Tag: comets
New images of Comet ISON.
The lingering echo of Comet Shoemaker-Levy in the atmosphere of Jupiter.
The lingering echo of Comet Shoemaker-Levy in the atmosphere of Jupiter.
The Herschel observations, together with heat maps provided by NASA’s Infrared Telescope Facility on Mauna Kea, showed the researchers that the Jovian stratosphere was 20° to 30°F (10° to 15°C) warmer than it would be if completely dry. One question is whether the stratospheric warming results from the gentle, continuous infall of interplanetary dust particles, which would be warmed by sunlight as they linger high up. Cavalié and his colleagues believe IDPs create some of the infrared emission but cannot explain it all. Further, a continuously supplied source would migrate to lower depths, yet most of the emission is too high up, at pressures less than 2 millibars. And while the amount of water is roughly constant across the southern hemisphere, the emission gradually weakens northward until it’s less than half as strong. It’s not simply that Jupiter’s bottom half is hotter — there’s just more water down there. As the researchers note, “At least 95% of the observed water comes from the SL9 comet and subsequent (photo)-chemistry in Jupiter’s stratosphere according to our models, as of today.
Taken together, they conclude, these observations offer “clear evidence that a recent comet … is the principal source of water in Jupiter. What we observe today is a remnant of the oxygen delivery by the comet at 44°S in July 1994.”
The lingering echo of Comet Shoemaker-Levy in the atmosphere of Jupiter.
The Herschel observations, together with heat maps provided by NASA’s Infrared Telescope Facility on Mauna Kea, showed the researchers that the Jovian stratosphere was 20° to 30°F (10° to 15°C) warmer than it would be if completely dry. One question is whether the stratospheric warming results from the gentle, continuous infall of interplanetary dust particles, which would be warmed by sunlight as they linger high up. Cavalié and his colleagues believe IDPs create some of the infrared emission but cannot explain it all. Further, a continuously supplied source would migrate to lower depths, yet most of the emission is too high up, at pressures less than 2 millibars. And while the amount of water is roughly constant across the southern hemisphere, the emission gradually weakens northward until it’s less than half as strong. It’s not simply that Jupiter’s bottom half is hotter — there’s just more water down there. As the researchers note, “At least 95% of the observed water comes from the SL9 comet and subsequent (photo)-chemistry in Jupiter’s stratosphere according to our models, as of today.
Taken together, they conclude, these observations offer “clear evidence that a recent comet … is the principal source of water in Jupiter. What we observe today is a remnant of the oxygen delivery by the comet at 44°S in July 1994.”
Comet ISON is not brightening as much as expected, suggesting it will not be as spectacular as some had hoped.
Comet ISON is not brightening as much as expected, suggesting it will not be as spectacular as some had hoped.
Comet ISON is not brightening as much as expected, suggesting it will not be as spectacular as some had hoped.
A newly discovered comet has an orbit that might collide with Mars in October 2014.
Boom! A newly discovered comet has an orbit that might have it collide with Mars in October 2014.
Boom! A newly discovered comet has an orbit that might have it collide with Mars in October 2014.
The comet of the century?
I reported on the discovery of Comet ISON back in September, noting then the possibilities that this could become one of the brightest comets in years, while giving its show in primetime for the northern hemisphere. As this article also notes, this show could also be a dud, as has happened before. Stay tuned.
I reported on the discovery of Comet ISON back in September, noting then the possibilities that this could become one of the brightest comets in years, while giving its show in primetime for the northern hemisphere. As this article also notes, this show could also be a dud, as has happened before. Stay tuned.
“Comet Hergenrother is splitting apart.”
Astronomers have identified the same kind of minerals found in comets in the dusty disk surrounding the nearby star Beta Pictoris.
Astronomers have identified the same kind of minerals found in comets in our solar system in the dusty disk surrounding the nearby star Beta Pictoris.
Astronomers have identified the same kind of minerals found in comets in our solar system in the dusty disk surrounding the nearby star Beta Pictoris.
Amateurs astronomers have once again captured images of an impact of something on Jupiter.
Amateurs astronomers have once again captured images of a major impact of something on Jupiter.
