Cassini gives us clues about the Great Red Spot’s color.
New research on the Great Red Spot of Jupiter based on Cassini’s flyby nearly 14 years ago (Dec 2000) suggests the red color is from the “sunburn” of particles and the variable color comes from cloud altitudes.
The ruddy color of Jupiter’s Great Red Spot is likely a product of simple chemicals being broken apart by sunlight in the planet’s upper atmosphere, according to a new analysis of data from NASA’s Cassini mission. The results contradict the other leading theory for the origin of the spot’s striking color — that the reddish chemicals come from beneath Jupiter’s clouds.
The results are being presented this week by Kevin Baines, a Cassini team scientist based at NASA’s Jet Propulsion Laboratory, Pasadena, California, at the American Astronomical Society’s Division for Planetary Science Meeting in Tucson, Arizona.
Baines and JPL colleagues Bob Carlson and Tom Momary arrived at their conclusions using a combination of data from Cassini’s December 2000 Jupiter flyby and laboratory experiments.
In the lab, the researchers blasted ammonia and acetylene gases — chemicals known to exist on Jupiter — with ultraviolet light, to simulate the sun’s effects on these materials at the extreme heights of clouds in the Great Red Spot. This produced a reddish material, which the team compared to the Great Red Spot as observed by Cassini’s Visible and Infrared Mapping Spectrometer (VIMS). They found that the light-scattering properties of their red concoction nicely matched a model of the Great Red Spot in which the red-colored material is confined to the uppermost reaches of the giant cyclone-like feature.
“Our models suggest most of the Great Red Spot is actually pretty bland in color, beneath the upper cloud layer of reddish material,” said Baines. “Under the reddish ‘sunburn’ the clouds are probably whitish or grayish.” A coloring agent confined to the top of the clouds would be inconsistent with the competing theory, which posits that the spot’s red color is due to upwelling chemicals formed deep beneath the visible cloud layers, he said. If red material were being transported from below, it should be present at other altitudes as well, which would make the red spot redder still.
Neptune and Triton from the New Horizons spacecraft. Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
A look at Neptune and one of its moons Triton from New Horizons spacecraft on 10 July 2014. When the image was taken, New Horizons had not crossed the orbit of Neptune. At the orbit crossing New Horizons was actually closer to Pluto than Neptune.
See the non-annotated version here.
Coming up very soon, on 06 December 2015 New Horizons will exit sleep mode for the last time. The spacecraft has periodically gone in and out of sleep mode so there shouldn’t be any surprises. From then on the spacecraft will be fully awake and very shortly after will start taking science data. We should get some tantalizing views of the Plutonian system from the same camera that took the one above: New Horizons telescopic Long-Range Reconnaissance Imager (LORRI).
ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
The Philae lander might be hibernating and as far as I know the whereabouts of the lander isn’t known for sure, we do know about the journey.
The mosaic above is a series of images taken by the OSIRIS narrow angle camera aboard Rosetta over about a half hour. At the time Rosetta was only 15.5 km / 28 miles from the surface of the comet.
The mosaic captures Philae starting at the lower left and follows it upward as labeled on the image.
Like I said in the beginning, mission managers don’t know where Philae is but they will find it. It is known the lander was moving east with a rate of travel about a half a meter per second, that’s really slow for a spacecraft. Think about a leisurely walk, now go slower by better than half, on average, you would still probably beat Philae in a race.
Will Philae be found? I would say yes most likely it will. Data returned from the mission including the CONSERT ranging data, OSIRIS and navcam images on Rosetta along with Philae’s ROLIS and CIVA cameras should reveal the resting spot. When the lander is found mission managers will have a much better idea about the future of the mission.
Aside from the amazing Rosetta mission there is quite a lot of other things going on, so here’s a video to catch up a little with NASA.
Decline in battery power aboard Philae. Credit: ESA via Twitter
The Philae lander is now in an “idle mode” in which most of the systems on board are shut down, including communications.
