Orbiters Study Effect of Giant Comet-Caused Meteor Shower On Mars 48
An anonymous reader writes According to observations made by NASA and ESA orbiters, the extremely close flyby of comet C/2013 A1 Siding Spring to Mars was accompanied by a meteor shower larger than any seen on Earth. NASA said that dust from Comet Siding Spring vaporized high up in the Martian atmosphere, producing "an impressive meteor shower." An observer on Mars surface might have seen thousands of shooting stars per hour. "This historic event allowed us to observe the details of this fast-moving Oort Cloud comet in a way never before possible using our existing Mars missions," Jim Green, director of NASA's Planetary Science Division at the agency's Headquarters in Washington, said in the statement.
Effects on Martian atmosphere (Score:5, Interesting)
Re:Effects on Martian atmosphere (Score:5, Informative)
MAVEN detected large spectrometry spikes for several metallic elements, and several non-metallic ones as well, which persisted for hours after the comet passed by.
Hang on, I will dig up a source.
http://www.universetoday.com/1... [universetoday.com]
Bam. There you go.
Re:Effects on Martian atmosphere (Score:4, Interesting)
Not with an 80 million year transit period it isn't.
A series of radiative heaters stuck to the surface with a computer control system would do the trick. (assuming some long lived power source, like a suitably large RTG)
The real trick then is getting probes into the oort cloud and attaching them to the nearest candidate objects at a human-sensible timetable. Without FTL of some sort, or at the very least, a significant improvement in thruster technology, this is a non-starter.
kuiper belt objects on the other hand, could theoretically be harvested within human timetables, and asteroid belt objects most certainly could.
Stone type asteroids contain a significant amount of bound elemental hydrogen and oxygen. That makes them attractive candidates.
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Re:Effects on Martian atmosphere (Score:5, Interesting)
Enlighten me-- what feature of your professed "reality" did I miss?
Oort cloud objects are so far away, that it takes them literally millions of years for them to reach our part of the solar system after they get nudged from their orbits by passing stars perturbing their orbits.
Rather than rely on stellar interaction, a mission to purposefully send robot drones into the oort cloud is theoretically possible, but as I pointed out, would require either FTL or a radical improvement in thrust technology to accomplish on human timetables. It took 70 years for voyager to reach the heliopause, AFTER it was gravitationally accellerated by several gas giants. The voyager probe was pretty small too, in comparison to what would need to be sent to the oort cloud to commence a mission of the magnitude the OP suggests. Getting something that heavy out that far before it's mission creators die of old age is a pretty significant bump. That's why I covered that bit by saying it would require, at the very least, a radical improvement in thruster technology.
Once out there though, all it would take is slow, but constant thrust on an object to dislodge its orbit. There would be considerable time for these objects to pick up momentum from their inward plunge. Again, a radiative heater aimed at the surface of the comet at strategic points, controlled by a computer guidance system, would allow for the comet to be steered into the appropriate entry window for mars collision.
It would just take a very, very, very long time. Last I checked, "Very long time" != "Can't be done".
Then we come to the latter point I made-- objects in the asteroid belt between mars and jupiter. Objects in this area are much easier to get to, and could realistically be sent on collision courses with mars regularly with a fleet of automated vehicles. Ion thrusters are more than adequate for this latter kind of planetary engineering. Objects in the asteroid belt range from dust particles to things the size of mountains, to those the size of small moons. You dont need nor want the collossally huge ones. You dont want to destroy the target planet with a massive collision, after all. Sending objects the size of dump trucks or so to mars using controlled, vectored ion engine thrust over long timetables of several years is perfectly plausible.
Since I am telling you how it COULD be done, and you are insisting that it cannot, "because orbital mechanics", the onus of proof is on you.
No, calling me a "Space nutter" or other ad-hominem does not absolve you of this obligation.
Re:Effects on Martian atmosphere (Score:4, Interesting)
*Yawn*
Oh, so things like this [wikipedia.org] simply can't ever work huh?
Nevermind that it is fully mathematically sound, and the only reason why it was never used was because of anti-nuke hysteria. No no-- your "reality" says things like this are simply not possible! (Since you seem to be so thick, I am using the scare quotes to point out that what you consider to be reality is a fiction of your own manufacture, which does not in any way hold with what is actually possible.)
You mean, like this post I made last year? [slashdot.org]
Synthetic biology is closer than you realize sir.
