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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."
Thats like a speeding bullet stuck in the back end of a bat out of hell
Signed Smegger.
Funtage Factor: Purple
At such velocity,I sure hope the capsule won't add to the dust.
"Life," said Marvin dolefully, "loathe it or ignore it, you can't like it."
28,860 mph is just over 8 miles per second. When compared to lights speed of 186,000 miles per second in a vacume, it isn't much to write home about. Granted it's still fast, and I don't really think I want it hitting my appartment, or even your mom's house...
-Rusty
You never know...
acc to http://galileo.jpl.nasa.gov/mission/journey-probe. cfm, the probe released by galileo hit jupiter's atmosphere at about 4 times that.
Yeah, but they're talking about re-entering *Earth's* atmosphere. *That's* the record it's breaking.
maybe it'll hit my mother-in-law's house
Beer! It's what's for breakfast!
After all, an organization must have a flawless track record before they're allowed to accelerate a projectile at 28,860 miles per hour towards the earth.
vacume? wtf? can't we all agree to just say in vacuo and man didn't create and accelerate light so what are you on about?
I fail to understand what is the point in comparing natural radiation speed in a vacuum (don't declinate, if you are not speaking Latin) with artificial physical object speed in the atmosphere.
Nuffsaid
________
Don't know about his cat, but Schroedinger is definitely dead.
Let's hope for a smoother reentry than that of the Genesis probe
Nuffsaid
________
Don't know about his cat, but Schroedinger is definitely dead.
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.
What's the definition of interstellar dust? Wouldn't the probe have to leave the solar system to get it, which it obviously didn't?
I would have thought interstellar dust was what's beyond the heliopause, anything inside is interplanetary at best.
Now instead of just smashing into the Utah desert at a mere 193 mph like the Genesis mission, they can really drive that sucker into the dirt! I just hope NASA has some staff in China to recover the capsule from whomever's back yard this thing pops up in.
What's expected accuracy? What is the possibility to miss expected landing site and hit some populated area?
but before anything when is a f.....g blog a source of accurate information ??
... it escapes it.
The "something wrong" is that a mobile animated with a speed superior to 24.000 km/h cannot enter the terrestrial gravity
That's it.
well the wright brothers didn't fly anywhere near as fast as light in vacuo, i guess we shouldn't record any of their work down in history, eh?
...with a speed superior to 24.000 km/h cannot enter the terrestrial gravity...
Boy, you just fell off the wrong tree and hit every branch on the way down.
Why, o why must the sky fall when I've learned to fly?
... welcome our new Supersonic Dust Particle Overlords.
Not here. Not nearly. Moreover, who cares about relativistic effects on interstellar probes? The travel may seem to be short by the probe's point of view, but it will still take years for us on Earth. And it's not difficult to build a robot with infinite patience.
Nuffsaid
________
Don't know about his cat, but Schroedinger is definitely dead.
The fact that it's relativistic isn't important for a probe, no, it's just the fact that it's very fast that's important and relativistic speeds are the fasted you can get.
To be firing objects back at earth? I don't care about them sending them out to space or landing on other planets, but I feel like I have a target on my back when they start returning them back to earth at such velocities.
I haven't thought of anything clever to put here, but then again most of you haven't either.
Someone call the WILDFIRE team and start getting them decontaminated...
GCHQ Quantum Insert installed. If only our tongues were made of glass, how much more careful we would be when we speak
Can you say "Aerobraking"? And, ignoring that, if said 'mobile' impacts the planet i seriously doubt it will escape.
"You will begin to touch heaven, Jonathan, in the moment that you touch perfect speed. And that isn't flying a thousand miles an hour, or a million, or flying at the speed of light. Because any number is a limit, and perfection doesn't have limits. Perfect speed, my son, is being there." - Chiang (Jonathan Livingston Seagull)
"I'm not impatient. I just hate waiting." - My Dad
Boy, you just fell off the wrong tree and hit every branch on the way down.
No, he's right if you take it literally. It will be travelling well above escape velocity. Obviously it's going to slow down somehow.
"...always new atoms but always doing the same dance, remembering what the dance was yesterday." -Richard Feynman
Wildfire is right. Recall the paranoia that confined the first moon astronauts to quarrantine in Airstream trailers. Now we're grabbing who knows what and trusting some automated system to seal it up in space, then smashing it into our atmosphere and hoping it doesn't scatter stuff to the 4 winds. Any public discourse prior to doing this? No, NASA scientists know better. Andromeda Strain, based on the book by Michael Crichton of Jurassic Park fame, is required viewing here.
-mz
...the bodies of the recently deceased returning to life and attacking and devouring the living, at least you know why.
If my grammar and spelling are off, I am [distracted/tired/careless] (take your pick)
Your physics teacher needs to be fired/lynched/shot (depending on local laws)
First of all, your units are wrong. Escape velocity is around 25,000 MILES per hour.
