Dust Samples Returning to Earth at 28,860 mph

DjBenBen writes "After a 2.88 billion mile round-trip journey, NASA's Stardust mission is nearing Earth with comet and interstellar dust particles that could help provide answers about the origins of the solar system. Better yet, the velocity of the sample return capsule, as it enters the Earth's atmosphere at 28,860 mph, will be the fastest of any human-made object on record."

Comments

Re:and before anyone starts thinking relativisticl

[Tango42]

Because the speed of light in a vacuum is more important than just being the speed light travels in a vacuum. It's a fundamental speed that turns up in lots of places - it's the speed of light, the speed of gravity (probably, measurements place it within the margin of error), the "speed limit" of the universe, the square root of the constant of proportionality between mass and energy, and probably a few other things I can't remember/don't know.

The most important reason is the speed limit one - once you start getting close to c strange things start happening, which is interesting and worth thinking about. Once we get to the stage of having space probes travelling at relativistic speeds we can do all kinds of fun stuff, like sending them to other stars, etc.

Re:Interstellar?

[Vellmont]

The dust is interstellar because its origin is outside our solar system. That is it isn't bound gravitationally to our sun. Interstellar dust doesn't just sit around between stars, it moves relative to our solar system. IIRC it moves a lot faster than the local inter-planetary dust of our solar system (around 30 km/sec). Because of this there's interstellar dust blowing through our solar system all the time.

Re:Interstellar?

[Z0mb1eman]

I believe the "interstellar dust" the article refers to comes from comets (presumably from the tail?), which are generally interstellar... not sure why the article feels the need to mention "cometary and interstellar dust" in that case, but:

"Locked within the cometary particles is unique chemical and physical information that could be the record of the formation of the planets and the materials from which they were made," said Don Brownlee, Stardust principal investigator at the University of Washington, Seattle.