptical orbit onto a trajectory that will eventually take it down to the comet’s surface on Sept. 30.

The beginning of the end unfolds on the evening of the 29th when Rosetta spends 14 hours free-falling slowly towards the comet from an altitude of 12.4 miles (20 km) — about 4 miles higher than a typical commercial jet — all the while collecting measurements and photos that will be returned to Earth before impact. The last eye-popping images will be taken from a distance of just tens to a hundred meters away.

The landing will be a soft one, with the spacecraft touching down at walking speed. Like Philae before it, it will probably bounce around before settling into place. Mission control expects parts of the probe to break upon impact.

Taking into account the additional 40 minute signal travel time between Rosetta and Earth on the 30th, confirmation of impact is expected at ESA’s mission control in Darmstadt, Germany, within 20 minutes of 11:20 GMT (7:20 a.m. EDT). The times will be updated as the trajectory is refined. You can watch live coverage of Rosetta’s final hours on ESA TV .


ESAHangout: Preparing for Rosetta’s grand finale

“It’s hard to believe that Rosetta’s incredible 12.5 year odyssey is almost over, and we’re planning the final set of science operations, but we are certainly looking forward to focusing on analyzing the reams of data for many decades to come,” said Matt Taylor, ESA’s Rosetta project scientist.

The spacecraft will aim at a point just right of the image centre, next to Deir el-Medina, the large pit located slightly below and to the right of centre in this view. Credit: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0
The spacecraft landing site is shown in red and located next to Deir el-Medina, a large pit (arrowed). Credit: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0

Plans call for the spacecraft to impact the comet somewhere within an ellipse about 1,300 x 2,000 feet (600 x 400 meters) long on 67P’s smaller lobe in the region known as Ma’at. It’s home to several active pits more than 328 feet (100 meters) in diameter and 160-200 feet (50-60 meters) deep, where a number of the comet’s dust jets originate. The walls of the pits are lined with fascinating meter-sized lumpy structures called ‘goosebumps’, which scientists believe could be early ‘cometesimals’, the icy snowballs that stuck together to create the comet in the early days of our Solar System’s formation.

Close-up of a curious surface texture nicknamed ‘goosebumps’. The characteristic scale of all the bumps seen on Comet 67P/Churyumov–Gerasimenko by the OSIRIS narrow-angle camera is approximately 3 m, extending over regions greater than 100 m. They are seen on very steep slopes and on exposed cliff faces, but their formation mechanism is yet to be explained. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Close-up of a curious surface texture nicknamed ‘goosebumps’. The bumps are about 9 feet (3 meters) across and seen on very steep slopes and exposed cliff faces. They may represent the original balls of icy dust that glommed together to form comets 4.5 billion years ago. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

During free-fall, the spacecraft will target a point adjacent to a 425-foot (130 m) wide, well-defined pit that the mission team has informally named Deir el-Medina, after a structure with a similar appearance in an ancient Egyptian town of the same name. High resolution images should give us a spectacular view of these enigmatic bumps.

While we hate to see Rosetta’s mission end, it’s been a blast going for a 2-year-plus comet ride-along.

Weekly Space Hangout – Sept 23, 2016: Dr. Frank Timmes and Online Astronomy Education

Host: Fraser Cain (@fcain)

Special Guests:
Dr. Frank Timmes is an astrophysicist at Arizona State University and will be discussing online astronomy education and the Global Freshman Academy. His interests include the universe’s evolving composition and its implications for life in the universe. Dr. Timmes’ current area of research is nuclear astrophysics and the creation of the periodic table.

Guests:

Morgan Rehnberg (MorganRehnberg.com / @MorganRehnberg)
Dave Dickinson (www.astroguyz.com / @astroguyz)
Kimberly Cartier ( KimberlyCartier.org / @AstroKimCartier )
Nicole Gugliucci (cosmoquest.org / @noisyastronomer)

Their stories this week:

New bill targets serial harasses

Tiangong-1 to crash next year

The Final Days of Rosetta

Microlensing circumbinary planet detected

Repeat of Voyager’s “impossible” cloud

We are now using a tool called Trello to submit and vote on stories we would like to see covered each week, and then Fraser will be selecting the stories from there. Here is the link to the Trello WSH page (http://bit.ly/WSHVote), which you can see without logging in. If you’d like to vote, just create a login and help us decide what to cover!

