The Puzzle of Martian Meteorites

Alien54 writes "Recent analysis of several new Martian meteorites is confounding planetary scientists. To put it simply, an awful lot of the Martian meteorites are way too young. According to this thi s story found at Space.com, standard theories predict that most meteorites from Mars should be billions of years old. However, almost half of the known rocks from mars are under 200 million years old. These results open up a Pandora's box of questions. The discussions should be interesting."

Comments

The Secret's Out

[dmccarty]

A lot of those craters are our testament to NASA's attempt at a Martian lander.
--

so certain are they?

[jafac]

The conclusion of the article says it all; that they need to send a lander to bring back samples from Mars as soon as possible.

IANAEG or CC (Exo-Geologist or Cosmo-Chemist):
I say this because until that happens, how can we be so sure that these rocks actually came from Mars? Yes, the chemistry is similar, to what we THINK Mars' chemistry is, based on our very limited (and no direct) observations, but if the planets, Mars included, formed by accretion of dust particles in space around the early Sun, then it stands to reason that maybe not ALL of the materials of similar Martian chemistry accreted to Mars. There could be any number of asteroids made of similar materials floating out there between Mars and Jupiter, and periodically colliding, getting melted, and sent Earthward. Sure, the stats may be against it, but I don't believe we really know all that much about the smaller residents of the asteroid belt.

I'm not saying that these rocks are not from Mars, but I'm saying that maybe it's time to entertain alternative theories as to these rocks origins, because the data doesn't jibe.

if it ain't broke, then fix it 'till it is!

Re:so certain are they?

[crumley]

Yes, the chemistry is similar, to what we THINK Mars' chemistry is, based on our very limited (and no direct) observations

Wrong, the Viking spacecraft made direct observations of the Martian atmosphere, and its these observations that are the basis of the claim that these meteorites are Martian in origin. The proof is really quite convincing. Take a look at some of the links available here.

To me it seems pretty clear that the meteorites are Martian, whether we know the geologic history of Mars that well seems to be a little bit more in doubt.

John Varley answer

[Nidhogg]

It took them 3 pages to say what John did in one sentence.

Best scientific answer to date: It beats the shit outta me.

The scientists are just in denial about the really obvious answer.

The inhabitants of Mars are firing these little rocks at us just to mess with our heads.

"Here Earth-scum! Take a gander at *foom* this one! Just quit bombing us with those damned probes!"

Argh. Waaayyyy too much coffee today....

Re:Unstable Isotopes

[MrScience]

I doubt it. There are many more isotopes, each with much greater half-lives than c14. Each is valid for a different range of years. For example, from http://www.talkorigins .org/faqs/faq-age-of-earth.html#howold:
The most direct means for calculating the Earth's age is a Pb/Pb isochron age, derived from samples of the Earth and meteorites. This involves measurement of three isotopes of lead (Pb-206, Pb-207, and either Pb-208 or Pb-204). A plot is constructed of Pb-206/Pb-204 versus Pb-207/Pb-204.

Bullseye!

[Verteiron]

Obviously the Martians were a race of giant creatures with immense strength and incredibly keen eyesight. Their primary sport was "Hit the Blue Dot", an odd pasttime which consisted of chucking rocks towards the earth. Any that managed to nail it, of course, got all the girls. Unfortunately, most of them were bad aims, as the Martian race obviously died out millions of years ago.

Re:Martian Source of Meteorites Inconclusive

[probejockey]

The reason that at least some of these rocks are thought to be from Mars is that bubbles in the the impact glass (i.e glass formed during the impact that ejected them from Mars) contain gasses whose isotopic rations could only be found in the Martian atmosphere. Others are believed to originate on Mars because the chemistry of the rocks indicate extensive geological processing that could have only occurred on a relative large (and wet) planet. Since these rocks have O isotope ratios that are unlike Earth's and it is really hard to get rocks up the gravity well from Venus, Mars is the only choice.

Interesting mind-game

[rho]

Had a conversation with my brother about something similar to this. The topic basically was, "The universe isn't as old as scientists believe". The posit: the universe (and all physical actions) are slowing down over time.