Aramid plastic has a thermal decomposition temperature of 500c, which also happens to be the mean surface temperature of venus.
Aramid plastic [wikipedia.org]
Venusian climate and atmospheric composition [wikipedia.org]
There is a sufficiently high concentration of suitable sulfur compounds in the upper venusian atmosphere, where it is a nice balmly 70 degrees Fahrenheit, for sulfur-cycle microbes to live perfectly happy, carefree lives-- shitting out aramid plastic non-stop should they be engineered to do so. Given that that the feedstock used to produce aramid plastic is an amine group and a carboxyl-halide group, this is a perfectly reasonable material to biosynthesize. (Biogenic amines [wikipedia.org] are a staple of most terrestrial lifeforms in fact, and there is sufficient carbon dioxide and hard sulfuric acid vapor in the venusian atmosphere to allow sulfur cycle energy production [wikipedia.org], with carboxylic acid biproducts of celluar activity. Combined, it is not hard at all to imagine aramid being biologically synthesized, and falling to the venusian surface as the microbes die. This would result in accretion of a carbon-rich material that is thermo-stable at venus's existing surface temperature, which would puncture the greenouse effect of the planet.)
But of course, I TOTALLY never made posts about that in the past-- No sir-- that would fly in the face of your "reality", where "Space nutters" dont have interesting proposals about venus at all!
We couldnt let the actual reality that this is not true intrude at all. No sir.
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For the combined costs of 1 sandra bullock movie, and the tuition of 5 college students, what I proposed can be done.
We have biotech scientists working on making artificial ribisomes, artificial cell walls, and fully synthetic genomes *RIGHT NOW*.
See your problem?
One of us is discounting the current reality, in favor of a preconceived world view. The other is not.
Designer microbes aren't nearly as expensive as you believe them to be, and the costs of sending a vehicle capable of interplanetary flight is les
Re:Effects on Martian atmosphere (Score:5, Interesting)
The indian mars orbiter, a vehicle with a lander module, and designed for interplanetary flight, cost less to manufacture and launch than the sandra bullock movie Gravity.
Source
http://money.cnn.com/2014/09/2... [cnn.com]
So, there's the cost of a suitable vehicle. About 74 million dollars.
Then we have the designer microbe end. Most designer microbes are intended for biofuel production, using fully synthetic biological pathways, designed by humans.
http://www.hindawi.com/journal... [hindawi.com]
Other sources of interest are the biodegredation of toxic agents:
http://www.nature.com/nchembio... [nature.com]
And of course, Plastics.
http://garj.org/garjm/pdf/2013... [garj.org]
Feel free to order some of those researcher's samples!
Perhaps you would want some that are sporting a fully 100% human created genome?
http://www.jcvi.org/cms/press/... [jcvi.org]
Microbes are tenacious things. Once cultured in the lab, and loaded into a delivery system, sending them to venus would cost about 80 million dollars.
Cost of R&D of modifying a suitable sulfur cycle microbe for venusian atmospheric conditions would cost around 100 to 200 million.
So, for around the 300 million dollar mark, we could be initiating the end of the hellish environment on venus-- OR-- we could pay for a few military airplanes.
You are a delusional moron.
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Don't worry. The rest of reality is not beholden to your views of it.
The real world will just move on without you. You can be as obstinate and stupid about it as you like.
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10 years? Probably not, no.
SpaceX has only been in BUSINESS for 12! While it has made extraordinary leaps in progress, it has been borrowing very heavily from already proven rocket technologies.
In 10 years, I would expect spaceX and pals to be at the level of service required to successfully ferry people to and from the ISS with reusable and inexpensive modules as a regular "ho hum" occurrence.
Wouldnt be for another 30 or so by my estimations that we would have significant interest in lunar based manufactur
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Such pearls of wisdom, from a guy who cant look past his own lifetime to find value in doing something.
Having a living biosphere on venus, where currently there is none, would be one hell of an accomplishment. It does not matter if the resulting biosphere is incapable of supporting human life.
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All life on earth, including you, came from single celled microbial life.
A biosphere in its infancy on another world, ripe for scientific analysis as it evolves (Which it would, VERY quickly. Microbes evolve terrifyingly fast!) would be a boon in ways your philosophy cannot even begin to comprehend.
As for "The right"-- What right do you have, as a human, to justify mass extinctions of far more complex lifeforms and whole biospheres, just so you can have a flatscreen TV?
