I *Really* Love Science!

[sheepdog 44]

The habitable zone around a star is based on water and the proteins that make up our body. If we were based on liquid methane like what is found on Titan, we would find the -290 degrees fahrenheit weather nice and balmy. It would be better to say that liquid is essential to life. Though all life we know of on earth uses our abundant liquid water.

If you look at the elements that make us up, all of them except trace elements are abundant in the Universe, and all of them are highly chemically reactive and can make complex molecules. Oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Carbon is reactive and can make more different molecules than all other elements combined. Water facilitates chemical reactions. All of those elements except calcium make up DNA which is needed to replicate. Oxygen in the air gives a fast metabolism. Many organic compounds can be naturally made in space. These components are so ideal, you'd have a hard time making life out of anything else.

One thing i wonder: They say life could have traveled to Earth from Mars on the ejected material from asteroid impacts. I wonder if there could be life on Europa that came from earth billions of years ago.

[NeilBlanchard]

One reason that ice being less dense than water is critical to life is that lakes and ponds would freeze from the bottom up, and that would much more likely to freeze solid. At the very least, if water behaved like every other material, life would have been completely different.

On the rotation/motion of our solar system around the Milky Way, I'm wondering if we can know what direction it is moving, in relation to the earth? The earth rotates west to east, and I *think* the earth orbits the sun in the "same" direction - but what direction does our solar system move?

[freebeard]

It's all relative.

For reasons that confound my dyslexia, the Eastern limb of the Sun on our left.

[NeilBlanchard]

http://www.youtube.com/watch?v=HdwOlk6HIVc

www.youtube.com/watch?v=r7BTqKeP6Ks

Richard Feynman: Fun to Imagine | Using physics to explain how the world works (1983)

NOVA (PBS) - Richard P. Feynman: The Last Journey of a Genius

[euromodder]

Originally Posted by niky

It's the water molecule's shape that determines its crystalline form... and makes solid H2O less densely packed than liquid H20... which also makes it lighter and capable of floating.

Don't recall why this is important to life...

It effectively insulates lakes, ponds and rivers with a layer of floating ice, keeping liquid water below it, even in arctic conditions - though the ice gets a tad thicker.

But ... expanding ice can also kill simple life forms or small animals through destruction of their cells, as they burst when they freeze.

[NeilBlanchard]

Ancient clues | Playlist | TED

David Christian: The history of our world in 18 minutes | Talk Video | TED

[NeilBlanchard]

Dan Barber: How I fell in love with a fish | Talk Video | TED

[NeilBlanchard]

You owe it to yourself to watch the new Cosmos series:

Cosmos: A SPACETIME ODYSSEY on FOX - Watch the "Some of the Things That Molecules Do" Episode

[Oceanic815]

Originally Posted by NeilBlanchard

Have you heard about rogue planets?

Living on Earth: Superman of Astrophysics



So, there is a fairly good chance that there is life on a large rogue planet that has a totally different reference point for time than those lifeforms like us who live on an orbiting planet - they have no day and night, no seasons, no years - but they do have an ever changing view of the stars.

If that doesn't expand your mind, I don't know what would!

I learned about rogue planets in the 90s by watching Star Trek DS9, right about when the Dominion War started.

[NeilBlanchard]

Rogue planets are mentioned in the (first?) episode of Cosmos, as well. There are billions of them, and the detail that Dr. Tyson mentions that was new to me is that while the core of the larger rogue planets is warm enough to support life, the surfaces would be frozen.