Bad Astronomy and Universe Today Forum - Space/Astronomy Questions and Answers http://www.bautforum.com/ Got a space/astronomy question? Get it answered here. en Fri, 20 Nov 2009 22:04:05 GMT vBulletin 60 http://www.bautforum.com/images/misc/rss.jpg Bad Astronomy and Universe Today Forum - Space/Astronomy Questions and Answers http://www.bautforum.com/ The Gemini Programme http://www.bautforum.com/space-astronomy-questions-answers/96973-gemini-programme.html Fri, 20 Nov 2009 21:49:39 GMT Hi, all!

I haven't posted in a while but I am an, enthusiastic, lurker and read here regularly.

Anyway. I am resident here in Scotland and today I spent the day at the Scottish National Museum ( in Edinburgh and well worth a visit). They have a discovery section for families and I ran across it this afternoon.
One of the exhibits is, claimed to be, a Gemini Capsule. However it has landing gear ( yes, wheels, an undercarriage ). The explanation that goes along with the exhibit says that NASA were trying to perfect a land landing system for Gemini as sea touchdowns were considered too dangerous!
It looks real and the info given seems plausible, but the, few, staff I could speak to were unable to give me much information about it.

Did this exist? and why haven' I heard about it before? ]]> Space/Astronomy Questions and Answers johnb http://www.bautforum.com/space-astronomy-questions-answers/96973-gemini-programme.html Suns apparent size- my maths are wrong http://www.bautforum.com/space-astronomy-questions-answers/96968-suns-apparent-size-my-maths-wrong.html Fri, 20 Nov 2009 20:44:46 GMT Hi,

I am preparing a demo of solar system layout but my maths seems suspect.....

I have some planet images printed on card that I will be placing in correct to scale distances in a 10 metre room. The problem is my maths must be wrong. When I then say 'now these pictures of planets are actually massively blown up so that you can see them here. If the solar system was as small as this room, then the planets would be microscopic and we couldn't see them.'

That's what my maths says... even the sun comes out as being 1/100 of a millimetre at that scale. But if that were true then why can we see a visible disk on Jupiter through even low power binoculars?

I know I am wrong... just not sure how often or where... :) ]]> Space/Astronomy Questions and Answers WalrusLike http://www.bautforum.com/space-astronomy-questions-answers/96968-suns-apparent-size-my-maths-wrong.html Moving planets around. (Gravity) http://www.bautforum.com/space-astronomy-questions-answers/96945-moving-planets-around-gravity.html Fri, 20 Nov 2009 13:05:09 GMT I've been told that if say Venus was moved to an orbit around the sun similar to Earth, that the orbits of the planets would be unstable due to effects of gravity. (Say as far away from the Earth as it could be though.)

If this is true, is there information out there that can help me understand this better?

Thanks. ]]> Space/Astronomy Questions and Answers Beer w/Straw http://www.bautforum.com/space-astronomy-questions-answers/96945-moving-planets-around-gravity.html venus with an atmosphere like earths http://www.bautforum.com/space-astronomy-questions-answers/96942-venus-atmosphere-like-earths.html Fri, 20 Nov 2009 09:29:51 GMT Im just wondering what the average temperature on venus would be if it had an atmosphere that was identical to earths atmosphere. Is venus within the "life zone" so to speak? ]]> Space/Astronomy Questions and Answers kenneth rodman http://www.bautforum.com/space-astronomy-questions-answers/96942-venus-atmosphere-like-earths.html What is the fate of matter? http://www.bautforum.com/space-astronomy-questions-answers/96938-what-fate-matter.html Fri, 20 Nov 2009 04:29:59 GMT I've heard it evaporates/disintegrates over a long enough time scale..
is this true? And if so what is this disintegration called? ]]> Space/Astronomy Questions and Answers Frog march http://www.bautforum.com/space-astronomy-questions-answers/96938-what-fate-matter.html <![CDATA[Comparing the relationship between the volume & surface area of a sphere]]> http://www.bautforum.com/space-astronomy-questions-answers/96906-comparing-relationship-between-volume-surface-area-sphere.html Thu, 19 Nov 2009 20:31:04 GMT I wanted explore the relationship between the surface area and volume of a sphere as a possible metaphor for the expansion of the universe. Don't know if this is an acceptable thing to do, but I wanted to explore it. So here's the logical path I followed:

As Pamela and others have chosen a balloon with dots on it as metaphor for the expansion of the universe, I wanted to see what it would look like from the two point of views in this metaphor; the surface of the balloon & the interior of the balloon. So I solved for "r" in both Surface Area & Volume equations, plugged them into alternating equations & graphed them.