Be careful there kettle. It's not wise
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The cost of said odyssey is around 300 million dollars, and is a one-time cost, with dividends for your leisure society. Specifically, biologically synthesized aramid fibers on the cheap would enable the construction of better buildings for humans to live in, better clothing for humans to wear in hazardous situations, and possible medical applications as suture material. It's something you can get almost for free, when you consider that the scientific trajectory of your leisure society objective also encomp
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The amount of energy it would take to launch from Earth (accelerate), rendezvous with an object (accelerate again), and provide enough energy to accelerate that object into a different orbit is more than we know how to engineer. If you really want a few gallons of water on Mars, send a cargo ship. Forget about steering an object with hand waving technologies like ion engines or heaters.
Here's a real world calculation [lbl.gov] for you:
CONCLUSION: A meteor has 100 times as much energy per gram as does TNT!
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Issues with your calculation:
1) it's cherry picked. The premise stated by the calculation is that the object is in or near earth's orbital vicinity. To avoid being drawn into the sun, it will require a considerable inertial energy statistic. Items in the very deep solar system? Not so much, since gravity falls off with the inverse cube of distance between the center of mass of the two gravitating bodies.
That means that the object the OP referenced, an oort cloud object, need not have the orbital energy tha
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Using kepler's third law, an object weighing 1 gram, at a distance of 100,000 AU (the oort cloud), orbiting a star with 1 solar mass, will have an orbital period of 316174 CENTURIES. (Or, 9.97786e+14 seconds)
We then need to know the total distance of the orbit, in order to determine the orbital velocity of this object.
Best current estimates for the location of the oort cloud is between 5,000 AU and 100,000 AU. We can use these as the semiminor and semimajor axes of the orbital elipse. This gives us a circu
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But the question is how much energy does it take to accelerate that object to Mars? (and you can't ignore the fact that you need to get out there with some kind of thruster and rendezvous with it, because that's what you suggest doing). You could use a gravitational slingshot to get there, but then you need to accelerate into that object's orbit. Voyager 1 is traveling roughly 17,000 meters per second, you would need to stop that velocity somehow.
Or take your simpler problem, a roughly one meter diameter r
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To accellerate it toward mars? Not much-- you just need to slow it down a little, so that solar gravity can better work on it, causing it to spiral into the gravity well. The total transit distance will be very large, so a small thrust applied over the duration will be sufficient to control its descent into the well. (The energy exerted against the object does not "Go away"-- it is conserved in the momentum of the object.)
Getting there is the real problem. That's why I said it would require a radical depar
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? Not so much, since gravity falls off with the inverse cube of distance between the center of mass of the two gravitating bodies.
By the way, that statement displays a fundamental lack of understanding of orbital mechanics. Read up on a little something called "angular momentum"
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I know what angular momentum is.
In this case, the value of thrust applied does not change with the difference in the size of the circumference of the rotating body. While the same thrust applied at one circumference may not be suitable to cause significant delta of the object, it may well be at a different circumference, because the same energy is conserved over a longer period. Several years of constant low level thrust would be functionally equal to moments of very high thrust, when the full system energy
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It's all a matter of priorities, and most of these fools feel as though theirs are the only priorities that matter. India's mission to Mars cost less than the wedding of the daughter of one of its industrialists a couple of years ago. The wealth of the Walton heirs alone could come close to funding a sustainable Lunar colony,
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Um, actually the Voyager probes were launched in the late 70s, so it's been less than 40 years.
A return trip would certainly take a while longer due to slowing down, sample gathering, and then managing to accelerate back home. But this wouldn't be the first time [wikipedia.org] that projects have begun that are longer than a typical human lifespan.
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Leverage the butterfly effect. You use a small object to gradually change the orbit of a progressively bigger one on up to a big comet. Sure, it takes a while, but cheaper. Tradeoffs.
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You use a small object to gradually change the orbit of a progressively bigger one on up to a big comet
Butterfly Effect? Does that somehow trump Newton's Laws of Motion? Because that's what you are suggesting.
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I want pics. (Score:2)
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Likely the evidence comes from radio observation of the echoes from the impacts i nthe upper atmosphere. That's a popular rate measure on Earth too, because it doesn't depend on (absence of) sunlight, cloud cover, etc.
Larger than any on Earth? (Score:2)
I am told that the Leonids in 1833 estimated between 24,000 and 100,000 meteors per hour.
Maybe it is Fallout from Galaxy Quest? (Score:1)
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