Second, if the object is actually headed *towards* earth, it's own trajectory will preclude it from "escaping". Do you think anything traveling faster than escape velocity will simply quantum-tunnel through the earth?
Third, lots of meteors enter the earth's atmosphere every day with velocities on the order of, or exceeding, the "escape velocity" of earth. Yet, somehow they magically manage to burn up in the atmosphere and/or strike the earth anyway. Wow. Do ya think that maybe, just maybe, the probe might use a similar technique/trajectory to return to earth?
Ignorance can be cured. Stupidity is permanent. I'm not sure what camp you fall into yet.
Actually, yvesdandoy used the right units (SI), he just got the wrong number from a table with the wrong units. ;-) Let's face it: only 5% of the population on Earth still has a problem with the metric system. It seems ignorance cannot be cured.
/. refers to "mph". I see too often that students use such nonsense. Of course, they have no concept for units. If someone had told them at school to write "km/h" instead, then the students may realize one day that this means distance divided by time. They would prefer a system where each physical quantity requires only one (1) unit or a product of other units (one unit for time, only one for distance, one for mass etc.). They would know that G, M, k, m, etc. are only factors with a radix of 10. They would find that formulas and units used in formulas have to match on both sides of an equation. They would be able to verify this relationship for every equation and benefit from this simple test. Students would appreciate the concept of having the same radix for units and our number system (only 10 - not 6, 12, 14 and 16 combined). I see too often kids leaving high school with absolutely no concept for units. No offense, but something goes very wrong. It is not just in Kansas.
/. "mph" article will show up shortly.
The article posted here at
I am sure the next
http://www.metric4us.com/
BTW the cross section of neutrinos interacting with hadrons and leptons is so small that most neutrinos penetrate earth without interaction. Our probes are just not made out of neutrinos.
Well, I stand by my assertion that yvesdandoy used the wrong units...as he clearly pulled a number out of some reference and blindly attached a set of units to the end of it...clearly demonstrating a lack of knowledge of the physical system he/she was trying to comment on...and therefore using the wrong units attached to a (basically) correct number due to this lack of knowledge. ToMAYto, ToMAWto :p In any case...yvesdandoy's physics teacher should indeed be fired/shot/lynched as I earlier suggested.
And yes, I'm aware of the neutrino situation...and I appreciate the subtle jab at my rhetorical question I asked yvesdandoy. And as you pointed out, our probe isn't made of neutrinos...and thus would be stopped shortly after making contact with the surface of the earth, regardless of fraction of escape velocity it was traveling.
And by the way, "mph" is a perfectly acceptable term to use in measurements. Miles Per Hour describes the same mathematical quantities as miles/h. Likewise, Kilometers Per Hour (sometimes written kph) describes the same quantity as km/h. At least, it does to those who understand English beyond a 3rd grade level (becoming a rariety in our education system, I'll grant you). If you want to outlaw mph, you should also outlaw the legal terms Per Annum, Percent, and any number of such terms that describe quantitative relationships in some form other than what can be plugged directly into a unit analysis form of problem solving without a little interpretation. Wow...nice run-on sentence, huh? In any case, such nomenclature is widespread throughout most industries...so perhaps your students would be better served if you made them convert between various nomenclatures as well as unit systems, rather than pretending that only the "proper" nomenclature with SI units was the one-and-only way to describe things in the world.
As an engineer...I agree that the world would be a better place if we all used the same set of units across the world...SI or otherwise. I get tired of having to convert from one to the other...not to mention the potential for grievous errors from faulty conversions (smoking crater in Mars ring a bell to anyone? LOL). But also as an engineer, I recognize the reality of how the world works, and thus the necessity of being able to function in any/all unit systems and nomenclatures. It certainly beats hiding behind some utopian idea of measurements and nomenclature born in academia at the expense of being able to deal with anything that might be thrown your way. My 2 cents (sorry, I mean my 0.02 dollars).
That's kind of like the old saying that according to aerodynamic theory, bumblebees can't fly. If that's your theory, it's a bad one. Obviously if the object is going 24k km/h directly AT the earth it's going to "enter earths gravity". The Earth slows things down quite nicely when things impact it. No braking or even atmosphere required.
AccountKiller
BTW the cross section of neutrinos interacting with hadrons and leptons is so small that most neutrinos penetrate earth without interaction. Our probes are just not made out of neutrinos.
And if the probe were made out of neutrinos you would have a point. Of course it's not, so I'm sorry to say you just sound like a smartass trying to throw your knowledge around.
AccountKiller
In space, no one can hear you sneezing because of the dust.
Now before I get modded down, I be to remind whoever might read this that what I am saying is FACT. - bogaboga