Amateurs astronomers have once again captured images of a major impact of something on Jupiter.
Catching the death of a comet
Catching the death of a comet.
Catching the death of a comet.
The view of Comet Lovejoy from ISS
The view of Comet Lovejoy from ISS. With video.
The view of Comet Lovejoy from ISS. With video.
Comet Lovejoy lost its tail in skimming through the Sun’s atmosphere
Comet Lovejoy lost its tail in skimming through the Sun’s atmosphere Thursday.
Comet Lovejoy lost its tail in skimming through the Sun’s atmosphere Thursday.
Comet Elenin is no more
Chicken Little wrong again! Comet Elenin is no more.
Chicken Little wrong again! Comet Elenin is no more.
Water from comets
New results using the Herschel Space Telescope suggest that Earth’s water was brought here by comets.
New results using the Herschel Space Telescope suggest that Earth’s water was brought here by comets.
Comets Elenin & Garradd Now Showing in Night Sky
Get out those binoculars! Two comets, Elenin and Garradd, are now showing in the night sky.
Get out those binoculars! Two comets, Elenin and Garradd, are now showing in the night sky.
The Pan-STARRS Telescope has found comet that might provide a show in 2013
The Pan-STARRS Telescope has found a comet that might provide us all a show in 2013.
The Pan-STARRS Telescope has found a comet that might provide us all a show in 2013.
Stardust’s images show that Deep Impact burst underground bubbles on Comet Tempel 1
Pop! Analysis of the images that Stardust took of Comet Tempel 1 strongly suggest that when Deep Impact hit the comet’s surface it broke open several underground cavities that then burst like balloons.
Pop! Analysis of the images that Stardust took of Comet Tempel 1 strongly suggest that when Deep Impact hit the comet’s surface it broke open several underground cavities that then burst like balloons.
Observations of Comet Hale-Bopp at 30 AU
In a paper published tonight on the Los Alamos astro-ph preprint website, astronomers described new observations of Comet Hale-Bopp at a distance of 30 astronomical units, or 2.8 billion miles, from the sun. Their conclusions:
- These observations were the most distant detection of any known comet.
- The comet’s starlike appearance and its drop in brightness since the last observations suggest that the comet has finally ceased, or is about to cease, all activity, and that they are now looking directly at the comet’s nucleus instead of the coma cloud surrounding it.
- Nonetheless, the comet is brighter than expected, which also suggests that a thin layer of new ice covers its surface and thus increases its albedo.
To quote the paper, “Observing Hale-Bopp in a completely frozen state would be extremely important because a thick coma was constantly present during the entire appariation [Ed. the fly-by of the Sun]. The coma obscured the nucleus which was not observed directly. Lack photometric data of the bared nucleus, its size — one of the most important input parameter in activity models — remains uncertain.”
Evidence that liquid water once existed on a comet
Scientists have found strong evidence that liquid water once existed in the interior of a comet.
Scientists have found strong evidence that liquid water once existed in the interior of a comet.
The ripples in the rings of Saturn and Jupiter were caused by comets that hit them decades ago
The ripples in the rings of Saturn and Jupiter were caused by comet impacts decades ago.
The ripples in the rings of Saturn and Jupiter were caused by comet impacts decades ago.
Stardust to end its mission after twelve years
Stardust has ended its mission after twelve years and two comet flybys.
Ground controllers will command the spacecraft to fire up its four rocket thrusters one last time at 7 p.m. EDT (2300 GMT) today to use up its remaining fuel. Engineers plan to watch closely while the probe’s propellant tank ran dry to help future missions gauge their fuel reserves more precisely.
Stardust has ended its mission after twelve years and two comet flybys.
Ground controllers will command the spacecraft to fire up its four rocket thrusters one last time at 7 p.m. EDT (2300 GMT) today to use up its remaining fuel. Engineers plan to watch closely while the probe’s propellant tank ran dry to help future missions gauge their fuel reserves more precisely.
