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Forum » SpaceEngine » Science and Astronomy Discussions » Science and Astronomy Questions
Science and Astronomy Questions
WatsisnameDate: Monday, 27.04.2015, 07:22 | Message # 346
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You don't have to be near the object to see its gravitational lensing:






 
n0b0dyDate: Monday, 27.04.2015, 10:50 | Message # 347
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Ok so I watched interstellar and I have a few questions:

1. What happened to the wormhole that was close to saturn once Endurance crossed it and arrived at the Gargandua? I mean there was no reference (visual or otherwise) with regard to it. Was it close to the Gargandua's black hole? Did it collapse/ been destroyed sometime during the course of history/plot of the movie?

2. And now the difficult part: the end of the movie: When Cooper started falling in the black hole shouldn't he die? Shouldn't his capsule collapse/spagghetify crushing/compressing himself togehter with it, being transformed into an amorphous blob/bulge of fluid superhot matter as it approached/crossed the event horizon or at least as it approached the singularity? Or did the Tesseract time machine-thing rescued him before the effects of the singularity kicked in?

Sorry for stupid questions. I am just a sutpid low IQ, mere humanoid biggrin cry


Edited by n0b0dy - Monday, 27.04.2015, 10:53
 
AerospacefagDate: Monday, 27.04.2015, 11:36 | Message # 348
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Technically it's not an astronomy question so I'm going to go with laconic answers.

 
WatsisnameDate: Monday, 27.04.2015, 12:21 | Message # 349
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@Aerospace: His second question is most definitely astronomy related.

n0b0dy:
1: I don't think the wormhole ever vanished or anything, though they certainly don't talk about it much after they arrive. There is one pretty subtle reference, when Dr. Brand (senior) mentions to Murph that they aren't receiving signals from through the wormhole anymore, although they can still send. (It's because of the time dilation near Miller's planet: the crew are now 20-some years in the future.)

It is implied that after being rescued from the black hole by the Tesseract, Cooper is transported to Saturn through the wormhole (hence why he shakes hands with Amelia). After reuniting with Murph he steals a Ranger and heads back through the wormhole again to meet Amelia on Edmund's planet.

2: Good question; this is a little counter-intuitive. In terms of the tidal forces (what causes the "spaghetiffication"), you're actually better off falling into a larger black hole than a smaller one. For the more massive hole, the lethal range of those tidal forces is larger, but so is the size of the event horizon, and the horizon's size grows with mass more rapidly. For a black hole weighing as much as the Sun, the lethal radius is larger than the horizon. For Gargantua, weighing billions of suns, the horizon is larger. You could fall through it and for a long while beyond before the tidal forces kill you.

If you do make that trip, you'll find the tidal forces affect big stuff before small stuff. Think of it this way: the tidal force is simply the difference in the pull of gravity between two places. The bigger you are, the stronger that difference. If you fly into a black hole in a spaceship, your ship is going to be pulled apart before you are. This is what you see happen with Coopers ship, which forces him to eject, and he continues onward in just his spacesuit.

Quote
Or did the Tesseract time machine-thing rescued him before the effects of the singularity kicked in?


Yes. If the tesseract didn't save him then Coop would have died pretty soon afterward.





 
HandbananaDate: Sunday, 19.07.2015, 03:41 | Message # 350
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Would it ever be practical for there to be a (in vacuum) propulsion system where small amounts of radioactive material are expelled from the engine and then shot with a neutron beam to cause a reaction? The difference between this and the proposed drive from Project Orion is that Orion would have made large, intermittent detonations after one another, whereas I'm talking about a device that constantly detonates small quantities of nuclear material without any noticeable pause. I imagine that it would appear similar to conventional rockets, as there would appear to be a constant stream.

If such a method of propulsion is possible, I see two major benefits that did not exist in the concept of Project Orion:

- A constant expulsion of nuclear material would mean a less sudden increase in g-force, and would be necessary only once per 'burn', rather than feeling a sudden push repetitively.

- Since individual pieces of nuclear material would be in far smaller quantities, this would allow for more accurate orbital burns, since the delta-v would be controlled by a variable adjustment of thrust, unlike Orion.





Tonight... you.

Edited by Handbanana - Sunday, 19.07.2015, 22:13
 
HarbingerDawnDate: Sunday, 19.07.2015, 09:21 | Message # 351
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Handbanana, you should look at fission fragment rockets, they're somewhat similar to what you describe.




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HandbananaDate: Sunday, 19.07.2015, 11:11 | Message # 352
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That seems to be almost exactly what I am looking for, I appreciate it.




Tonight... you.

Edited by Handbanana - Sunday, 19.07.2015, 22:12
 
AeroWolfDate: Monday, 27.07.2015, 07:59 | Message # 353
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1,Can a rocky planet get as big as Jupiter or the sun?
2.Also can purple, pink, brown and yellow gas giants exist?
3. How small can a gas 'giant' be?
4. Is it possible for mankind to destroy the universe?





