Shedding light on the moon

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Poobar
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Shedding light on the moon

Postby Poobar » Fri Apr 17, 2009 9:39 am UTC

I'm doing a PhD where I'm supposed to be making maps of the moon. The trouble is, the instrument I'm using relies on X-ray fluorescence from the lunar surface, and the Sun hasn't started up again into it's next solar cycle. There are pretty much no x-rays coming from the Sun. Therefore there are no x-rays hitting the moon. The lunar surface isn't fluorescing, and the multi-million pound instrument I'm meant to be getting data from is so much space-debris. My dreams of being able to call myself a lunar cartographer are hanging by a thread.

I need help. How can I illuminate the moon with x-rays? Solutions need to be reasonably priced, and hopefully not provoke all out nuclear war.

Nuclear War?

The best solution we in the postgrad office can think of is setting off a chain of nuclear explosions in space, so that the x-ray flashes continually hit the moon. As Saint Obama has just announced an end to the nuclear age, there's a lot of warheads around going spare! I've been searching around of detailed info on the strength and duration of the x-ray flash from nuclear detonations (MI5 probably have a file on me already...) but can't find it anywhere.

Pros: Might work. Cons: Unproven. Possible slight radiation side effects. High cost of launchers. Possible annihilation due to all-out nuclear war.

Any thoughts? Any other suggestions?

Mr_Rose
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Re: Shedding light on the moon

Postby Mr_Rose » Fri Apr 17, 2009 10:39 am UTC

Have you considered launching a Xaser satellite, possibly into Lunar orbit?
I bet you could get even more interesting images with polarised coherent radiation than with the somewhat random nature of the X-rays dear old Sol puts out. Especially if you could get two of them up and contrast the polarisations illuminating the same spot - an acquaintance of mine does this with visible light and biological samples to get sub-wavelength resolutions (I think; it's been a while since we discussed it last)...
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idobox
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Re: Shedding light on the moon

Postby idobox » Sun Apr 19, 2009 1:02 am UTC

Does a Xaser need to be space-bound?
I don't know the absorption spectrum of the atmosphere in X-ray, but if it's low, it should be possible to build a powerful and very directive source of X-ray on Earth, and aim for the moon.
An other possibility could be to put a particle canon in orbit and shoot at the moon. Neutral relativistic particles hitting the tenuous lunar atmosphere, or the surface, should emit x-rays, and the beam should remain much more collimated.

Anyway, lighting up the moon with an intensity comparable to the sun is gonna be difficult.
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Re: Shedding light on the moon

Postby Soralin » Sun Apr 19, 2009 11:26 am UTC

Borrow the http://en.wikipedia.org/wiki/European_x ... tron_laser And point it at the moon where you want to look. :)

Poobar
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Re: Shedding light on the moon

Postby Poobar » Wed Apr 22, 2009 10:59 am UTC

Unfortunatly the Earth's atmosphere is pretty much opaque to x-rays:

Image

I think it's the O2and Ozone in the atmosphere that blocks X-rays, but I could be wrong.

A spaced based Xaser could work, but it'd have to be pretty powerful to illuminate the lunar surface from orbit, and therefore require pretty heavy cooling systems- pushing the price way up. To my knowledge the only Xasers sent into space for planetary spectrography have been mounted on landers/rovers; they don't have to be very powerful if they're a few cm away! I don't doubt we could get some fluroescence from even a relativly cheap orbital Xaser, but I really need it as bright as possible- think M and X solar flares, massivly energetic particles needed- otherwise heavier elements such as Iron and Titanium won't show up. So we'll call Giant Multimillion Pound Orbital Xasers plan B, good but not perfect.

By the way, no-one has yet suggested we restart the Solar Cylce as in Sunshine: http://www.imdb.com/title/tt0448134/. For this, I thank you.

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SpitValve
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Re: Shedding light on the moon

Postby SpitValve » Wed Apr 22, 2009 7:17 pm UTC

Out of interest - what telescope are you using? Chanda/XMM/Suzaku or some combination?

Comic JK
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Re: Shedding light on the moon

Postby Comic JK » Wed Apr 22, 2009 8:35 pm UTC

Poobar wrote:A spaced based Xaser could work, but it'd have to be pretty powerful to illuminate the lunar surface from orbit...

You only need to illuminate a few square meters at a time, no? Assuming you can point the telescope wherever you want. That's not such a huge x-ray beam. Much, much cheaper than atom bombs, and more uniform x-rays as well.
Poobar wrote:...and therefore require pretty heavy cooling systems

Space, at least in the shade, is very cold.
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Re: Shedding light on the moon

Postby JWalker » Wed Apr 22, 2009 8:48 pm UTC

Comic JK wrote:
Poobar wrote:
Poobar wrote:...and therefore require pretty heavy cooling systems

Space, at least in the shade, is very cold.


Space is cold, but the only way to transfer heat in space is through radiation, which isn't very effective. Satellites do require some pretty sophisticated cooling systems, and an x-ray laser is going to run way hotter that most satellites.

To this OP, sadly I doubt this is going to be possible with a grad students resources.

