5 ms·

Welcome to a comet

387 points by jbogp 12y ago

jbogp 12y ago
That's a great achievement in any case. I'm just slightly worried from the looks of this picture that Philae actually stabilized on its side. Also the large amount of shadow in the area is worrisome for the solar panels to function properly. Press conference with the release of a full panorama (which will hopefully not confirm the side landing) is scheduled for 1400 CET.
- mhandley 12y ago
  The sunlight appears to be coming from behind and to the left of Philae in this picture, at a fairly low angle, so the back of it should (I hope) be reasonably illuminated at the moment. It's definitely not clear from this picture which way is "up". It looks to me like up may be towards the top right of the picture, in which case Philae may be at a 45 degree angle. But I'm probably wrong - the full panorama should tell all.
  - mhandley 12y ago
    After staring at the image a lot more, I realised I'm completely wrong. The leg reveals which way the lighting is coming from - above, slightly to the left, and probably slanting slightly into the camera. So my original interpretation of the orientation cannot be correct. The real question is whether the picture should be rotated 90+ degrees clockwise.
  - smoyer 12y ago
    The lander's leg is very well lit and there is clearly nothing underneath it. The antenna appears (based on it's end converging with it's own shadow) to be resting against either a rock or the surface. I'm not a rocket scientist ... I hope I'm grossly misinterpreting this image!
jbogp 12y ago
Also very interesting, if you look at the high-res picture and zoom at the bottom right, you'll notice some sort of cable on the ground/boulder. This could be the cable from one of the harpoons that may have fired but didn't anchor themselves, or it could be a feature attached to Philae that's in the field of vision.
- Luc 12y ago
  It looks like it's resting on one of the antennae. You can see its shadow underneath it.
- andrewd18 12y ago
  That's one of the audio cables from the sound stage. If you look closely you can see the shadow of a boom mic on one of the rocks.
  - mirkules 12y ago
    My first thought was: "Why would they need a mic? There's no sound in space" and then I felt the whoosh over my head. Well done.
lentil_soup 12y ago
Curious question, is the light in the picture all from the Sun or do they use something artificial?
- jbogp 12y ago
  All from the sun.
deleted 12y ago
[deleted]
binarymax 12y ago
The sheen coming from the surface where light hits is indicative of some interesting materials on that comet. Looking forward to more photos and especially analysis of the surface composition!
Lrigikithumer 12y ago
You know I have some bad days some times, but seeing shit like this just makes me think "What a fucking time to be alive!" It's truly incredibly and is sometimes that kick in the pants I need to keep on going. We are living in a golden age of humanity right now, at no point before in human history have so many people had such an incredible quality of life and never before has man been doing such incredible feats and have the ability to reach a worldwide audience almost instantaneously. The fact that just a few hours ago a human designed space craft landed on a comet, after decades of work and I can receive the images fresh from the great minds that brought us this feat, while laying in bed dicking about on my phone, it's just pure and simply astounding. For all our flaws I love humans and I am so excited to see what the future holds. Back to the comet, any word on what happened to the harpoons? I heard there was a misfire or they didn't fire or something? Any idea how that's affected the landing as of yet?
- kissickas 12y ago
  I don't think we've gotten any further details than the fact that they didn't fire when they should have. There's a press conference at 2 pm CET.
- vital101 12y ago
  I'm not sure about that status of the harpoons, but I generally use http://reddit.com/r/space http://reddit.com/r/space to keep up with all of my space related news. Article quality is generally very high and there are a lot nice folks over there who answer questions in the comments.
  - Lrigikithumer 12y ago
    Thanks, I'll be sure to keep my eye on that sub
- badname 12y ago
  Yes it is golden age as long as you disregard percentages and trend. "Some 805 million people in the world do not have enough food to lead a healthy active life. That's about one in nine people on earth." http://www.wfp.org/hunger/stats http://www.wfp.org/hunger/stats Economy seems like a boiler ready to explode, rich-poor chasm is widening like hell. Global peace doesn't look very rosy either. Not to mention what's happening on the environmental front. All in all, sorry but I cannot feel the joy of "us humans doing well". We don't. Some technical sectors are doing well - that's all. Socially, ethically, politically we're still at middle ages and speeding backwards. My 2 cents (which is most than millions of people can spare ;-) )
muyuu 12y ago
Does it have a colour camera? or maybe it's a bandwidth-saving decision to transmit only B&W? or because of the lighting?
- wlievens 12y ago
  Apparently the visible light sensor has RGB color filters. http://nssdc.gsfc.nasa.gov/nmc/experimentDisplay.do?id=PHILAE%20%20%20-02 http://nssdc.gsfc.nasa.gov/nmc/experimentDisplay.do?id=PHILA... I would guess these are probably not a Bayer filter pattern, but filters that are mechanically swapped.
  - narag 12y ago