We record the Weekly Space Hangout every Friday at 12:00 pm Pacific / 3:00 pm Eastern. You can watch us live on Universe Today, or the Universe Today YouTube page.

There It Is! Philae Lander Found

The search is over, and looking at these images, no wonder it was so hard to find the little Philae lander!

The high-resolution camera on board the Rosetta spacecraft has finally spotted Philae “wedged into a dark crack on Comet 67P/Churyumov-Gerasimenko,” the ESA team said. They also said that now, seeing the lander’s orientation, it’s clear why establishing communications was so difficult following its landing on November 12, 2014.

Close-up of the Philae lander.  Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Close-up of the Philae lander. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Rosetta, orbiting the comet and getting ready for its own demise/touchdown on 67P, focused its OSIRIS narrow-angle camera towards a few candidate sites on September 2, 2016 as the orbiter came just 2.7 km of the comet’s surface. Clearly visible in the zoomed in versions are the main body of the lander, along with two of its three legs.

“With only a month left of the Rosetta mission, we are so happy to have finally imaged Philae, and to see it in such amazing detail,” says Cecilia Tubiana of the OSIRIS camera team, the first person to see the images when they were downlinked from Rosetta on September 4.

Tubiana told Universe Today via email that Philae wasn’t too hard to find in the images. “Philae was in hiding in shadow, and as soon as we stretched the brightness to ‘see’ into the shadow, Philae was there!”

She added that nothing else about Philae’s condition has been revealed from the images so far.

The Philae lander was last seen after it first touched down at a region called Agilkia on the odd-shaped, two-lobed comet 67P. During its dramatic touchdown, the lander flew, landed, bounced and then repeated that process for more than two hours across the surface, with three or maybe four touchdowns. The harpoons that were to anchor Philae to the surface failed to fire, and scientists estimated the lander may have bounced as high as 3.2 kilometers (2 miles) before becoming wedged in the shadows of a cliff on the comet. After three days, Philae’s primary battery ran out of power and the lander went into hibernation, only to wake up again and communicate briefly with Rosetta in June and July 2015 as the comet came closer to the Sun and more power was available.

But after more than a year of silence, the Rosetta team announced in mid-August 2016 that they would no longer attempt communications with Philae.

Philae’s final location had been plotted but until yesterday, never actually seen by Rosetta’s cameras. Radio ranging data was used to narrow down the search to an area spanning a few tens of meters, and a number of potential candidate objects were identified in relatively low-resolution images taken from larger distances.

Philae close-up, labelled. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA.
Philae close-up, labelled. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA.

Compare some of the features of the cliff in the image above to this image taken by Philae of its surroundings:

The Philae lander captured a picture of a nearby cliff, nicknamed “Perihelion Cliff”, on the nucleus of Comet 67P/Churyumov-Gerasimenko. Credit: ESA/Rosetta/Philae/CIVA.
The Philae lander captured a picture of a nearby cliff, nicknamed “Perihelion Cliff”, on the nucleus of Comet 67P/Churyumov-Gerasimenko. Credit: ESA/Rosetta/Philae/CIVA.

“After months of work, with the focus and the evidence pointing more and more to this lander candidate, I’m very excited and thrilled that we finally have this all-important picture of Philae sitting in Abydos,” said ESA’s Laurence O’Rourke, who has been coordinating the search efforts over the last months at ESA, with the OSIRIS and SONC/CNES teams.

At 2.7 km, the resolution of the OSIRIS narrow-angle camera is about 5 cm/pixel, which is sufficient to reveal features of Philae’s 1 m-sized body and its legs.

“This wonderful news means that we now have the missing ‘ground-truth’ information needed to put Philae’s three days of science into proper context, now that we know where that ground actually is!” says Matt Taylor, ESA’s Rosetta project scientist.