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Kizyr
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Re: Shedding light on the moon

Postby Kizyr » Wed Apr 22, 2009 10:37 pm UTC

Poobar wrote:The best solution we in the postgrad office can think of is setting off a chain of nuclear explosions in space, so that the x-ray flashes continually hit the moon. As Saint Obama has just announced an end to the nuclear age, there's a lot of warheads around going spare! I've been searching around of detailed info on the strength and duration of the x-ray flash from nuclear detonations (MI5 probably have a file on me already...) but can't find it anywhere.

Pros: Might work. Cons: Unproven. Possible slight radiation side effects. High cost of launchers. Possible annihilation due to all-out nuclear war.

As far as I know, we're still under the Partial Test Ban Treaty prohibiting nuclear weapons tests in outer space. So, besides the possible side effects of radiation, high cost, and nuclear apocalypse, it's also prohibited under our current international agreements.

Not being an astronomer, I'm afraid I can't offer much help. Though I'm interested to see what folks come up with. KF
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Re: Shedding light on the moon

Postby Carnildo » Thu Apr 23, 2009 6:26 am UTC

Comic JK wrote:
Poobar wrote:...and therefore require pretty heavy cooling systems

Space, at least in the shade, is very cold.

Cold, yes, but it's also an outstanding insulator. Most heavy-duty insulated containers have a vacuum layer somewhere in them because it completely blocks heat transfer by conduction and convection, leaving only radiation.

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SpitValve
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Re: Shedding light on the moon

Postby SpitValve » Thu Apr 23, 2009 12:32 pm UTC

In fact, the infrared satellite Spitzer is just about to run out of liquid helium coolant - without that, it's going to be too hot to use most of its instruments properly...

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Velifer
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Re: Shedding light on the moon

Postby Velifer » Thu Apr 23, 2009 1:17 pm UTC

Get some astronauts to peel lots of Scotch tape apart while on a spacewalk?
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mollusk
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Re: Shedding light on the moon

Postby mollusk » Thu Apr 23, 2009 4:42 pm UTC

Poobar wrote:Unfortunatly the Earth's atmosphere is pretty much opaque to x-rays:


I'm inclined to put this fact in the "Fortunate" category.
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Re: Shedding light on the moon

Postby evilbeanfiend » Thu Apr 23, 2009 8:06 pm UTC

idobox wrote:Does a Xaser need to be space-bound?
I don't know the absorption spectrum of the atmosphere in X-ray, but if it's low, it should be possible to build a powerful and very directive ...


the absorption has already been covered, but isn't directing x-rays actually pretty hard? x-ray telescopes all use coded masks if i'm not mistaken (so basically they are slightly fancy pin hole cameras) and medical people taking x-ray images tend to scarper behind big lead screens and such like.
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Re: Shedding light on the moon

Postby Tass » Fri Apr 24, 2009 1:03 pm UTC

Velifer wrote:Get some astronauts to peel lots of Scotch tape apart while on a spacewalk?


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Re: Shedding light on the moon

Postby Yakk » Fri Apr 24, 2009 2:44 pm UTC

I thought there was a trick where you could use nuclear bombs to trigger a gamma-ray laser.

It might be more efficient and directed than just setting off nukes in orbit.
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Anubis
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Re: Shedding light on the moon

Postby Anubis » Sat Apr 25, 2009 11:17 am UTC

Is this purely hypothetical, or are you seriously considering trying to illuminate the moon with x-rays?

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EvilDuckie
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Re: Shedding light on the moon

Postby EvilDuckie » Sat Apr 25, 2009 12:06 pm UTC

This may be a very obvious question, but have you checked whether there is data available already? NASA is offering a load of data online, albeit somewhat tricky to find, that may just have what you're looking for. There may still be a career as lunar cartographer in your future :wink:
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Poobar
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Re: Shedding light on the moon

Postby Poobar » Mon Apr 27, 2009 9:12 am UTC

Spitvalve: The instrument which people far cleverer than myself are allowing me to use is aboard Chandrayaan-1.

Comic JK: Yeah, as someone said, in space it's pretty much just radiation to take your heat away, which is woefully inefficient- counterintuitive, I know. All that sci-fi footage of people freezing instantly after being blasted out of the airlock is bunkum.

Oh, and ideally I'd like to illuminate up to 50 km2 at a time, so the instrument can be used to it's best advantage. That's a lot of scotch tape, but that's my favourite suggestion so far!

Anubis: Alas, my £1000 a year grad student's travel-and-training budget probably wont cover the cost of a half-mile-high roll of scotch tape- this is pure fantasy to stave off the crushing reality of a quiet sun.

The latest idea we can come up with is using the afterglow from Gamma Ray Bursts: http://en.wikipedia.org/wiki/Gamma_ray_bursts, which, as measured by NASA's Swift satellite, contain an unhealthy amount of x-rays. The downsides are that these are fairly shortlived and rare, so that this method is about as efficient as soaking a rotating beach ball by spitting at it from a rooftop. The upside is that these things happen anyway, so are free. Which means I can spend my travel allowance as nature intended*.

*On beer travel.

Wiglaf
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Re: Shedding light on the moon

Postby Wiglaf » Tue Apr 28, 2009 12:54 am UTC

Apparently some weather balloons can get high enough to detect a few X-rays from the sun. I don't know if its possible to put a powerful enough xaser with a clear shot at the moon on one, though.


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