    I remember having read long time ago that superposing B&W images took with those filters gives an also B&W image that our brain perceives as coloured. Does anybody know if this is correct or what's the name of that effect?
    - wlievens 12y ago
      I'm not sure. I thought of the "False Color" concept, but that's pretty much the exact opposite of what you said. http://en.wikipedia.org/wiki/False_color http://en.wikipedia.org/wiki/False_color
    - noamyoungerm 12y ago
      If you send three grayscale images, each one taken through a different colored filter, you can reconstruct a color image back on earth by setting the red channel, green channel, and blue channel of the image to be each one of the colored filters you used to capture the image. This isn't a grayscale image that our brain perceives on color, but rather several grayscale images, each colored separately to combine into a color image. I seriously doubt an actual effect exists that makes us believe black and white images are actually colored.
- Zeebrommer 12y ago
  The pictures taken by Rosetta are BW. From [0]: "Some light contrast enhancements have been made to emphasise certain features and to bring out features in the shadowed areas. In reality, the comet is extremely dark -– blacker than coal. The images, taken in black-and-white, are grey-scaled according to the relative brightness of the features observed, which depends on local illumination conditions, surface characteristics and composition of the given area. Some slight vignetting can also be seen in the corners of some images." So possibly Philae has a similar system. [0] https://www.flickr.com/photos/europeanspaceagency/15739966376/in/set-72157638315605535 https://www.flickr.com/photos/europeanspaceagency/1573996637...
fit2rule 12y ago
Looks like a pretty rough place to land - I wonder though if this is one of the 'bounce' phases of the landing, and maybe what ended up happening was that it was more of a tumble, due to surface features snagging a leg, or something.. I must admit that during the approach, the landing site looked to me like it might have been 'pretty smooth', like it was a plane of material that didn't look too jagged and nasty, but this photo just looks like we landed in a pretty rough spot. Regardless, seems like some science is going to get done anyway, and that sure is exciting! Can't wait for 14:00 and see some new pics ..
rurban 12y ago
So "Armageddon" was right. A comet looks much more interesting than the Moon or Mars. No boring dunes and flat sands, really rocky.
- Lambdanaut 12y ago
  I'd say this is a far-cry from that dramatization, but hey, they weren't as far off as we thought! Comet 67P seems a lot more rugged than previous comets we've been to.
IndianAstronaut 12y ago
Moon, Mars, Venus, Titan, and now comet 67p. Absolutely amazing.
- avian 12y ago
  Don't forget asteroid Itokawa. https://en.wikipedia.org/wiki/Hayabusa https://en.wikipedia.org/wiki/Hayabusa
  - NietTim 12y ago
    I think he was talking about actual landings. Hayabusa/its lander MINERVA failed to land
    - avian 12y ago
      > In November 2005, it landed on the asteroid and collected samples in the form of tiny grains of asteroidal material, which were returned to Earth aboard the spacecraft on 13 June 2010. (from the Wikipedia article) Yes, the lander failed, but the bus itself did land on the surface. It was a sample return mission which is in many ways a greater feat.
    - eggy 12y ago
      MINERVA failed to land, but Hayabusa made a series of soft landings on to the asteroid in 2005, and collected samples that were returned to Earth. Pretty amazing in its own right and time.
- jeffwass 12y ago
  Space probe NEAR-Shoemaker landed on asteroid Eros in 2001! What is amazing about this landing is that the probe had no landing gear, no shock absorbers, and was not designed in any way to land. NASA engineers tuned the orbit carefully and slowly and we're able to match velocities for a soft landing for what was otherwise supposed to be an orbiting spacecraft. http://en.m.wikipedia.org/wiki/NEAR_Shoemaker http://en.m.wikipedia.org/wiki/NEAR_Shoemaker (Edit - fixed asteroid name)
afoot 12y ago
That single image is quite impactful if you know the background to the project. It's like something out of a movie.
gokhan 12y ago
From Reddit[1]: "Got fresh news from the team, they are broadcasting live right now on french TV ! Philae landed, and bounced slowly for (1-2-? hours), and travelled 1km away the targetted site. Yes 1000m. Then know this because of the datas from the radar. It's now stopped slanted, some cams are shooting the sky, other the ground, and other nearby rocks, as seen on the first photo. It's inside some kind of cave/hole, not much sun for the solar panels. EDIT1: It landed on the core of the comet, it sees the light from the sun for about 1 to 2 hours per day. In the next days/week the angle of the comet will change/sun, and it very likely the solar panel will get more sunlight so more power for the probe. EDIT2 : Many labs are performing right now and performed the whole night. For now they put the drilling on hold since they don't know if it's tied to the ground or not. Drilling op was also power hungry so it's kinda a good thing it's on hold since there's not much sun available for the panels. Battery life been re-estimated to 50-55hours due to the lack of sunlight. This time includes the 7 hours of descent.They are constantly adjusting missions goals, depending on conditions, power available, etc, EDIT3 : The probe has been working to gather scientifict