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Re: The Astronomy Thread

Posted: Tue Mar 12, 2013 8:36 am
by discord
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.

Re: The Astronomy Thread

Posted: Fri Mar 15, 2013 2:39 am
by Trantor
http://en.wikipedia.org/wiki/C/2011_L4

Just in case someone didn´t noticed yet.

Re: The Astronomy Thread

Posted: Fri Mar 15, 2013 2:59 am
by Mikk
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:

Re: The Astronomy Thread

Posted: Fri Mar 15, 2013 9:03 am
by discord
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.

Re: The Astronomy Thread

Posted: Fri Mar 15, 2013 6:36 pm
by Mikk
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

Re: The Astronomy Thread

Posted: Sat Mar 16, 2013 9:32 am
by discord
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.

Re: The Astronomy Thread

Posted: Sun Mar 17, 2013 10:34 pm
by icekatze
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. :) )

Re: The Astronomy Thread

Posted: Mon Mar 18, 2013 12:06 am
by GeoModder
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.

Re: The Astronomy Thread

Posted: Mon Mar 18, 2013 1:18 am
by Arioch
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.

Re: The Astronomy Thread

Posted: Mon Mar 18, 2013 3:01 am
by icekatze
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.

Re: The Astronomy Thread

Posted: Sat Apr 20, 2013 3:31 am
by Arioch
Hubble infrared horsehead nebula image.

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

Image

Re: The Astronomy Thread

Posted: Sat Apr 20, 2013 9:36 am
by bunnyboy
Woah. That is pretty. If we had views like that in our naked eye, half our population would be either poets or astronomists.

Re: The Astronomy Thread

Posted: Sat Apr 20, 2013 9:40 pm
by Grayhome
Wowzers!

Re: The Astronomy Thread

Posted: Sun Apr 21, 2013 8:54 am
by Count Casimir
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..

Re: The Astronomy Thread

Posted: Wed Jun 19, 2013 2:22 am
by Arioch
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

Re: The Astronomy Thread

Posted: Wed Jun 19, 2013 3:07 am
by Mr Bojangles
That supercell is terrifying, beautiful and truly awesome.

Re: The Astronomy Thread

Posted: Wed Jun 19, 2013 3:28 am
by Arioch
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).

Re: The Astronomy Thread

Posted: Wed Jun 19, 2013 3:59 am
by Mr Bojangles
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.

Re: The Astronomy Thread

Posted: Wed Jun 19, 2013 2:39 pm
by discord
two more examples to show how small we really are, wow, just wow.

Re: The Astronomy Thread

Posted: Sat Jun 22, 2013 11:32 pm
by Mikk
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.