Before going to sleep, Philae was able to send all of the science data collected so far and completed its main mission in the 57 hours on the comet surface.
Stephan Ulamec, Lander Manager said “This machine performed magnificently under tough conditions, and we can be fully proud of the incredible scientific success Philae has delivered.”
Contact with Philae was lost at 00:36 UT (20:36 EST for the US), according to Rosetta Blog this was about the time of a scheduled loss of signal anyway as Rosetta which was acting as a repeater orbited out of sight of Philae.
Rosetta mission control did try to rotate the lander as was reported and with that effort there was a possibility of communications at 10:00 UTC (05:00 EST) this morning (15 Nov) so Rosetta was listening but no signal came.
As Comet 67P/Churyumov-Gerasimenko gets closer to the Sun there is a possibility enough sunlight will eventually revive the batteries enough to get Philae back on-line. Still I have to wonder if the deep discharge state of the batteries will preclude that given the time and cold environment – time will tell.
A news briefing from 14 November with some of the early details on the Rosetta mission and Philae landing.
The real question is now will Philae ever talk again? The mission managers were going to attempt to get more of the solar panels into sunlight to charge the now dead battery. For now Philae is considered to be in hibernation.
Philae is right at home. Credits: ESA/Rosetta/Philae/CIVA
WOW! This is just simply amazing.
This is a two image mosaic of Philae on the surface of the Comet 67P/Churyumov-Gerasimenko. Click the image and just marvel at the view of both Philae and the surface features.
You can get an even larger version at Rosetta blog’s Welcome to a Comet!
Philae is pretty close to a cliff that will shadow the solar panels for much of a day and this will limit how much Philae will be able to do at least in the short term. I’m pretty sure ESA is studying how to squeeze the most out of what they have you can be sure of that.
ESA is live streaming the media briefings, you can find out when by going to Rosetta Blog or you can check the Live Stream page.
Don’t forget about Twitter, I am on the run a lot the past couple days and it has been great for keeping up you can get all the images and briefings there too.
ROLIS descent image of Comet 67P/C-G. Credits: ESA/Rosetta/Philae/ROLIS/DLR
As the Philae lander approached comet 67P/G-C it used the ROLIS instrument to take this image at 14:38:41 UT from just 3 km / 1.9 miles above the surface.
The ROLIS instrument looks downward during descent and gets close up views after landing so texture and microsturcture of surface materials.
Yes, that is part of the lander you see in the upper right.
ROLIS (ROsetta Lander Imaging System) is a descent and close-up camera on the Philae Lander. It has been developed by the DLR Institute of Planetary Research, Berlin.
I had to include the image below, I think it’s just excellent. We are looking at the Philae lander shortly after being released from the mother ship (Rosetta) after a 10 year trip together on this totally amazing mission.
Good luck Philae. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
No word yet on what is going on with the harpoons (anchors), but ESA did mention “Maybe today we didn’t just land once…we even landed twice!”
There will be plenty more images here, but check out the Rosetta Blog.
ESA Rosetta Mission on Twitter
Congratulations ESA !
I bet the smiles are abundant and they should be.
GOOD LUCK! I can hardly believe the day has finally come – it’s been a long time!
Update: Landing confirmed. Harpoons did not fire, investigation in progress. The one way radio travel time is a bit over 28 minutes – each way.
ESA is reporting all is well with Philae is in good shape despite the harpoons.
If you see no video above it is because ESA isn’t broadcasting at the time.
Check out the Rosetta Blog and for last second updates.
Philae timeline. Click for a more readable version. Credit: ESA
The big day is almost here. What will happen once Philae lands on Comet 67P/Churyumov–Gerasimenko?
This from ESA:
A timeline of the science operations that Rosetta’s lander Philae will perform during the first 2.5 days on the surface of Comet 67P/Churyumov–Gerasimenko.
It does not include the experiments conducted during the seven-hour descent or immediately upon touchdown and in the 40 minutes after as the separation, descent and landing operations and experiments conclude (see this graphic for a summary of those activities).