SA of a sphere = 4*pi*r^2

V of a sphere = (4*pi*r^3)/3

Solving for r on each I get:

r (SA) = [SA/(4*pi)]^(1/3)

r (V) = [3*V/(4*pi)]^(1/3)

And plugging them into the opposite equations is:

SA = 4*pi*[3*x/(4*pi)]^(2/3) (with respect to Volume)

V = 4*pi/3*[x/(4*pi)]^(3/2) (with respect to Surface Area)

See the attachments for the graphs

To me the Surface Area equation shows the relationship of the 2nd dimension to the 3rd dimension, being volume, as it changes from the point of view of the 2nd dimension. And the Volume equations shows it from the opposite view.

What I'm curious about is two things:

1) If these same relationships described above could both be shifted up one dimension to time & space (the 4th & 3rd), would they keep the same features?

2) If that's the case could we determine the shape of the universe (space) through how we're experiencing it by working the equations backwards?
Attached Images
File Type: png SA with respect to V.png (54.8 KB)
File Type: png V with respect to SA.png (58.3 KB)
]]> Space/Astronomy Questions and Answers grnegz http://www.bautforum.com/space-astronomy-questions-answers/96906-comparing-relationship-between-volume-surface-area-sphere.html how does our sun work http://www.bautforum.com/space-astronomy-questions-answers/96878-how-does-our-sun-work.html Thu, 19 Nov 2009 06:18:36 GMT I know my understanding is technically wrong, but if I have the gist of it correct I would like to ask you a question or more.
I have no math skills but am cursed with curiosity. I would only hope to understand a simplified layman's take on things. It seems these (super simple explanations for complete and utter morons like me) aren't easy to find that cover every specific aspect of physics. (if physics is even what I'm asking about, I'm not sure)

I had thought for a long time that the (our) sun works because of tremendous pressure causing some kind of atoms to merge and that merging
caused a photon to be released. The actual high pressure caused the merger.

The other day I saw an article that said our sun works (at least in part, if not completely) due to quantum tunneling. Something about the conditions in the sun don't allow enough energy in and of themselves to cause the above mentioned merger of two atoms (and the resultant photon release.)

The article led me to believe that without quantum tunneling the sun would not be close to like it is now.

Are both or either of these ideas correct? (from a simple non technical layman's veiw)

If both ideas are kind of OK for a layman's understanding then I have more questions:

Is it actual pressure and/or heat that allows or causes tunneling in our sun or:
Does the heat just make things move around faster creating more opportunities for tunneling?
Does the pressure cause atoms to be closer together making it easier for tunneling to happen because of a physical closeness between the atoms?
Am I asking in the three above questions if Heisenberg's uncertainty is affected by heat and/or pressure?