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WatsisnameDate: Monday, 27.07.2015, 09:32 | Message # 354
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1: Yes, but then at that point it usually ceases to be a rocky planet, and instead becomes a gas giant, brown dwarf, or star. smile By the time it's about 10 Earth masses, its gravity has grown strong enough to gather and retain the gases from the surrounding protoplanetary nebula. And if it's the mass of the Sun, then the central pressure and temperature are great enough for nuclear fusion.

2: Hard to say; depends on the atmospheric composition, and how saturated of a color you mean. I would say Jupiter has some brownness to it, and Saturn is a sort of golden yellow. But for a very saturated cartoony color like an all-out magenta, I'd be a bit surprised to find that in nature.

3: This is related to (1), as the minimum size is set by what mass is necessary for the planet to be able to build and retain a substantial gaseous envelope. It also kind of depends on where you draw the line between "a rocky planet with a thin atmosphere" and "a planet with a rocky core and a thick atmosphere". It's a fuzzy boundary, and its where we see a transition from large terrestrial planets (Super-Earths) to planets that look more like Neptune (mini-Neptunes, AKA ice-giants or gas-dwarfs).

4: I like this question! It's a simply stated one, but has a lot of room for different interpretation (what exactly is meant by "destroy the universe"?) and open discussion. I'm not going to answer just now -- I hope for others to add in their thoughts. smile





 
apenpaapDate: Monday, 27.07.2015, 10:06 | Message # 355
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Quote AeroWolf ()
4. Is it possible for mankind to destroy the universe?


I don't think so, and here's my reasoning: if mankind could destroy the universe, other intelligent species could do the same. We know there have to be a large number of them out there, simply by the size of the universe. The universe has been going for 13.7 billion years; if all those species have had the capability to destroy it for that long, one of them would almost certainly have been stupid enough to do it. But the universe still exists, therefore humans can't destroy the universe.

Of course, this reasoning hinges on the assumption that there are many other intelligent species out there. If intelligent life is rare enough that humanity is one of the first intelligent species to evolve in the entire universe, it doesn't work.





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midtskogenDate: Monday, 27.07.2015, 10:45 | Message # 356
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I suppose, if the universe is unbounded, we cannot destroy it, unless there are ways of propagating effects faster than light.

If we can destroy on a smaller scale, say a galaxy or a star system, apenpaap's argument sounds reasonable. But do we know for sure that, say, gamma-ray bursts, aren't just an advanced species' physics experiment taking an unexpected turn? smile





NIL DIFFICILE VOLENTI


Edited by midtskogen - Monday, 27.07.2015, 10:46
 
apenpaapDate: Monday, 27.07.2015, 12:19 | Message # 357
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Quote midtskogen ()
But do we know for sure that, say, gamma-ray bursts, aren't just an advanced species' physics experiment taking an unexpected turn? smile


If I recall correctly, one of the discoverers of one of the more bizarre galaxies out there was famously quoted wondering if it might be an industrial remnant.





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AeroWolfDate: Wednesday, 29.07.2015, 19:46 | Message # 358
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How big can black holes get? Can they keep growing infinatly?




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WatsisnameDate: Wednesday, 29.07.2015, 21:59 | Message # 359
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There is no fundamental upper limit for a black hole's mass. If you keep adding material to one indefinitely, then it will continue growing indefinitely. smile

However, the size of the black holes we find in nature is limited by how much material is available, and how rapidly the hole can swallow it. The growth rate is limited by something we call the Eddington limit, which basically means that if the growth is too rapid, then the accretion disk around the hole would give off so much radiation as to blow away the surrounding material, thus preventing further growth until the accretion disk can settle down again.

Presently, the largest black holes we know of are on the order of ~10 billion solar masses. In the very distant future, the final masses of supermassive black holes is expected to range from about a billion to a trillion solar masses. The largest ones would occupy the centers of galactic superclusters, with smaller holes orbiting around, occasionally merging via the slow decay of orbits or the random interaction. During this time-frame all black holes will also be slowly evaporating through Hawking Radiation. At some point roughly a googol years from now they will have all dispersed into a sea of particles, and the universe will be effectively dead.





 
NikolaAnicic007Date: Monday, 23.11.2015, 17:24 | Message # 360
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Greetings. I would like to ask you fellows a few things that aren't as much about astronomy as they are about chemistry and physics.

How does one calculate the Latent heat of Fusion, the Latent heat of Vaporization and the Latent heat of Sublimation for a molecule?

I am aware that these three values are specific for each molecule, and have found no material that answers my question on the internet.

Known information: Molecular Weight, Energy (in kJ/mol) and bond length.

Hope this helps, I'm wondering this so I could probe into some exotic atmospheres, lithospheres and oceans.

Test Molecule: hydroxylamine (H3NO); 104.687 kJ/mol; Bond Lengths available if needed.


Edited by NikolaAnicic007 - Monday, 23.11.2015, 17:33
 
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