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The Astronomy Thread 
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Joined: Thu Mar 24, 2011 12:44 am
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Post Re: The Astronomy Thread
absalom: the tricky part is making it long term self sustainable, injecting radioactives(which is pretty much what keeps our core molten) is probably the best bet. your idea of microwaving the core to kick start it might be a good idea though.

and you don't really NEED tectonics, sub surface blending should be quite sufficient to keep the mixture nice and even.


Tue Mar 12, 2013 1:36 am
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Post Re: The Astronomy Thread
http://en.wikipedia.org/wiki/C/2011_L4

Just in case someone didn´t noticed yet.

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Thu Mar 14, 2013 7:39 pm
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Post Re: The Astronomy Thread
GeoModder wrote:
It came down a bit late for the centennial celebration of Tunguska. :|

Fortunately astronomical bodies couldn't care less about numerology :twisted:

Back on topic:
According to this, Mars has the strongest greenhouse effect out of the three little gassy rocks in our System as it is. Adding water to the Mars equation is only going to add ice (snow, et al.) and probably just increase albedo cooling it further. Besides a comet impact might just end up blasting off more volatiles than it'll add anyway, wouldn't you think? :idea:

I say we forget about terra-anything that Red Rock, but rather "eat it up" when we run out useful sources of material in the surrounding System. After the scientists and tourists get bored poking around the place that is. Could take a while.

Trantor wrote:
http://en.wikipedia.org/wiki/C/2011_L4

Just in case someone didn´t noticed yet.

Was prompted to look into the event due to an EuroSport broadcast of all things! I sure am out of the loop.. :roll:

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Thu Mar 14, 2013 7:59 pm
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Post Re: The Astronomy Thread
mikk: well, not entirely right, the temperature difference between 'with greenhouse gases and without' was only 5 degrees celcius....not exactly mindboggingly huge, on the other hand mars has a rather low reflectivity, that could be a issue with water, due to ice being a rather good reflector....
but atmosphere does have the slight advantage of being a tad bit larger area to absorb light over.

overall, to get mars to be reasonably terraformed would need three(or maybe four?) things...
#1 shitloads of water, getting a large scale terran biosphere to work without it is a damn near impossibility.
#2 huge ass mirrors in orbit to reflect more light on the planet.
#3 get core molten so we get a magnetic field that protects the planet from radiation and more importantly keeps atmo from being blown away.(slight bonus, ground warming up slightly, probably only a few degrees, but it still counts.)
possible #4 if atmo can't be contained without more gravity, we need to add mass, THIS would pretty much be a plausibility breaker....although i guess it would be simpler to create a planetary wide geodesic sphere to keep atmo contained.


Fri Mar 15, 2013 2:03 am
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Post Re: The Astronomy Thread
And an atmosphere itself is not required at all? (Note: Mars has no atmosphere worth mentioning in this context, which seems to be terraforming). Is this suggesting we should hope to achieve an atmosphere of steam?

To be boring, I'm still on the boat finding ideas of terraforming Mars to be incredilously boring, and comparable to doing that to the likes of our Moon. Now, despite Venus having prominent spin deficit, I seem to find the challenge and far-fetched notion of terraformin that scorched rock intriguing (even if it wouldn't be a practical thing to do with it). I wonder if there's a rule, or many, about sleeping and typing

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Fri Mar 15, 2013 11:36 am
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Post Re: The Astronomy Thread
water vapor, and other stuff thrown up from the impact, but basically, yes....it would greatly help with the next part...spreading some kind of algae or moss like thing to make the actual atmo, water is useful for that.


Sat Mar 16, 2013 2:32 am
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Post Re: The Astronomy Thread
hi hi

I should point out that Venus does not have a significant magnetic field either, but it has a rather thick atmosphere.

(Maybe what they should do is terraform Venus and Mars at the same time. Just take all that extra stuff from Venus, ship it over to Mars... its a win win. :) )


Sun Mar 17, 2013 3:34 pm
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Post Re: The Astronomy Thread
icekatze wrote:
I should point out that Venus does not have a significant magnetic field either, but it has a rather thick atmosphere.


Venus has a significant higher gravity field compared to Mars, and most of what the atmosphere is composed of isn't perhaps so easily broken down by sunlight.

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Sun Mar 17, 2013 5:06 pm
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Post Re: The Astronomy Thread
My understanding is that the composition and rapid movement of Venus' atmosphere generates its own magnetosphere. Some atmosphere is lost to the solar wind, but presumably the large amount of volcanic activity keeps it replenished.

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Sun Mar 17, 2013 6:18 pm
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Post Re: The Astronomy Thread
hi hi

The composition of Venus and Mars' atmospheres is largely the same. Mars is 95.32% Carbon Dioxide, Venus is 96.5% Carbon Dioxide. But Venus has an awful lot more of it.

Both Venus and Mars have an ionosophere that is generated by solar radiation interacting with the atmosphere, and have an induced magnetosphere. The rapid movement of Venus' atmosphere is due to the intense heat, as the atmosphere rotates contrary to the rotation of the planet. (which rotates much, much slower than Mars.) The wind speed also drops to near zero near the poles.