To explain: we know the age of X because of carbon dating. Carbon dating assumes that radioactive decay is a constant. What if, in the past, things happened much faster? Light travelled faster, radioactive isotopes decayed faster, etc. And as time went on, the physical properties assumed to be constant slowed down.

I dunno -- I know my VISA bill grows faster in the present than in the past, but VISA physics defies all rational thought. But, it's an interesting idea.

Re:Interesting mind-game

[(void*)]

No. There is no such universal scaling constant. It takes more than more one number to describe physics. Let me try to give you an idea of what I mean.

Suppose you doubled everything in size. You are two times large. Since everything doubles in size, it must mean that you can't tell the difference between now and before right? Wrong.

Since everything is doubled, the force of gravitation between say two planets would drop (increased distance). Nevermind, let's keep the force the same you say. So we have to increase the masses between any two objects (F = GMm/r^2 - remeber?). But having increased mass, do we now keep the forces between charges the same? If you do, then the charge to mass ratio of the elctrons and protons will change - this effect is measureable. Lots of physics - emission spectra of atoms and molecules would be different as a result. We might not even be around to observe this.

That was just playing around with distance. It does not work for time as well. Some combination of the two? Not even that.

In other words, if something was different in the past, we should be able to see that effect physcially as we look backword in time at the stars. The people who are selling this idea are not thinking broadly enough about the entirety of physical phenomena.

Something interesting to add to the recipe..

[Bowie J. Poag]

About a year ago I was on campus watching a lecture being given by one of the Profs from the Aerospace and Mechanical Engineering department here at the U... (U of A is a big school for space-sorta stuff) ..They were demonstrating a film prepared by the department about how the moon may have been formed. We've got big mongo array of Cray/SGI supers here on campus chugging on this sort of stuff around the clock, its kinda neet -- But anyway, the animation they prepared on these supercomputers shows a pretty big sized planitesimal smashing into the earth during its early years, and tearing a hunk of it off that eventually recollected and solidified, becoming our own moon. Everything in the simulation matched... They even got the moon resulting from the collision to have the same rotational period so one side is always facing the earth.

And now, why this is relevant:

There was some speculation that very early/primitive forms of life may have existed on Earth during the time this collision occured. The debris from the collision could very well have contaminated the rest of the solar system with life, including Mars. ALH84001 may just be the ancestor of a hunk of material that came off of earth, made it to mars, then got blown back here. Weird, eh? :)

By the way, 1998-2000 PROPAGANDA Image Archive CDs are now available. Click the "Enjoy!" link below...and enjoy. :)

Bowie J. Poag

Re:Dear Lord!

[rho]

I'd laugh at your ignorance, but you're not the only one who's gone off about carbon dating in this thread.

Well, I'm not really talking about carbon dating, but using it as an example for the whole of the idea. If it makes you feel better, replace "carbon dating" with "speed of light".

And you are allowed to laugh at my ignorance. In my family, I'm one of the ones holding the bottom of the intelligence ladder. I've got an electrical engineer father, a math teacher mother, two mechanical engineering uncles, a cousin with a 4.0 in Aerospace engineering and my brother who is finishing a computational engineering degree. I'm the creative one (euphamism for "well, at least he GOT a degree...").

I don't present it as gospel, but it is a philosophical argument that occurs in the scientific community (at least, the parts that I'm familiar with). It's called Uniformitarianism, or something similar. All things continue as they always have.

I find it sad, though, that you outright dismiss the idea. Everything I've ever read or heard from really smart people mentions that they don't believe that they know everything, or indeed a lot about anything. The quest for knowledge stops as soon as you believe that you know all there is to know.

I don't claim to know the answer. I don't even claim there is an answer. I just claim that I find it an interesting thing to talk and think about. It gives a different perspective on things, which may lead to a greater understanding of the problem, just as it may lead to a two hour wanking session. I make no guarantee or warranty.

Anyway, I appreciate the links. They've got good info, and I learned something new, which is cool. However, I will always keep in mind all of the things that science KNEW was true, until somebody discovered something else that discounted the earlier theory, which led to new things that science now KNEW was true... ad infinitum. They are working theories -- and good ones, I might add -- but only theories.