datas the whole time, including during the bounces. There's already a large amount of datas available, whatever happens next. EDIT4 : It's resting on "hard" ground, with a layer of dust about 30cm, and that's good news because it allows measurements to proceed as planned. As in, it's not burried into soft soil. EDIT5 : Solar panels are deployed, radio link is up and running, but the fact the probe is slanted/in a hole/random ground limits the time it can communicate with the orbiter, but that's not jeopardizing the mission. There's already a lot of datas transmitted successfully to the orbiter. Contact between the orbiter and the probe can be approximately done twice per day. EDIT6 : The first place it touched the comet was exaclty where it was planned, flat and cosy, too bad it didn't harpoon there. EDIT7 : Next contact will be near 19:30GMT, until 23:45GMT approx. This night they made contact with the probe (from the orbiter) at about 4:00GMT, and at 5:30GMT they had safely recovered all the datas from the first batch of tests." [1] http://www.reddit.com/r/space/comments/2m63hd/first_civa_image_confirming_that_philae_is_on/cm19x10 http://www.reddit.com/r/space/comments/2m63hd/first_civa_ima...
- valevk 12y ago
  > travelled 1km away the targetted site. Yes 1000m. Wow, I think this is great luck, that the probe is still on the comet, and even seems to work properly.
TomGullen 12y ago
I'm curious to know, how far will the landing affect it's orbit?
- sp332 12y ago
  The probe is very small compared to the comet, so probably hardly at all. http://www.esa.int/spaceinimages/Images/2014/09/Philae_s_primary_landing_site_in_context http://www.esa.int/spaceinimages/Images/2014/09/Philae_s_pri...
- flinty 12y ago
  are you thinking if we can potentially deflect comets?
  - TomGullen 12y ago
    Yep :)
deleted 12y ago
[deleted]
zachrose 12y ago
It almost seems like "landing" is too strong a word: Philae has a mass of 100kg and the gravity of Churyumov–Gerasimenko is estimated to be 10e−3 m/s2, which comes out to a weight of 3.5 ounces, or the equivalent of 100 grams on earth. Let's hope it holds!
- stromgo 12y ago
  10e-3 m/s^2 is hard to believe, as the lander would have to be ~250m away from the center of mass [1]. More likely it is 2500m away from the center of mass, giving 6.67e-11 * 1.0e13 / 2500 ^ 2 = 0.0001 m/s^2, so about 1 gram. [1] I can't find a reliable estimate of the surface gravity online, but the mass estimate at http://blogs.esa.int/rosetta/2014/08/21/determining-the-mass-of-comet-67pc-g/ http://blogs.esa.int/rosetta/2014/08/21/determining-the-mass... seems accurate.
- ctdonath 12y ago
  Thanks to the sorta dumbbell shape, depending on where Philae landed the apparent gravity may be a LOT less, should a considerable amount of the comet's mass be "above" the lander. (Think "what's the pull of gravity in the center of a planet?")
netcan 12y ago
This is exciting. I'm excited. My reaction to this photo is a little funny. Basically: "Rocks! We have rocks too! Yours look a lot like ours." I have this desire to find things in common. Like flirting.
netcan 12y ago
This is exciting. I'm excited. My reaction to this photo is a little funny. Basically: "Rocks! We have rocks too! Yours look a lot like ours." I have this desire to find things in common. Like flirting.
harisamin 12y ago
This is pretty crazy and awesome!
jamesfisher 12y ago
Possibly stupid question: why are all the images greyscale? Could we not send a color camera? Or is the comet very grey? Or does color not work in space?
- NeverEnough 12y ago
  color works just fine I know that sometimes, images are first sent in black and white to save on data, color is sent later. Hubble apparently only does black and white. color images can be obtained using a technique involving two of its black and white images. But that is a telescope, probably not similar. http://hubblesite.org/gallery/behind_the_pictures/meaning_of_color/ http://hubblesite.org/gallery/behind_the_pictures/meaning_of... the comet could just be grey, not sure about that one.
  - mnw21cam 12y ago
    Also, cameras are much more sensitive and higher resolution if they are B&W. A colour camera has to have a bayer matrix filter in front of the pixels (or some other weird trick) which throws away a load of the light. Generally, when telescopes want colour images, they will take several pictures with different filters in front of the telescope, then combine them. This is useful because you can have a wide selection of filters, including ones for specific science-related wavelengths, like hydrogen alpha, or oxygen emissions. A normal colour camera is limited to three filters.
- hahainternet 12y ago
  The comet is in fact very very black, but pretty much all cameras are greyscale. Most 'colour' cameras are just a series of filters placed over the pixels to sense only light of the desired colour (usually RGB) When science has to be done, it's easier to have a selectable set of filters you can put in front of the whole sensor at once. This way you can use the full sensor resolution and you can have a wider variety of filters. They also tend to bring along spectrometers of some description which are again much much more useful.
lostInComm 12y ago
Ok this has been bugging me... What is a "CIVA Image"? Everyone is using the term - but not explaining what it is!
- dennismp 12y ago
  I think its referring to this: http://www.esa.int/Our_Activities/Space_Science/Rosetta/CIVA http://www.esa.int/Our_Activities/Space_Science/Rosetta/CIVA
deleted 12y ago
[deleted]