Thank you kind people, ]]> Space/Astronomy Questions and Answers geeyathink http://www.bautforum.com/space-astronomy-questions-answers/96878-how-does-our-sun-work.html Is something going on with Sirius? http://www.bautforum.com/space-astronomy-questions-answers/96874-something-going-sirius.html Thu, 19 Nov 2009 05:47:47 GMT I was watching the sky tonight and saw Sirius flickering madly and flashing red, blue and green. I took some video of it, and I looked up any breaking news. There was nothing to be found, however. I know it doesn't sparkle like that all the time. Does anyone have any news? ]]> Space/Astronomy Questions and Answers Lady Krimson http://www.bautforum.com/space-astronomy-questions-answers/96874-something-going-sirius.html Satellite limits http://www.bautforum.com/space-astronomy-questions-answers/96873-satellite-limits.html Thu, 19 Nov 2009 04:27:03 GMT Ok.. gonna try to explain what I mean... Is there any limit to how many satellites, moons, that a planet can have? Can Earth like moons form around planets if so is there minimum size to the planet? Can Earth like planets have multiple moons? Why am I asking... because I am trying to create a game that creates a lot of planets and is fairly accurate... I am dividing up planet sizes into classes that are pretty much like so... Asteroid = 0-1,000km Tiny = 1,000-10,000km Small = 10,100-30,000km Medium = 30,100-70,000km Large = 70,100-150,000km Gas Giant =36,000-1,400,000km They are also each broken down into types of planets... Icey (Pluto) Metal (Mercury) Rockey (Moon) Ocean Caustic (Venus like) Terran (Earth like probably gonna change it to garden world) So I need to know roughly how many moons each size range could support...It seems to me... that tiny planets can have 2+ asteroid moons and Small can have at least one tiny moon, but I also know Gas Giants can have 15+ so...can anyone help me figure some realistic numbers for these? Asteroid = 0 Tiny = 3 Ast. Small = 1 Tiny + 1 Ast. or 4+ Ast. Medium Large Gas Giant 15+ Ok.. gonna try to explain what I mean...

Is there any limit to how many satellites, moons, that a planet can have?
Can Earth like moons form around planets if so is there minimum size to the planet?
Can Earth like planets have multiple moons?

Why am I asking... because I am trying to create a game that creates a lot of planets and is fairly accurate...

I am dividing up planet sizes into classes that are pretty much like so...
Asteroid = 0-1,000km
Tiny = 1,000-10,000km
Small = 10,100-30,000km
Medium = 30,100-70,000km
Large = 70,100-150,000km
Gas Giant =36,000-1,400,000km

They are also each broken down into types of planets...
Icey (Pluto)
Metal (Mercury)
Rockey (Moon)
Ocean
Caustic (Venus like)
Terran (Earth like probably gonna change it to garden world)

So I need to know roughly how many moons each size range could support...It seems to me... that tiny planets can have 2+ asteroid moons and Small can have at least one tiny moon, but I also know Gas Giants can have 15+ so...can anyone help me figure some realistic numbers for these?

Asteroid = 0
Tiny = 3 Ast.
Small = 1 Tiny + 1 Ast. or 4+ Ast.
Medium
Large
Gas Giant 15+ ]]> Space/Astronomy Questions and Answers Durakken http://www.bautforum.com/space-astronomy-questions-answers/96873-satellite-limits.html Galaxy Formation http://www.bautforum.com/space-astronomy-questions-answers/96849-galaxy-formation.html Wed, 18 Nov 2009 20:41:23 GMT We've been discussing galaxy formation in class. My professor recently made the comment, "We assume galaxy formation is no longer taking place." Can anyone clarify this comment? That is, why do we assume that galaxy formation is no longer taking place? ]]> Space/Astronomy Questions and Answers jonbird http://www.bautforum.com/space-astronomy-questions-answers/96849-galaxy-formation.html NEO observation programs http://www.bautforum.com/space-astronomy-questions-answers/96838-neo-observation-programs.html Wed, 18 Nov 2009 18:37:43 GMT I googled around and looked for info in NASA NEO site, but couldn't find any statistical data, so I'm asking it here:
how much part of the sky, and for how long in a day is it monitored for approaching NEOs? I was quite surprised by the asteroid passed half the GEO orbit near Earth some days ago, being spotted only a few hours before it reached minimum distance, as I thought the sky was constantly monitored for such events.
Is it not? :confused: ]]> Space/Astronomy Questions and Answers jumpjack http://www.bautforum.com/space-astronomy-questions-answers/96838-neo-observation-programs.html largest satellites http://www.bautforum.com/space-astronomy-questions-answers/96833-largest-satellites.html Wed, 18 Nov 2009 17:55:14 GMT On Monday, I watched through a telescope and solar filter while the ISS transited the face of the sun. It was an impressive sight. Although I've seen the ISS plenty of times as a bright star in the twilight sky, the silhouette was very detailed. It was the first time in my life I felt I'd actually seen a spaceship!