Stardust images of comet locate crater from Deep Impact’s impact
More news from Stardust: scientists have now identified what they think is the crater produced by Deep Impact’s impact in 2005. Key quote:
The images revealed a 150-metre-wide crater at the Deep Impact collision point that was not present in 2005. The crater is a subtle feature in the images, but it appears consistently in multiple views from the spacecraft. “So I feel very confident that we did find the [impact] site,” said mission member Peter Schultz of Brown University in Providence, Rhode Island, at a press briefing on Tuesday. The crater’s features are “subdued” rather than sharply defined, like those of craters made in hard materials like rock. “The message is: This surface of the comet where we hit is very weak,” said Schultz. The crater also has a small mound in its middle, indicating that some of the material thrown up by the impact was drawn by the comet’s gravity back down into the crater, he said: “In a way, it partly buried itself.”
More news from Stardust: scientists have now identified what they think is the crater produced by Deep Impact’s impact in 2005. Key quote:
The images revealed a 150-metre-wide crater at the Deep Impact collision point that was not present in 2005. The crater is a subtle feature in the images, but it appears consistently in multiple views from the spacecraft. “So I feel very confident that we did find the [impact] site,” said mission member Peter Schultz of Brown University in Providence, Rhode Island, at a press briefing on Tuesday. The crater’s features are “subdued” rather than sharply defined, like those of craters made in hard materials like rock. “The message is: This surface of the comet where we hit is very weak,” said Schultz. The crater also has a small mound in its middle, indicating that some of the material thrown up by the impact was drawn by the comet’s gravity back down into the crater, he said: “In a way, it partly buried itself.”
Stardust’s images of Comet Tempel 1
The images from Stardust’s flyby of Comet Tempel 1 are now available. I think the image below is the best, as it shows many details of the presently inactive comet surface. Scientists will need a bit of time now to compare these features with those imaged during the flyby of Deep Impact back in 2005.
First images from Stardust of Comet Tempel 1
The first images from Stardust of Comet Tempel 1 have been released. More to come later today.
Update: some glitch is delaying the download of the images. Instead of arriving as programmed, they are arriving in the order taken.
The first images from Stardust of Comet Tempel 1 have been released. More to come later today.
Update: some glitch is delaying the download of the images. Instead of arriving as programmed, they are arriving in the order taken.
How to Watch NASA’s Comet Tempel 1 Flyby
How to watch Stardust’s Comet Tempel 1 flyby tonight.
How to watch Stardust’s Comet Tempel 1 flyby tonight.
NASA Probe Set for Big Valentine’s Day Date With a Comet
While politicians argue budgets here on Earth, the NASA probe Stardust is zooming in on its flyby of Comet Tempel 1 tonight.
While politicians argue budgets here on Earth, the NASA probe Stardust is zooming in on its flyby of Comet Tempel 1 tonight.
Stardust refines its flight path towards comet Tempel
On Monday Stardust did a final mid-course correction in anticipation of its February 14 fly-by of of Comet Tempel 1.
On Monday Stardust did a final mid-course correction in anticipation of its February 14 fly-by of of Comet Tempel 1.
SOHO Spacecraft Discovers Its 2,000th Comet
The SOHO spacecraft, in space monitoring the Sun since 1995, has discovered its 2000th comet!
The SOHO spacecraft, in space monitoring the Sun since 1995, has discovered its 2000th comet!
An asteroid discovered more than 100 years ago is actually an extinct comet coming back to life
An asteroid discovered more than 100 years ago is actually an extinct comet. And it is coming back to life!
An asteroid discovered more than 100 years ago is actually an extinct comet. And it is coming back to life!
Dark Jupiter May Haunt Edge of Solar System
A dark Jupiter may haunt the edge of the solar system.
A dark Jupiter may haunt the edge of the solar system.
A snowstorm in space
Almost literally, the probe Deep Impact flew through a snowstorm when it flew past Comet Hartley 2 on November 4. Below is one of the best pictures from the moment. More images can be found here. Key quote:
[The images] revealed a cometary snow storm created by carbon dioxide jets spewing out tons of golf-ball to basketball-sized fluffy ice particles from the peanut-shaped comet’s rocky ends. At the same time, a different process was causing water vapor to escape from the comet’s smooth mid-section. This information sheds new light on the nature of comets and even planets.
Note that all the close-up images taken by Deep Impact are going to be slightly out of focus, as the camera was launched with a defect.