387 points by jbogp 12y ago

jbogp 12y ago

That's a great achievement in any case. I'm just slightly worried from the looks of this picture that Philae actually stabilized on its side. Also the large amount of shadow in the area is worrisome for the solar panels to function properly. Press conference with the release of a full panorama (which will hopefully not confirm the side landing) is scheduled for 1400 CET.

mhandley 12y ago
The sunlight appears to be coming from behind and to the left of Philae in this picture, at a fairly low angle, so the back of it should (I hope) be reasonably illuminated at the moment. It's definitely not clear from this picture which way is "up". It looks to me like up may be towards the top right of the picture, in which case Philae may be at a 45 degree angle. But I'm probably wrong - the full panorama should tell all.
- mhandley 12y ago
  After staring at the image a lot more, I realised I'm completely wrong. The leg reveals which way the lighting is coming from - above, slightly to the left, and probably slanting slightly into the camera. So my original interpretation of the orientation cannot be correct. The real question is whether the picture should be rotated 90+ degrees clockwise.
- smoyer 12y ago
  The lander's leg is very well lit and there is clearly nothing underneath it. The antenna appears (based on it's end converging with it's own shadow) to be resting against either a rock or the surface. I'm not a rocket scientist ... I hope I'm grossly misinterpreting this image!

jbogp 12y ago

Also very interesting, if you look at the high-res picture and zoom at the bottom right, you'll notice some sort of cable on the ground/boulder. This could be the cable from one of the harpoons that may have fired but didn't anchor themselves, or it could be a feature attached to Philae that's in the field of vision.

Luc 12y ago
It looks like it's resting on one of the antennae. You can see its shadow underneath it.
andrewd18 12y ago
That's one of the audio cables from the sound stage. If you look closely you can see the shadow of a boom mic on one of the rocks.
- mirkules 12y ago
  My first thought was: "Why would they need a mic? There's no sound in space" and then I felt the whoosh over my head. Well done.

lentil_soup 12y ago

Curious question, is the light in the picture all from the Sun or do they use something artificial?

jbogp 12y ago
All from the sun.

deleted 12y ago

[deleted]

binarymax 12y ago

The sheen coming from the surface where light hits is indicative of some interesting materials on that comet. Looking forward to more photos and especially analysis of the surface composition!

