Science questions not worth a thread I: I'm a moron!

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That lunar eclipse we just had, what might it have looked like if we were standing on the surface of the moon watching Earth pass in front of the sun?
 
madviking said:
A solar eclipse.

Except the Earth is this reallllllllllllllllllly big ole ball.
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I already know that from the perspective of the moon, it is a solar eclipse. What I was wondering is what the eclipse would actually look like given that Earth is a planet with an atmosphere passing in front of the sun instead of an airless rock. I know Earth's atmosphere bends the light so that the moon gets deep red colors, instead of turning black. Basically, I wanna see how distorted the sunlight would appear to be to an observer on the moon during the eclipse.
 
From Earth, the moon looks the same size as the sun, making for stunning solar eclipses -- when the moon blocks out the sun, it's blocking out the star but not the star's corona. From the moon, Earth would be much larger in the sky than the sun, so when a lunar eclipse happens, the corona would either not be visible, or would barely be visible.

I imagine the atmosphere of the earth would be visible as a ring in the sky.

edit: few minutes of google returned this photo of lunar eclipse taken from a lunar orbit: http://blogs.discovermagazine.com/b...does-a-lunar-eclipse-look-like-from-the-moon/
 
contre said:
From Earth, the moon looks the same size as the sun, making for stunning solar eclipses -- when the moon blocks out the sun, it's blocking out the star but not the star's corona. From the moon, Earth would be much larger in the sky than the sun, so when a lunar eclipse happens, the corona would either not be visible, or would barely be visible.

I imagine the atmosphere of the earth would be visible as a ring in the sky.

edit: few minutes of google returned this photo of lunar eclipse taken from a lunar orbit: http://blogs.discovermagazine.com/b...does-a-lunar-eclipse-look-like-from-the-moon/
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That's pretty good, thanks. :)

I was under the assumption that maybe parts of Earth's nightside might appear to have some sort of glow in addition to the ring of light.

Still pretty good though. :)
 
Seeing Earth's light pollution from the moon might need conditions where there wasn't a lot of other light drowning it out.
 
Cutlass said:
Seeing Earth's light pollution from the moon might need conditions where there wasn't a lot of other light drowning it out.
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I didn't mean the light pollution, i was thinking about how the atmosphere might be affecting the sunlight as it passes through the air, considering the moon doesn't go completely black like it would if earth had no atmosphere. Basically I was wondering if it was just a ring of light, or if there was something more in addition to the ring of light.
 
There probably is. The light you can see around the rim of the Earth is probably not exactly where the land is. But from that distance the difference would likely be too small to make out with the naked eye. It isn't, for example, going to be 10% of the air in front of the planet that is getting refracted light. Just a tiny bit of the volume.
 
I was asked the day before yesterday why there are more lunar eclipses than solar eclipses. My answer was that the shadow of earth is much larger than the shadow of the moon so the chance for the moon being in the shadow of the earth is much larger than vis-a-vis.
Is this true or are there any other reasons? (e.g. 12 moon/earth cycles per 1 earth/sun cycle)
 
The moon is a lot closer to the earth than it is to the sun, thus, there's a larger margin of error for the conditions to be "right" -- so it's not just the shadow cone being larger, but where the bodies are in relation to one another.

Also at play is that a lunar eclipse can be seen from a much larger area than a solar eclipse. A total solar eclipse can only be seen in a small path across the surface of the earth. A total lunar eclipse can be seen from almost half the planet (the half that's in night).
 
What would radioactive Sodium-22 be used for?

Checking a liquid-sodium reactor coolant system for leaks? Making radioactive salt to mutate someone's cow?

This question is inspired by the recent seizure by Moscow airport security officials of 18 containers of sodium-22 from a passanger who was about to board a flight to Iran.

Here:

http://news.nationalpost.com/2011/1...ve-material-bound-for-iran-at-moscow-airport/
 
Blue Emu said:
What would radioactive Sodium-22 be used for?

Checking a liquid-sodium reactor coolant system for leaks? Making radioactive salt to mutate someone's cow?

This question is inspired by the recent seizure by Moscow airport security officials of 18 containers of sodium-22 from a passanger who was about to board a flight to Iran.
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As far as I know it is of no use in nuclear engineering.
It would still be really nasty if released into the environment. Sodium can easily be absorbed by all organisms.
 
Yup, sodium-22 would be quite a nice way of blowing out any living being in this planet, especiallt complex ones like ( for example ) mammals in general ( I could see it screwing neurons and heart pretty fast if the dose would be high enough ). OTOH sodium has quite low average permanence time inside the body in most mammals ( unlike calcium and the dreaded strontium-90 ) since it tends to be lost via liquid secretions ( urine, sweat and others ) ... thus added to the +/- 2,5 years half-life, would make quite hard to detect a sodium 22 poisoning if the test was not made in a short time after the entry in the organism.

My educated guess ( take it with a grain of salt ) is that someone was going to play this tune again, but with a smarter choice of "gun" ( after all, we are suposed to have sodium in our bodies, unlike polonium :p ... and for all the effects sodium-22 would not acuse any diferent in standart chemical analysis from the regular sodium 23 ... only if you made mass sprectrography or were chasing for the decay products ( that, to make things worse, is a noble gas stable isotope ) there would be a chance of detecting it ) :/
 
I wonder how much damage radioactive sodium might do to a neuron once transported in by a channel? Is 2.5 years half-life t0o short to be lethal?

Also if the Na-22 decays to Neon-22, is there anything to Neon-22? It's not radioactive. Maybe they're trying to make a neutrino gun? :)
 
Sodium has a much shorter biological half life, a bit less than 2 weeks if I recall right. I'd be tempted to say that'd render its nuclear half life too long to do much damage, but Na22 -> Ne22 is beta decay, like Iodine-131. So even small amounts are harmful, especially when taken internally. Plus you eat a lot more sodium than you do iodine so there's more radioactive material in your body.
 
contre said:
Sodium has a much shorter biological half life, a bit less than 2 weeks if I recall right. I'd be tempted to say that'd render its nuclear half life too long to do much damage, but Na22 -> Ne22 is beta decay, like Iodine-131. So even small amounts are harmful, especially when taken internally. Plus you eat a lot more sodium than you do iodine so there's more radioactive material in your body.
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The real issue is that the human body uses sodium in a lot of critical processes and in a almost ubiquitous way ( I'm thinking in the neuron signal transmission and muscle movement, but all cells are in the end 9/1000 sodium solutions :p ) . Ingestion of radioactive sodium would most likely be very bad for the brain and muscles, not mentioning the good ol'sacrifice target for any radioactive comtaminant, bone marrow ( will all the consequences you can imagine ).

BTW, I decided to look on the nets for a hazard sheet and found this . Quite dangerous stuff, because it is problematic even by simple inalation ....
 
According to the data sheet you linked, sodium has a biological half life of 11 days (which I recalled correctly! yay!) so I'm skeptical anything but deliberate poisoning would have serious neurological effects. Except in cases of deliberate poisoning (eg large amounts ingested), the half-life is too long compared to the biological half-life to really screw you up.

Of course, even small amounts would be bad... I'd expect radiation sickness. Just, you know, not death from accidental exposure.

edit: quick, someone get me 40 monkeys and some Na-22 and I'll get back to you.
 
I seem to recall that Na22 is used in the analysis of materials as an positron source.
 
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