An OSIRIS narrow-angle camera image taken on 2 September 2016 from a distance of 2.7 km in which Philae was definitively identified. The image has been processed to adjust the dynamic range in order to see Philae while maintaining the details of the comet's surface. Philae is located at the far right of the image, just above center. The image scale is about 5 cm/pixel. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA.
An OSIRIS narrow-angle camera image taken on 2 September 2016 from a distance of 2.7 km in which Philae was definitively identified. The image has been processed to adjust the dynamic range in order to see Philae while maintaining the details of the comet’s surface. Philae is located at the far right of the image, just above center. The image scale is about 5 cm/pixel. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA.

The discovery comes less than a month before Rosetta descends to the comet’s surface. On September 30, the orbiter will be sent on a final one-way mission to investigate the comet from close up, including the open pits in a region called Ma’at, where it is hoped that critical observations will help to reveal secrets of the body’s interior structure.

“Now that the lander search is finished we feel ready for Rosetta’s landing, and look forward to capturing even closer images of Rosetta’s touchdown site,” adds Holger Sierks, principal investigator of the OSIRIS camera.

The Rosetta team said they would be providing more details about the search as well as more images in the near future.

Source: ESA

Rosetta’s Philae Lander in Permanent Sleep

NAVCAM image of comet 67P/Churyumov-Gerasimenko acquired on Nov. 22, 2015.
NAVCAM image of comet 67P/Churyumov-Gerasimenko acquired on Nov. 22, 2015. Credit: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0.

ESA’s Philae lander, the first spacecraft to successfully soft-land on the surface of a comet and former piggyback partner to Rosetta, has not been in communication since July of 2015 and, with 67P now six months past perihelion and heading deeper out into the Solar System, it’s not likely it will ever be heard from again.

Continue reading “Rosetta’s Philae Lander in Permanent Sleep”

Weekly Space Hangout – Feb. 5, 2016: Dr. Or Graur

Host: Fraser Cain (@fcain)

Special Guest: Dr. Or Graur, Research Associate at the Center for Cosmology and Particle Physics at New York University; Researches what type of star leads to a thermonuclear, or “Type Ia,” supernova.

Guests:
Carolyn Collins Petersen (thespacewriter.com / space.about.com / @spacewriter )
Morgan Rehnberg (cosmicchatter.org / @MorganRehnberg )
Jolene Creighton (fromquarkstoquasars.com / @futurism)
Alessondra Springmann (@sondy)

Continue reading “Weekly Space Hangout – Feb. 5, 2016: Dr. Or Graur”

How to Find Rosetta’s Comet In Your Telescope

How would you like to see one of the most famous comets with your own eyes? Comet 67P/Churyumov-Gerasimenko plies the morning sky, a little blot of fuzzy light toting an amazing visitor along for the ride — the Rosetta spacecraft. When you look at the coma and realize a human-made machine is buzzing around inside, it seems unbelievable. 

Comet 67P/Churyumov-Gerasimenko plows through a rich star field in Gemini on the morning of August 19, 2015. Photos show a short, faint tail to the west not visible to the eye in most amateur telescopes. Credit: Efrain Morales
Comet 67P/Churyumov-Gerasimenko plows through a rich star field in Gemini on the morning of August 20, 2015. Photos show a short, faint tail to the west not visible to the eye in most amateur telescopes. Credit: Efrain Morales

If you have a 10-inch or larger telescope, or you’re an experienced amateur with an 8-inch and pristine skies, 67P is within your grasp. The comet glows right around magnitude +12, about as bright as it will get this apparition. Periodic comets generally appear brightest around and shortly after perihelion or closest approach to the Sun, which for 67P/C-G occurred back on August 13.

The surface of Comet 67P/C-G is extensively fractured likely related to the intense freeze-thaw cycle that occurs during the heat of perihelion vs. the chill experienced in the outer part of its orbit. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
The surface of Comet 67P/C-G is extensively fractured due to loss of volatile ices, the expansion and contraction of the comet from solar heating and bitter cold and possibly even tectonic forces. The smaller polygonal shapes outlined by fractures in the lower right photo are just 6-16 feet (2-5 meters) across. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

You’ll be looking for a small, 1-arc-minute-diameter, compact, circular patch of nebulous light shortly before dawn when it’s highest in the east. Rosetta’s Comet will spend the remainder of August slicing across Gemini the Twins north of an nearly parallel to the ecliptic. I spotted 67P/C-G for the first time this go-round about a week ago in my 15-inch (37 cm) reflector. While it appears like a typical faint comet, thanks to Rosetta, we know this particular rough and tumble mountain of ice better than any previous comet. Photographs show rugged cliffs, numerous cracks due to the expansion and contraction of ice, blowholes that serve as sources for jets and smooth plains blanketed in fallen dust.