Both Mars and Venus have enough gravity to hold Carbon Dioxide within their gravity well. However, Oxygen seems to be a bit more problematic on Mars, due to its propensity to polarize and recombine when split.

It is my understanding that there is still some debate over how Mars lost its atmosphere. It does lose its atmosphere due to stripping and sputtering from solar winds, but this is also the case for Venus. It is possible that with a thicker atmosphere, like Venus, it would provide itself with better protection.

However, if I was to make a guess, I would bet that the end of volcanism on Mars is what distinguishes it from Venus.

Mars is thought to have lost about 1 bar of atmospheric carbon dioxide over the course of 3.5 billion years, but there is a lot of uncertainty about when Mars lost its magnetic field, how rapidly the magnetized crust formations were overwritten by tectonics and impacts, and the variations of solar winds which are suspected to have been more intense in earlier eras.

A reasonably in depth overview.


Sun Mar 17, 2013 8:01 pm
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Post Re: The Astronomy Thread
Hubble infrared horsehead nebula image.

http://www.spacetelescope.org/images/heic1307a/

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Fri Apr 19, 2013 8:31 pm
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Post Re: The Astronomy Thread
Woah. That is pretty. If we had views like that in our naked eye, half our population would be either poets or astronomists.

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Sat Apr 20, 2013 2:36 am
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Post Re: The Astronomy Thread
Wowzers!


Sat Apr 20, 2013 2:40 pm
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Post Re: The Astronomy Thread
bunnyboy wrote:
Woah. That is pretty. If we had views like that in our naked eye, half our population would be either poets or astronomists.


A sci-fi race that idolized poet astronomers would be a pretty cool one. Hm..

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Sun Apr 21, 2013 1:54 am
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Post Re: The Astronomy Thread
This is actually meteorology rather than astronomy, but it's on NASA's Astronomy Picture of the Day, so... whatever.

Video of a supercell thunderstorm over Texas:
http://apod.nasa.gov/apod/ap130618.html

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Tue Jun 18, 2013 7:22 pm
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Post Re: The Astronomy Thread
That supercell is terrifying, beautiful and truly awesome.


Tue Jun 18, 2013 8:07 pm
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Post Re: The Astronomy Thread
Video representation of large scale 3D galaxy position data: http://vimeo.com/64868713

It's lengthy and slow, but I recommend watching through the whole thing: there's very interesting motion information in the latter half (you can see these multiple great rivers of galaxies flowing into the Great Attractor).

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Tue Jun 18, 2013 8:28 pm
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Post Re: The Astronomy Thread
Another great find; I'll have to watch it more closely when I have more time. That being said, I've heard of the Great Attractor, so i skipped ahead, and suffice it to say, though the flows were plain to see, their scale is nearly incomprehensible.


Tue Jun 18, 2013 8:59 pm
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Post Re: The Astronomy Thread
two more examples to show how small we really are, wow, just wow.


Wed Jun 19, 2013 7:39 am
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Post Re: The Astronomy Thread
Really cool presentation indeed. Found myself thinking that plans for Triangulum colonization should be accelerated, so a push beyond the Local Group could be undertaken.

Meanwhile, I hope you people were, are, or will be having a pleasant midsummer/midwinter day/night; bonfire or not.

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Sat Jun 22, 2013 4:32 pm
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Post Re: The Astronomy Thread
I am not sure if this is old news, but this might be of interest: Three Planets in Habitable Zone of Nearby Star: Gliese 667c
Or directly from the website of ESO (when it works) Link

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Tue Jun 25, 2013 10:00 am
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Post Re: The Astronomy Thread
Video of the September 29-30 coronal mass ejection and the resulting "canyon of fire" on the Sun.



The Goddard center (and the Heliophysics team especially) seem to have someone who knows how to make nice videos.

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Thu Oct 24, 2013 1:02 pm
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Post Re: The Astronomy Thread
Slight change of subject.

Ever since i played Kerbal (we can now do science!! in the carrer mode) i wondered How did the first astronaut and their team calculated the fuel needed to land on the moon, or if you prefer, how did they calculate the mass of the moon prior to that expedition?

I hope it wasnt just a wild guess from it size VS the size of Earth


Thu Oct 24, 2013 1:46 pm
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Post Re: The Astronomy Thread
Any time you can observe two objects orbiting each other, you can use basic physics (Newton's law of gravitation) to determine their masses.

http://curious.astro.cornell.edu/questi ... number=207

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Thu Oct 24, 2013 2:55 pm
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Post Re: The Astronomy Thread
Arioch wrote:
Any time you can observe two objects orbiting each other, you can use basic physics (Newton's law of gravitation) to determine their masses.

http://curious.astro.cornell.edu/questi ... number=207



nice!

so if i have that guys orbiting that girl.... i can determine the girl mass?


Sat Oct 26, 2013 10:28 am
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