But the ISS isn't the only satellite that transits the sun. They all do. And there are thousands of them. And TLE’s are available for most of them. But most are probably too small to see. Does anyone know where I can get a list of satellites by angular size? I'd like to compile a top 10 or so, so I can watch these transits more often. ]]> Space/Astronomy Questions and Answers tony873004 http://www.bautforum.com/space-astronomy-questions-answers/96833-largest-satellites.html Planet Rotation http://www.bautforum.com/space-astronomy-questions-answers/96817-planet-rotation.html Wed, 18 Nov 2009 15:07:23 GMT I'm still rather unclear on this issue.
From what I heard from school teachers, the Earth does a full 360 in 24 hours ( a day). So I was wondering, does this apply to every planet? If not, why?

Thank you. ]]> Space/Astronomy Questions and Answers Aurora32 http://www.bautforum.com/space-astronomy-questions-answers/96817-planet-rotation.html peak wavelength of CMB http://www.bautforum.com/space-astronomy-questions-answers/96813-peak-wavelength-cmb.html Wed, 18 Nov 2009 13:30:23 GMT This Wiki link shows the Wien displacement for a black-body spectrum that is used to find the peak wavelength and peak frequency of the CMB pressure. The problem is that when one finds the peak wavelength in terms of dP/dw and then finds the peak frequency in terms of dP/df and then finds the peak wavelength using that with w = c/f after changing all of the wavelengths to frequencies in the formula in this manner, then the graph for the same CMB pressure will look slightly different when plotted out each of these two ways and dividing the peak wavelength by the peak frequency will give a constant speed of light that is much less than c. Dividing c by the peak frequency, then, will give a different peak wavelength depending upon which way we do it. For instance, finding the peak wavelength directly for T = 2.72839 K gives around .0019 meters, while finding it in terms of frequency first and then using w = c/f gives .001062 meters.

However, at the very end of the link, it also provides a "compromise" number of 4, that between 5 for the wavelength and 3 for the frequency, which when used, provides the exact same graph for both and we find w * f = c. That gives a single peak wavelength of .001345 meters either way. I had found that using another method as well, and I think it makes the most sense, so wouldn't that be the most likely choice to use as the solution for the peak wavelength and frequency, then, since there is only one graph for one pressure, the same one for both? I know it would depend upon how the peaks are defined, but wouldn't this be the most obvious choice of definition, then, since it provides a single consistent peak wavelength instead of two possibilities depending upon whether we find it directly or through the peak frequency found in this manner? ]]> Space/Astronomy Questions and Answers grav http://www.bautforum.com/space-astronomy-questions-answers/96813-peak-wavelength-cmb.html Terra forming Mars with Hydrogen Bombs? http://www.bautforum.com/space-astronomy-questions-answers/96812-terra-forming-mars-hydrogen-bombs.html Wed, 18 Nov 2009 13:20:13 GMT I saw many documentaries about terra forming Mars. Most had ideas about using greenhouse gas producing machines. This would probably be impractical and take thousands of years. What about detonating hydrogen bombs in the north and south poles in Mars. There are dense frozen sheets of CO2 in the poles. These bombs would not be detonated on the ground but from a certain altitude to prevent nuclear fall out. But the intense heat from the hydrogen bombs would be enough to release huge amounts of CO2 gas into the atmosphere from its poles. I saw many documentaries about terra forming Mars. Most had ideas about using greenhouse gas producing machines. This would probably be impractical and take thousands of years.


What about detonating hydrogen bombs in the north and south poles in Mars. There are dense frozen sheets of CO2 in the poles.

These bombs would not be detonated on the ground but from a certain altitude to prevent nuclear fall out. But the intense heat from the hydrogen bombs would be enough to release huge amounts of CO2 gas into the atmosphere from its poles. ]]> Space/Astronomy Questions and Answers Ammonia http://www.bautforum.com/space-astronomy-questions-answers/96812-terra-forming-mars-hydrogen-bombs.html