A Moment Of Reckoning for Cassini

No_Weak_Heart writes "The NASA/ESA Cassini-Huygens probe has caught sight of Titan and is now returning images that 'rival anything scientists have seen before - and that includes images from the Hubble telescope.' See more detailed images at the mission homepage."

Comments

Too close to capture all of Saturn

[Azahar]

Now that Cassini is so close that it can't take a photo that includes all of Saturn I think it is a good time to start paying more attention to the photos coming back.

This is one probe that promises so much that I have decided to enjoy the anticipation and appreciate the photos as they return, slowly and beautifully.

Saturn is the dream planet after all, all those rings, all that mystery. I can't say that I would like to live in orbit around it though.

Little Green Men in our neighborhood

[Just Some Guy]

I know this is pretty off-topic, but given that we've never had a good look at the surface of some of these moons, is there any reason that they couldn't be inhabited be sentient creatures at the social equivalent of medieval Europe? Put another way, if there were a somewhat advanced society on Titan 1000 years ago, but one that hadn't ventured into space yet, how would they have been able to know that there was life on Earth at that time? We weren't broadcasting radio signals at that time, and hadn't made any large-scale modifications to the planet that would be visible from space (ie giant agricultural regions, cities at night).

I'm not a LGM kook - I have no expectation at all that we'd find any sort of life there. Still, is there any particular reason why we seem to be so sure of that?

Re:Little Green Men in our neighborhood

[tigersha]

Arthur C Clarke once wrote a nice little piece called "Apes or Angels" (Ok, the title may be wrong). Basically his point is that the universe is 10 billion years old, we have been here for 5 million years. That is a tiny drop in the lifetime of the universe. So if we hit alien species the chances that life on the planet would be exactly in the same range as our evolutionary scale is pretty remote because 1 million years back or forth yould not be much in the tiemscale that the universe operates in.

There is a much better chance that they would be either millions of years behind us (bacterial or so) or millions of years ahead. They would more probably or not be either Apes or Angels.

Btw, this is one argument to use to say why we have not found any aliens yet: No ways to find bacteria on a long range and perhaps if they are millions of years ahead they would be so strange to us that we would not now what to look for. All advanced technology looks like magic.

So the chances of finding a civilization close to here which is about 1000 year ahead or behind us is pretty much zilch purely from a statistical point of view.

Of course, the argument does not quite hold in the Solar System since all the bodies in it are about the same age per definition (they were formed at the same time). But then you could still be talking a million years give or take. No human-like organisms then.

Re:Little Green Men in our neighborhood

[Anonymous Coward]

"Of course, the argument does not quite hold in the Solar System since all the bodies in it are about the same age"

Since the conditions for humanoid life (just the right gravity, surface temperature that allows liquid water) exist nowhere else in the solar system, any intelligence we find would most likely be radically different from ours, even if life did arise on another body at roughly the same time as earth. But then, the dinosaurs were a widely varied species, wiped out suddenly; who's to say intelligent, saurian life couldn't have evolved here 60 million years ago under better circumstances? But for that accident, perhaps the current masters of the planet might be wearing monkey skin shoes ;)

I would criticize you on one small point, however: for the first few billion years of the universe's existence, life based on chemical reactions may not even have been possible because of high residual radiation (destroying complex, fragile molecules) and a lack of heavier elements. So, unless there's a hyper-intelligent form of hydrogen, the theoretical age of any life form is much shorter than the age of the universe; I'm not cosmologist enough to make a guess on the actual figure. But I still agree that another species being within 1 million years evolutionary time to us is fantastically improbable, as my dinosaur example illustrates. One little rock can make a big difference.

That never stopped anyone inventing anal-probe stories under hypnosis, though.

Cosmic reboot event?

[Kap'n Koflach]

Arthur C Clarke once wrote a nice little piece called "Apes or Angels" (Ok, the title may be wrong). Basically his point is that the universe is 10 billion years old, we have been here for 5 million years. That is a tiny drop in the lifetime of the universe. So if we hit alien species the chances that life on the planet would be exactly in the same range as our evolutionary scale is pretty remote because 1 million years back or forth yould not be much in the tiemscale that the universe operates in.
Although the general point is valid, it is only really true if the conditions that allow intelligent life have remained the same for the entire history of the Universe. E.g. older stars were formed when there were fewer of the heavy elements (carbon, silicon, take your pick) required to support life, so they probably aren't harbouring ancient transcendant civilisations.

To take another example from Science Fiction ('Space' by Stephen Baxter), what if something happens every few billion years that wipes out all life across an entire region of a galaxy - such as a very energetic Supernova or gamma ray burst. This might simultaneously destroy life in many nearby star-systems, starting them again from scratch. Although finding a local civ that is exactly the same age/level as your own would still be very unlikely, this sort of reboot would level the playing field a bit.