How cool is this?

Fourth of July fireworks can't compete with a bigger bang expected today more than 80 million miles above our heads.

The explosive adventure is a first for scientists: blowing up part of a comet in an attempt to learn what's inside. If all goes according to plan, NASA's Deep Impact spacecraft early this morning will have sent a cosmic projectile into comet Tempel 1, creating a shower of debris that could reveal clues about how comets form and the origins of our solar system.

The passing comet is like an unopened gift with secrets inside, says Joe Veverka, a Deep Impact team member and astronomer at Cornell University.

``If you look at the solar system, most of the sizable objects beyond Uranus are cometlike,'' he says. ``Most of them have been out there for a long time, and they haven't changed very much. If you're trying to get the building blocks of the solar system, you can't ignore comets.''

On Sunday, the spacecraft was programmed to release a copper plug 39 inches wide into the path of the comet. The impact is expected to release energy equivalent to nearly 5 tons of TNT and create a plume of pristine, primordial material from inside the comet.

The projectile needed little push. Deep Impact and the comet passed about 6 miles per second relative to each other.

``Approaching at high speeds is nice because you can use it to do your work for you,'' says Peter Thomas, a Deep Impact scientist, also with Cornell. ``We're just using the different speeds of two passing objects.''

Hitting the comet with a small object also makes more sense than trying to land a craft on the surface, Thomas says.

``To land, you have to slow the whole spacecraft, touch down gently and do a lot of things to drill into the comet,'' he says. ``With what we're doing, you just drop off this bowling ball and let it do its thing. You let velocity dig the hole.''

As Deep Impact passes the comet 300 miles away, its instruments will analyze the plume's chemical makeup and send data back to Earth.

``And we also have a camera on the projectile,'' Thomas says, ``which will work right up to impact.''

If the $333 million mission is successful, Deep Impact will be the first spacecraft to touch the surface of a comet. Last year, NASA's Stardust craft flew within 150 miles of Comet Wild 2 but didn't alter its surface.

``On previous missions, we've seen the outside of a comet, but we've never seen the inside,'' Veverka says. ``It has been argued that the chemical seeds of life on Earth were brought here by comets. We're not there yet, but one day hopefully we will know if you and I were descended from comets.''

Last week, the National Aeronautics and Space Administration released images taken by the Hubble Space Telescope, which show a new jet of dust streaming 1,400 miles from the comet's core. The images suggest that Tempel 1's icy nucleus - half the size of Manhattan - is dynamic and volatile.

Comets spend most of their lives in the far regions of the solar system, zipping around unchanged in a sort of deep freeze. Born billions of years ago, they hold the original ooze of an adolescent solar system, including frozen water.

Astronomers traditionally have studied comets as their orbits take them near the sun, when their surfaces heat up and expand in a cloud of reflective gas molecules called a coma. As this cloud extends outward, the solar wind sweeps it into a tail stretching millions of miles, often making it visible to the naked eye.

I heard about this on the news last night. Very neat! I'm interested to see what they find.

I bet they find some space bacteria that will be released and attack earth and make us all into undead brain eaters.

Go NASA.

2the9s said:

You'll be safe then.

jerseykrs said:

Watch this thread die, I should have asked people to post their pictures or list what song they are listening to


That says something about this site, doesn't it??

this is a great thread, jerseykrs. i've just been reading about the comet. i'm not sure why NASA had to smash it to get the information they want - they've done core samples elsewhere haven't they?

ah well.

jerseykrs said:

heh, heh.

XxAxX said:

I wasn't aware of any other sampling of the internals of the comet. I do know they have collected samples from the tails of various comets, either way, I'm very excited to see what they find.

jerseykrs said:

actually i think it's the explorers on mars that are doing drilling and core samples... i'm not sure that this same technology would work on a fast moving comet. i wonder if they'll attach a camera to the comet to track it from now on?

What always astonishes me with high velocity impacts, is how a projectile of circumference A can potentially produce a crater thousands+ times A in circumference. If I imagine a body the size of a football travelling at speed, I think probably because we don't deal on a day-to-day basis with projectiles travelling at such huge speeds, I'd imagine it to make a crater deeper than wide, and not too much wider than the football.

But, no. You'd get a crater many, many metres wide.

Awesome.
[Edited 7/4/05 7:43am]

TheFrog said:

It's like a drop of water and the ripple effect maybe Froggy?

Lleena said:

i just can't get my teeny head around it though!

i know it happens, and the maths makes perfect sense, but i'm not happy!

TheFrog said:

I know what you mean, you would expect the point of impact to be deeper rather than wider. Lets do an experiment, you drop one of your shoes from a great height into a field and take a pic and post it. Measure the circumference of the crater left by your shoe.

We will await your results!

Lleena said:

I will do this, as well.

Not sure how i'm going to get to a 'great height' over a field, but so help me, i'm on a mission, now!

TheFrog said:

How about you hire a plane and throw your shoe out into a field. Make a note of which field though.

yet another thread jacked....