Geysers of dust and gas shooting off the comet's nucleus are called jets. The material they deliver outside the nucleus builds the comet's coma. Credit: ESA/Rostta/NAVCAM
Geysers of dust and gas shooting off the comet’s nucleus are called jets. The material they deliver outside the nucleus builds the comet’s coma. Credit: ESA/Rostta/NAVCAM

The jets are geyser-like sprays of dust and gas that loft grit and rocks from the comet’s interior and surface into space to create a coma or temporary atmosphere. This is what you’ll see in your telescope. And if you’re patient, you’ll even be able to catch this glowing tadpole on the move. I was surprised at its speed. After just 20 minutes, thanks to numerous field stars that acted as references, I could easily spot the comet’s eastward movement using a magnification of 245x.

Facing east around 4 a.m. local time in late August, you'll see the winter constellations Gemini and Orion. 67P/C-G's path is shown through
Facing east around 4 a.m. local time in late August, you’ll see the winter constellations Gemini and Orion. 67P/C-G’s path is shown through early September. Brighter stars near the path are labeled. Time shown is 4 a.m. CDT. Use this map to get oriented and then switch to the one below for telescope use. Source: Chris Marriott’s SkyMap

Tomorrow morning, 67P/C-G passes very close to the magnitude +5 star Omega Geminorum. While this will make it easy to locate, the glare may swamp the comet. Set your alarm for an hour before dawn’s start to allow time to set up a telescope, dark-adapt your eyes and track down the field where the comet will be that morning using low magnification.

Once you’ve centered 67P/C-G’s position, increase the power to around 100x-150x and use averted vision to look for a soft, fuzzy patch of light. If you see nothing, take it to the next level (around 200-250x) and carefully search the area. The higher the magnification, the darker the field of view and easier it will be to spot it.

Detailed map showing the comet's path through central Gemini daily August 21-28, 2015 around 4 a.m. CDT. Brighter stars are marked with Greek letters and numbers. "48" = 48 Geminorum. Source: Chris Marriott's SkyMap
Detailed map showing the comet’s path through central Gemini daily August 21-28, 2015 around 4 a.m. CDT. Brighter stars are marked with Greek letters and numbers. “57”= 57 Geminorum. North is up, east to the left and stars to magnitude +13.5. Click for a larger version you can print out. Source: Chris Marriott’s SkyMap

Besides being relatively faint, the comet doesn’t get very high in the east before the onset of twilight. Low altitude means the atmosphere absorbs a share of the comet’s light, making it appear even fainter. Not that I want to dissuade you from looking! There’s nothing like seeing real 67P photons not to mention the adventure and sense of accomplishment that come from finding the object on your own.

As we advance into late summer and early fall, 67P/C-G will appear higher up but also be fading. Now through about August 27 and again from September 10-24 will be your best viewing times. That’s when the Moon’s absent from the sky.

Given the comet’s current distance from Earth of 165 million miles and apparent visual size of just shy of 1 arc minute, the coma measures very approximately 30,000 miles across. Rosetta orbits the comet’s 2.5-mile-long icy nucleus at a distance of about 115 miles (186 km), meaning it’s snug up against the nuclear center from our point of view on the ground.

If you do find and follow 67P/C-G, consider sharing your observations with the Pro-Amateur Collaborative Astronomy (PACA) campaign to help increase our knowledge of its behavior. Interested? Sign up HERE.

More Evidence That Comets May Have Brought Life to Earth

The idea of panspermia — that life on Earth originated from comets or asteroids bombarding our planet — is not new. But new research may have given the theory a boost. Scientists from Japan say their experiments show that early comet impacts could have caused amino acids to change into peptides, becoming the first building blocks of life. Not only would this help explain the genesis of life on Earth, but it could also have implications for life on other worlds.

