Close Mars Means Close-Up Pictures

Guttata writes " space.com has posted 1 of 2 images taken by Hubble last night, dubbed the best Mars globe photo ever taken. The second image will be posted at 4 p.m. ET. Cool!" aderuwe points to a report on the Hubble site itself. Finally, dpp writes "Space.com is reporting how astronomers using the UK Infrared Telescope (UKIRT) here at the Joint Astronomy Centre have made what are thought to be the sharpest ground-based images of Mars to date. They'll be studying the spectra of the infrared light to look for the signatures of minerals that would indicate the past presence of liquid water, which could have hosted life."

Comments

Search for life in Europa instead

[Brahmastra]

Europa looks like a far better candidate for water and life than mars. We should start sending probes to land on Europa as soon as possible.

Re:Search for life in Europa instead

[assaultriflesforfree]

It might be easier to look for life on Europa than Mars, actually. I got to have lunch with Freeman Dyson a few months ago, and we talked about some of the work (which I hope I'm not misrepresenting) he's done with the JPL on the life on Europa problem. As I understood him, a big problem is the cost of sending something way out there that can land, drill down, and send back some useful data. His team eventually decided that, 1) Water's way below the surface; that's where the life's going to be, and 2) It's going to have to collect light on the surface, and even there, sunlight's a little scarce. They envisioned these sort of gigantic solar collectors, almost like satellite dishes, protruding up through the surface where they could collect light. A neat feature is that anything that collects light also reflects it when observed properly, a la a rabbit in headlights. His idea was to just send a little probe and have it lined up so that the Sun, the probe, and Europa are all in colinear positions. If, as it comes into position, some glaring is obsreved on the surface, it might mean there's a good chance of life. Anybody know more about this? Am I completely off in what I've said?

A close-up of Mars doesn't seem like it will provide the same insight, unfortunately.

Re:Search for life in Europa instead

[Zathrus]

Er... if I read what you wrote correctly, then Dyson was theorizing on some form of water life that can tunnel through a few kilometers of ice and extend a probiscus into near vacuum that would act as a solar collector.

While that sounds absurd, I won't dismiss it out of hand. Instead I'll dismiss it for other reasons. I find it unlikely that no such structure has been observed from any of the probes we've sent out (Voyager 1/2, Galileo). They may not have been in the optimal position for such an observance, but you'd still think something would show up. After all, there's no reason to be camoflauged on the surface, right? No predators there.

Second, I find it unlikely that any life on Europa will be garnering energy from the Sun. There's just not enough of it, and there's that several kilometers of ice issue. Too much energy expended to recover from sunlight. I'd think it more likely that there are some bacteria living near the rocky core off the magma/steam vents -- if there are any. I don't know if Europa is tectonically active or not. If it's not, then I'm going to vote for a dead world. I just don't see there being enough energy input to sustain life for a long period of time, especially given occasional disruptions like meteor impacts cracking the ice (which is probably fairly violent and deadly to any life near the crack).

Of course, I could be wrong and there could be some really amazing life forms there. It's worth investigating, but it's going to be hard to do. Not only do you have to surmount the environmental challenges a previous poster mentioned, you also have to be 100% positive you don't introduce a foreign life form - which could either give you a false positive or kill off what's there already (low likelihood -- I suspect Europa's environment is too hostile to Earth bred bacteria, but we've been surprised before).

post processing?

[MarcoAtWork]

in the article it says that (due to the long exposures & mars' rotation) the photos needed to be post-processed to make them sharp: does anybody know more about the techniques used for this? I can't quite think of a method that one can use to accomplish this...

Re:post processing?

[mph]

Straight up image stacking or averaging does not remove the effects of atmospheric turbulence. HTH.

It can, if the individual exposures are short enough (something like 0.1 seconds each). On those timescales, seeing (turbulence) causes an image to jump around. You can shift them all back into alignment before stacking them.

As you expose longer, you add up light from your star as it's "jumped around" to lots of positions. The result is a smeared-out image; adding multiple exposures will not help at this point, as you said.

A technique called "speckle interferometry" was used at Keck to take advantage of short exposures to get around seeing. Also, the first order adaptive optics correction, "tip-tilt," simply compensates for the image jumping around on these timescales.

Another way that multiple short exposures helps is that seeing is variable; some instants it will be good, then a second later it's poor. So you can take a couple of hundred 0.1 second images, take the 20 with the best seeing, and then just use those in your final, combined image (after shifting them to be properly aligned). With longer exposures, you'll average over both good and bad seeing, and they'll all look nearly the same, so this technique won't work.

Gas versus dust

[HarveyBirdman]

The Martian sky looks reddish from the ground because of the dust content. From space (or Earth) we are seeing the upper atmosphere which is just gasses (CO2 mainly), and gasses scatter the blue light (look up "Rayleigh scattering").

Actually, there are some on the fringe (but not quite into "the face on Mars" fringe) insists that the Martian sky *is* blue from the ground. They claim that NASA's color correction of the incoming images, dating all the way back to the Viking landers, is off. The URL escapes me at the moment, I'm afraid.

Keck observatory & optical interferometry

[TheOrquithVagrant]

I'd love to see how the images the Keck observatory, with its adaptive optics and 10-meter mirrors, and how they would stack up against the hubble images.

Better yet, the images they could produce if the Keck optical interferometer was fully operational. I know taking pictures of things inside our solar system definitely is not what they're aiming for with the interferometer, but it would still be very interesting to see if a ground based "virtual 85-meter mirror" could produce better results than an orbital telescope like hubble.

And STILL better - a space-based optical interferometry array! Imagine images of planets in OTHER solar systems with resolutions similar to the Mars pictures we're marveling at today... Interferometry is cool. I just hope I live to see a really big optical interferometer in orbit, and the images it will be able to snap.

Better stop now, starting to ramble... :)

Re:One thing that surprises me...

[ip_vjl]

It's not like Mars is within walking distance now. Even with this pass-by, it would still be a very lengthy journey for a person to take. Too long for any technology we have now to support.

And by the way, once they get there - they'll have to come back (since we don't have any way of setting up a permanent settlement) so they'd have to do that without the benefit of this close pass.

Re:Exploitable mineral content

[toddestan]

I've heard that if all the gold in Fort Knox was sitting on the moon, free for the taking, it would still not be profitable to go up there and get it.

I doubt Mars would be any different.

Amateur Astronomer Images of Mars

[fishbonez]

Even the images now being produced by amateur astronomers are really excellent as a result of the close proximity of Mars. An archive amateur Mars images can be found at the International Marswatch site. Looking back through the archive, you can see how much more detail can be seen in the images as Mars has drawn nearer.