Lrigikithumer 12y ago

You know I have some bad days some times, but seeing shit like this just makes me think "What a fucking time to be alive!" It's truly incredibly and is sometimes that kick in the pants I need to keep on going. We are living in a golden age of humanity right now, at no point before in human history have so many people had such an incredible quality of life and never before has man been doing such incredible feats and have the ability to reach a worldwide audience almost instantaneously. The fact that just a few hours ago a human designed space craft landed on a comet, after decades of work and I can receive the images fresh from the great minds that brought us this feat, while laying in bed dicking about on my phone, it's just pure and simply astounding. For all our flaws I love humans and I am so excited to see what the future holds. Back to the comet, any word on what happened to the harpoons? I heard there was a misfire or they didn't fire or something? Any idea how that's affected the landing as of yet?

kissickas 12y ago
I don't think we've gotten any further details than the fact that they didn't fire when they should have. There's a press conference at 2 pm CET.
vital101 12y ago
I'm not sure about that status of the harpoons, but I generally use http://reddit.com/r/space http://reddit.com/r/space to keep up with all of my space related news. Article quality is generally very high and there are a lot nice folks over there who answer questions in the comments.
- Lrigikithumer 12y ago
  Thanks, I'll be sure to keep my eye on that sub
badname 12y ago
Yes it is golden age as long as you disregard percentages and trend. "Some 805 million people in the world do not have enough food to lead a healthy active life. That's about one in nine people on earth." http://www.wfp.org/hunger/stats http://www.wfp.org/hunger/stats Economy seems like a boiler ready to explode, rich-poor chasm is widening like hell. Global peace doesn't look very rosy either. Not to mention what's happening on the environmental front. All in all, sorry but I cannot feel the joy of "us humans doing well". We don't. Some technical sectors are doing well - that's all. Socially, ethically, politically we're still at middle ages and speeding backwards. My 2 cents (which is most than millions of people can spare ;-) )

muyuu 12y ago

Does it have a colour camera? or maybe it's a bandwidth-saving decision to transmit only B&W? or because of the lighting?

wlievens 12y ago
Apparently the visible light sensor has RGB color filters. http://nssdc.gsfc.nasa.gov/nmc/experimentDisplay.do?id=PHILAE%20%20%20-02 http://nssdc.gsfc.nasa.gov/nmc/experimentDisplay.do?id=PHILA... I would guess these are probably not a Bayer filter pattern, but filters that are mechanically swapped.
- narag 12y ago
  I remember having read long time ago that superposing B&W images took with those filters gives an also B&W image that our brain perceives as coloured. Does anybody know if this is correct or what's the name of that effect?
  - wlievens 12y ago
    I'm not sure. I thought of the "False Color" concept, but that's pretty much the exact opposite of what you said. http://en.wikipedia.org/wiki/False_color http://en.wikipedia.org/wiki/False_color
  - noamyoungerm 12y ago
    If you send three grayscale images, each one taken through a different colored filter, you can reconstruct a color image back on earth by setting the red channel, green channel, and blue channel of the image to be each one of the colored filters you used to capture the image. This isn't a grayscale image that our brain perceives on color, but rather several grayscale images, each colored separately to combine into a color image. I seriously doubt an actual effect exists that makes us believe black and white images are actually colored.
Zeebrommer 12y ago
The pictures taken by Rosetta are BW. From [0]: "Some light contrast enhancements have been made to emphasise certain features and to bring out features in the shadowed areas. In reality, the comet is extremely dark -– blacker than coal. The images, taken in black-and-white, are grey-scaled according to the relative brightness of the features observed, which depends on local illumination conditions, surface characteristics and composition of the given area. Some slight vignetting can also be seen in the corners of some images." So possibly Philae has a similar system. [0] https://www.flickr.com/photos/europeanspaceagency/15739966376/in/set-72157638315605535 https://www.flickr.com/photos/europeanspaceagency/1573996637...

