asterroc: (Astro - H-alpha)
1) They've cried wolf enough times at this point that I'm always skeptical about every new announcement.

2) This is yet more indirect evidence - they've found visual evidence of changing patterns that could look like streams, and in the same areas spectra give the chemical "fingerprints" of assorted salts (not table salt, NaCl, but chemically similar) which as far as we know can only form in water.

To me, if the evidence is indirect, we will need a lot more of it than if we actually saw liquid H2O flowing and used spectra to confirm it was water. Right now we have circumstantial evidence of things that look like stream beds (but could be caused by other liquid solvents, or a remote chance they're caused by wind), and we a number of chemicals which as far as we know can only form in water (not only these salts, but also the hematite blueberries from a few years back). However the hypothesis "this can only form in water" is one of those things we can never actually prove true, just eliminate more and more untrue possibilities.

So to me as a watcher of all this, it's just a waiting game. If there really is liquid water, then little pieces of evidence like this (and the hematite blueberries) will continue to build up until at some point the molehill has become a mountain and it'll be generally accepted by all planetary astronomers (and then all astronomers, and then the world) that yes, there's liquid water on Mars.

3) Water is a key building block for life, so the next question is "is there life on Mars?" Assuming this liquid water exists, it is transient - it's seasonal, appearing only in local summer. If it's transient liquid water, I will need to see some pretty solid evidence to believe that there is current single-cellular life. If it's persistent liquid water I will switch over entirely and I will assume that there's single-cellular life until proven otherwise. Even if it didn't evolve on Mars, we've sent missions there and it's impossible to sterilize everything completely, plus bits of Earth have been knocked off from impacts and landed on Mars so it might've been seeded with Earth life millennia ago. If it's possible to sustain some form of life on Mars, I guarantee you that it's there.

Originally posted on Dreamwidth. comment count unavailable comments there. Comment here or there.
asterroc: (Astro - H-alpha)
Post copypasted from Tumblr b/c I'm just that excited.

OMFG I’m so excited! New Horizons flew by Pluto about 2.5 hours ago. It’s going to remain pointed at Pluto for another 5 hours or so to get as much data as possible, and then the craft is going to slew around and spit back all the images and other data to Earth, and then it’s going to take another 5 hours for the signal to get here.

Among the amazing discoveries so far, we already have that Pluto is larger than previously thought. We knew that Eris was the most massive Kuiper Belt Object - mass is easy to get when an object has moons, and Pluto has five (Charon, Nix, Hydra, Styx, Kerberos) and Eris one (Dysnomia).

Read more... )

How exciting is that!?

Originally posted on Dreamwidth. comment count unavailable comments there. Comment here or there.
Just watched the last Space Shuttle launch, Atlantis, on TV.

In my entire life I have now watched a grand total of three Space Shuttle launches (all on TV):
* Challenger, 1986
* Discovery, 2005
* Atlantis, 2011

According to my recollection, I was in third grade when my teacher decided that we would all crowd around the little 10" classroom TV to watch the first teacher go into space. We all know how that ended. I remember the entire classroom being silent for a long time before my teacher said anything.

For nearly two decades after that I was mostly against human spaceflight. It cost too much money, there was too little return on investment, and it was too risky, said the emotional side of me. The intellectual side said that others found it inspiring so we should continue human spaceflight to drive funding of real astronomy, and I also thought it was important to someday colonize other places than Earth so we must start that somewhere.

2005 was Discovery's "Return to Flight" mission, after the 2003 Columbia disaster. That summer I happened to be teaching astronomy at a nerd camp, so my TA on his own initiative arranged to have the class crowd around a TV screen. He and I stood in the back of the classroom chanting to each other, "I hope we don't traumatize them, I hope we don't traumatize them." Thankfully, we did not.

In 2008 the first teacher to actually go into space, Barbara Morgan, originally a backup for Christa McAuliffe and actually flew on Endeavour in 2007, addressed the National Education Association in Washington DC. I remember little of her speech, other than that it was inspiring.

Today I watched Atlantis launch on TV, the last ever Space Shuttle mission. My heart was in my throat and tears in my eyes, hoping that this would not be another disaster. Atlantis did launch successfully at 11:29am (EST). More than an hour later now, I'm not sure if it's already in orbit, or if it's still climbing.
40 years ago today the first man walked on the Moon.

Tomorrow I'm meeting the astronauts who serviced the Hubble Space Telescope for the last time on the STS-125 mission. [ profile] jmgold42 suggested as a question for them "Do you think we should go back to the Moon?" and I just may ask it (though I expect someone else will ask it). [ profile] blue102 suggested a question about how their perspective of Earth has changed, and how the Earth-bound of us can achieve that. I'm also considering "Do you think NASA should focus its energy and funding on manned or unmanned missions?" You can follow along with the NASA Tweetup event at the Twitter hashtag #NASATweetup.

If you could ask the STS-125 astronauts any question, what would it be?



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