Dr. Haruna Sugahara, from the Japan Agency for Marine-Earth Science and Technology in Yokahama, and Dr. Koichi Mimura, from Nagoya University said they conducted “shock experiments on frozen mixtures of amino acid, water ice and silicate (forsterite) at cryogenic condition (77 K),” according to their paper. “In the experiments, the frozen amino acid mixture was sealed into a capsule … a vertical propellant gun was used to [simulate] impact shock.”

They analyzed the post-impact mixture with gas chromatography, and found that some of the amino acids had joined into short peptides of up to 3 units long (tripeptides).

Based on the experimental data, the researchers were able to estimate that the amount of peptides produced would be around the same as had been thought to be produced by normal terrestrial processes (such as lighting storms or hydration and dehydration cycles).

Artists concept of the stardust spacecraft flying throug the gas and dust from comet Wild 2. Credit: NASA/JPL
Artists concept of the stardust spacecraft flying throug the gas and dust from comet Wild 2. Credit: NASA/JPL
“This finding indicates that comet impacts almost certainly played an important role in delivering the seeds of life to the early Earth,” said Sugahara. “It also opens the likelihood that we will have seen similar chemical evolution in other extraterrestrial bodies, starting with cometary-derived peptides.”

The earliest known fossils on Earth are from about 3.5 billion years ago and there is evidence that biological activity took place even earlier. But there’s evidence that early Earth had little water and carbon-based molecules on the Earth’s surface, so how could these building blocks of life delivered to the Earth’s surface so quickly? This was also about the time of the Late Heavy Bombardment, and so the obvious answer could be the collision of comets and asteroids with the Earth, since these objects contain abundant supplies of both water and carbon-based molecules.

A view of NASA's Deep Impact probe colliding with comet Tempel 1, captured by the Deep Impact flyby spacecraft's high-resolution instrument.
A view of NASA’s Deep Impact probe colliding with comet Tempel 1, captured by the Deep Impact flyby spacecraft’s high-resolution instrument.

Space missions to comets are helping to confirm this possibility. The 2004 Stardust mission found the amino acid when it collected particles from Comet Wild 2. When NASA’s Deep Impact spacecraft crashed into Comet Tempel 1 in 2005, it discovered a mixture of organic and clay particles inside the comet. One theory about the origins of life is that clay particles act as a catalyst, allowing simple organic molecules to get arranged into more and more complex structures.

The news from the current Rosetta mission to comet 67P/Churyumov-Gerasimenko also indicates that comets are a rich source of materials, and more discoveries are likely to be forthcoming from that mission.

Jets of gas and dust are blasting from the active neck of comet 67P/Churyumov-Gerasimenko in this photo mosaic assembled from four images taken on 26 September 2014 by the European Space Agency’s Rosetta spacecraft at a distance of 26.3 kilometers (16 miles) from the center of the comet. Credit: ESA/Rosetta/NAVCAM/Marco Di Lorenzo/Ken Kremer/kenkremer.com
Jets of gas and dust are blasting from the active neck of comet 67P/Churyumov-Gerasimenko in this photo mosaic assembled from four images taken on 26 September 2014 by the European Space Agency’s Rosetta spacecraft at a distance of 26.3 kilometers (16 miles) from the center of the comet. Credit: ESA/Rosetta/NAVCAM/Marco Di Lorenzo/Ken Kremer/kenkremer.com

“Two key parts to this story are how complex molecules are initially generated on comets and then how they survive/evolve when the comet hits a planet like the Earth,” said Professor Mark Burchell from the University of Kent in the UK, commenting on the new research from Japan. “Both of these steps can involve shocks which deliver energy to the icy body… building on earlier work, Dr. Sugahara and Dr. Mimura have shown how amino acids on icy bodies can be turned into short peptide sequences, another key step along the path to life.”

“Comet impacts are normally associated with mass extinction on Earth, but this works shows that they probably helped kick-start the whole process of life in the first place,” said Sugahara. “The production of short peptides is the key step in the chemical evolution of complex molecules. Once the process is kick-started, then much less energy is needed to make longer chain peptides in a terrestrial, aquatic environment.”

The scientists also indicated that similar “kickstarting” could have happened in other places in our Solar System, such as on the icy moons Europa and Enceladus, as they likely underwent a similar comet bombardment.

Sugahara and Mimura presented their findings at the Goldschmidt geochemistry conference in Prague, going on this week.