fit2rule 12y ago

Looks like a pretty rough place to land - I wonder though if this is one of the 'bounce' phases of the landing, and maybe what ended up happening was that it was more of a tumble, due to surface features snagging a leg, or something.. I must admit that during the approach, the landing site looked to me like it might have been 'pretty smooth', like it was a plane of material that didn't look too jagged and nasty, but this photo just looks like we landed in a pretty rough spot. Regardless, seems like some science is going to get done anyway, and that sure is exciting! Can't wait for 14:00 and see some new pics ..

rurban 12y ago

So "Armageddon" was right. A comet looks much more interesting than the Moon or Mars. No boring dunes and flat sands, really rocky.

Lambdanaut 12y ago
I'd say this is a far-cry from that dramatization, but hey, they weren't as far off as we thought! Comet 67P seems a lot more rugged than previous comets we've been to.

IndianAstronaut 12y ago

Moon, Mars, Venus, Titan, and now comet 67p. Absolutely amazing.

avian 12y ago
Don't forget asteroid Itokawa. https://en.wikipedia.org/wiki/Hayabusa https://en.wikipedia.org/wiki/Hayabusa
- NietTim 12y ago
  I think he was talking about actual landings. Hayabusa/its lander MINERVA failed to land
  - avian 12y ago
    > In November 2005, it landed on the asteroid and collected samples in the form of tiny grains of asteroidal material, which were returned to Earth aboard the spacecraft on 13 June 2010. (from the Wikipedia article) Yes, the lander failed, but the bus itself did land on the surface. It was a sample return mission which is in many ways a greater feat.
  - eggy 12y ago
    MINERVA failed to land, but Hayabusa made a series of soft landings on to the asteroid in 2005, and collected samples that were returned to Earth. Pretty amazing in its own right and time.
jeffwass 12y ago
Space probe NEAR-Shoemaker landed on asteroid Eros in 2001! What is amazing about this landing is that the probe had no landing gear, no shock absorbers, and was not designed in any way to land. NASA engineers tuned the orbit carefully and slowly and we're able to match velocities for a soft landing for what was otherwise supposed to be an orbiting spacecraft. http://en.m.wikipedia.org/wiki/NEAR_Shoemaker http://en.m.wikipedia.org/wiki/NEAR_Shoemaker (Edit - fixed asteroid name)

afoot 12y ago

That single image is quite impactful if you know the background to the project. It's like something out of a movie.

gokhan 12y ago

From Reddit[1]: "Got fresh news from the team, they are broadcasting live right now on french TV ! Philae landed, and bounced slowly for (1-2-? hours), and travelled 1km away the targetted site. Yes 1000m. Then know this because of the datas from the radar. It's now stopped slanted, some cams are shooting the sky, other the ground, and other nearby rocks, as seen on the first photo. It's inside some kind of cave/hole, not much sun for the solar panels. EDIT1: It landed on the core of the comet, it sees the light from the sun for about 1 to 2 hours per day. In the next days/week the angle of the comet will change/sun, and it very likely the solar panel will get more sunlight so more power for the probe. EDIT2 : Many labs are performing right now and performed the whole night. For now they put the drilling on hold since they don't know if it's tied to the ground or not. Drilling op was also power hungry so it's kinda a good thing it's on hold since there's not much sun available for the panels. Battery life been re-estimated to 50-55hours due to the lack of sunlight. This time includes the 7 hours of descent.They are constantly adjusting missions goals, depending on conditions, power available, etc, EDIT3 : The probe has been working to gather scientifict datas the whole time, including during the bounces. There's already a large amount of datas available, whatever happens next. EDIT4 : It's resting on "hard" ground, with a layer of dust about 30cm, and that's good news because it allows measurements to proceed as planned. As in, it's not burried into soft soil. EDIT5 : Solar panels are deployed, radio link is up and running, but the fact the probe is slanted/in a hole/random ground limits the time it can communicate with the orbiter, but that's not jeopardizing the mission. There's already a lot of datas transmitted successfully to the orbiter. Contact between the orbiter and the probe can be approximately done twice per day. EDIT6 : The first place it touched the comet was exaclty where it was planned, flat and cosy, too bad it didn't harpoon there. EDIT7 : Next contact will be near 19:30GMT, until 23:45GMT approx. This night they made contact with the probe (from the orbiter) at about 4:00GMT, and at 5:30GMT they had safely recovered all the datas from the first batch of tests." [1] http://www.reddit.com/r/space/comments/2m63hd/first_civa_image_confirming_that_philae_is_on/cm19x10 http://www.reddit.com/r/space/comments/2m63hd/first_civa_ima...

valevk 12y ago
> travelled 1km away the targetted site. Yes 1000m. Wow, I think this is great luck, that the probe is still on the comet, and even seems to work properly.

