Ion Rocket to Map Moon with X-Rays

jralls writes "The Guardian is reporting that a European ion-rocket has taken the last year to reach the moon and is about to enter lunar orbit. Once it slows and gets into a very low orbit, it will probe the surface with x-rays in an effort to solve the long standing puzzle of the moon's origin."

A year to reach the moon?

[ravenspear]

I keep hearing that Ion propulsion is faster than what we currently use. What's with the incredibly slow travel time?

Re:This begs the question:

[marsonist]

... the beagle2 is laughing at your post all the way from mars

In all seriousness it's nice to see some other serious large-scale attempts being made by countries other than the US and Russia. As with all things scientific, the more head working together the more we all learn.

Re:Visibile from Earth?

[wertarbyte]

If we used some sort of higher powered rocket to generate the velocity, I wonder if ion rockets could hold that velocity for a long time.

Since we are using this space, I wonder what we would need the ion rocket for to hold that velocity. In space, there is not much that could slow you down.

From the article -- galactic bowling physics?

[jdkane]

Smart's map should provide that data and show if scientists are right in believing that the Moon coalesced from a vast ring of debris generated when an ancient planet the size of Mars destroyed itself after crashing into Earth. Understanding the origins of the Moon will therefore give insights into the nature of our planet.

Doesn't this mean earth should have some huge dent in it, and not be so round? Look at the sizes of Mars and Earth [nasa.gov]. Are you surprised earth is still here after a crash of that magnitude? I am. Maybe earth was a lot bigger before a Mars-like planet destroyed itself crashing into earth, but then I go back to my question about the roundness of the earth.

Maybe someone more knowledgeable wants to talk about that. The article doesn't go into any great detail on that, which causes a lot of questions to be raised.

Keep in mind....

[WindBourne]

that it is not the whole moon. There are areas that light, and x-rays do not reach. Sadly, that is the most inteesting as it may contain ice.

Biq == Round

[DumbSwede]

Beyond a certain size, gravity pulls things into a spherical shape. The immense pressure makes the insides molten and irregular structures eventually sink down in. Mars has Mons Olympus, the tallest volcano in the solar system, this is because Mars is smaller and has less gravity than Earth. The larger the planet the more regular it has to be. Asteroids can be highly irregular because they haven't the size and gravity to collapse them into spheres.

The mountains on Earth may appear huge to us insects on the surface, but from a distance the earth appears as smooth as a billiard ball.

Ironically this event was so big, that unlike latter smaller hits, all evidence in the way of dents will be gone as the entire globe virtually liquefied and coalesced again. Though I wouldn't rule out some exotic mass distributions that might lend evidence of it.

Re:Accreted Rings

[cjameshuff]

It's really freaking big. Mercury and Venus don't have any moons, and the moons of Mars appear to be captured asteroids...relatively tiny rocks not big enough to form themselves into spheres. The Earth-Moon system is nearly a double planet. Of the inner planets, Earth is the only one with a decent moon...and it's a monster compared to the planet.

In any case, the planets you see now are just the ones that stayed in the system. Material didn't just cleanly accrete directly into the existing bodies. Most of the objects formed were kicked out of the system by interactions with other bodies, or were absorbed into other objects or the Sun itself. What you see is the final result of a great many collisions and near-miss interactions. (And the present orbits aren't truly stable, just stable enough not to worry about. I think the lifetime of the present orbits of the planets is greater than that of the sun itself. Maybe a little less for the Moon.)

The rings of the gas giants are likely far younger than the planets themselves, they are almost certainly not leftover material from the accretion. And they do have moons, lots of them...each giant has dozens, while the entire inner system has 3. However, even taken together, the moons and rings of each giant aren't much compared to the planet itself.