TomGullen 12y ago

I'm curious to know, how far will the landing affect it's orbit?

sp332 12y ago
The probe is very small compared to the comet, so probably hardly at all. http://www.esa.int/spaceinimages/Images/2014/09/Philae_s_primary_landing_site_in_context http://www.esa.int/spaceinimages/Images/2014/09/Philae_s_pri...
flinty 12y ago
are you thinking if we can potentially deflect comets?
- TomGullen 12y ago
  Yep :)

deleted 12y ago

[deleted]

zachrose 12y ago

It almost seems like "landing" is too strong a word: Philae has a mass of 100kg and the gravity of Churyumov–Gerasimenko is estimated to be 10e−3 m/s2, which comes out to a weight of 3.5 ounces, or the equivalent of 100 grams on earth. Let's hope it holds!

stromgo 12y ago
10e-3 m/s^2 is hard to believe, as the lander would have to be ~250m away from the center of mass [1]. More likely it is 2500m away from the center of mass, giving 6.67e-11 * 1.0e13 / 2500 ^ 2 = 0.0001 m/s^2, so about 1 gram. [1] I can't find a reliable estimate of the surface gravity online, but the mass estimate at http://blogs.esa.int/rosetta/2014/08/21/determining-the-mass-of-comet-67pc-g/ http://blogs.esa.int/rosetta/2014/08/21/determining-the-mass... seems accurate.
ctdonath 12y ago
Thanks to the sorta dumbbell shape, depending on where Philae landed the apparent gravity may be a LOT less, should a considerable amount of the comet's mass be "above" the lander. (Think "what's the pull of gravity in the center of a planet?")

netcan 12y ago

This is exciting. I'm excited. My reaction to this photo is a little funny. Basically: "Rocks! We have rocks too! Yours look a lot like ours." I have this desire to find things in common. Like flirting.

netcan 12y ago

harisamin 12y ago

This is pretty crazy and awesome!

jamesfisher 12y ago

Possibly stupid question: why are all the images greyscale? Could we not send a color camera? Or is the comet very grey? Or does color not work in space?

NeverEnough 12y ago
color works just fine I know that sometimes, images are first sent in black and white to save on data, color is sent later. Hubble apparently only does black and white. color images can be obtained using a technique involving two of its black and white images. But that is a telescope, probably not similar. http://hubblesite.org/gallery/behind_the_pictures/meaning_of_color/ http://hubblesite.org/gallery/behind_the_pictures/meaning_of... the comet could just be grey, not sure about that one.
- mnw21cam 12y ago
  Also, cameras are much more sensitive and higher resolution if they are B&W. A colour camera has to have a bayer matrix filter in front of the pixels (or some other weird trick) which throws away a load of the light. Generally, when telescopes want colour images, they will take several pictures with different filters in front of the telescope, then combine them. This is useful because you can have a wide selection of filters, including ones for specific science-related wavelengths, like hydrogen alpha, or oxygen emissions. A normal colour camera is limited to three filters.
hahainternet 12y ago
The comet is in fact very very black, but pretty much all cameras are greyscale. Most 'colour' cameras are just a series of filters placed over the pixels to sense only light of the desired colour (usually RGB) When science has to be done, it's easier to have a selectable set of filters you can put in front of the whole sensor at once. This way you can use the full sensor resolution and you can have a wider variety of filters. They also tend to bring along spectrometers of some description which are again much much more useful.

lostInComm 12y ago

Ok this has been bugging me... What is a "CIVA Image"? Everyone is using the term - but not explaining what it is!

dennismp 12y ago
I think its referring to this: http://www.esa.int/Our_Activities/Space_Science/Rosetta/CIVA http://www.esa.int/Our_Activities/Space_Science/Rosetta/CIVA

deleted 12y ago

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