[Tycho?]

If you want a realistic scenerio' date=' rather than a vanishing Sun, a rogue planet or brown dwarf could pass through the solar system. It's gravity could eject Earth from the solar system. It's highly unlikely, but more likely than the Sun simply vanishing.

 

I imagine ocean currents would be able to keep some islands habitable for months.[/quote']

 

Months? I rather doubt that.

http://www.google.com

http://www.wikipedia.com

Meh, I stopped watching. That isn't actually showing you how to visualize anything, its just explaining it (in a way which seems quite innaccurate, but then I dont know much about these proposed higher dimensions).

For example, they describe the 4th dimension (time) as a line, presumably seperate from 3 dimensional space. Which it is not. Just as the 3 spatial dimensions are at right angles, the 4th is at a right angle to that [err, is this a valid statement?], giving us 4 dimensional space time. Which is exactly why its so hard (impossible, I think) to visualize. That little animation does not assist in that.

venus also has alot less mass so there would be less heat present.

 

 

as for the earth' date=' if you believe the theories about a uranium core at the center producing the heat necessary to keep the core spinning, then we could still use geothermal energy to keep ourselves alive with or without the sun.[/quote']

 

Venus's atmosphere has significantly more mass than that of Earth.

 

I dont think its uranium keeping the core molten. But even if its not, geothermal will remain viable for a long, long time regardless of what the sun does.

That depends on how much of the effect is from the object itself and how much from terrestrial debris from the impact.

 

If the terrestrial debris is a significant effect' date=' then the more surface area of the object you expose, the better off you are. You want to decrease the net impact energy. Terminal velocity varies as sqrt (Weight/Area), so the associated kinetic energy varies linearly. And W decreases faster than A as you get smaller (cube vs square dependence). And that's not even looking at the loss of material due to ram pressure heating; more exposed surface area should burn away more material prior to impact.[/quote']

 

Yes, so you wouldn't get the huge impact crater sort of deal. But I'm saying that if its a really really big one, ecosystem killer kind of thing, having it burn up will only buy you time.

 

The object that is believed to have killed off the dinosaurs was estimated to have an impact energy of 5.0×10^23 J. Earths atmosphere has a mass of about 5.1x10^18 kg. Specific heat capacity of air is 1.005.

 

Q=mcΔT

 

(5.0×10^23 J) = (5.1x10^21 g)(1.005 J/gK)ΔT

 

ΔT= 97.55 K

 

 

....what the hell? My argument is that even if such an object were to totally burn up in the atmosphere, the heat and dust added would still cause huge problems. But I must have made some mistake, because I dont believe that a singe object could raise the temperature of earths atmosphere by almost 100 degrees. Could someone check my work and see where this problem lies? There are several simplifications, for example 1.005 is the specific heat capacity of air at standard conditions, so this would obviouslly be different say 50km up. But since most of the atmosphere is close to the ground I figured I'd be able to get away with it. But there must be something wrong here.

 

http://en.wikipedia.org/wiki/Chicxulub_Crater

http://en.wikipedia.org/wiki/Specific_heat_capacity#Table_of_specific_heat_capacities

http://en.wikipedia.org/wiki/Earth%27s_atmosphere#Density_and_mass

venus will not take much time to drop ot its temp

even though it has huge no of greenhouse gases

venus will be cold planet within few mints only not days or years.

Uh, is english your native language? Cause it could use some work.

I assume "mints" means minutes. And with Venus's greenhouse effect and extremely thick atmosphere it would take longer than earth to cool down significantly

how about the Asteroid belt? or any one of inumerable objects out there, that we don`t even know about.

Well the asteriod belt would by flying off into space as well.

And has been mentioned, it probably wouldn't matter anyway. The asteriod belt isn't like how its portrayed in movies, with rocks constantly smashing into eachother, providing a daring challenge to any space craft flying through. Its mostly empty in real life. When one of the voyager probes was passing through the asterioid belt, they had to alter its course to get it close enough to an asteroid to study it.

But that's one strategy. Smaller objects would be more likely to burn up in the atmosphere.

Yeah, if its a small one and the goal is to just blow it apart. But if its a big one, like end of humanity kind of big, then it wont really matter if its in pieces or not. Your still going to be adding all that heat and dust to earths atmosphere, causing huge climate change.

One of the big problems that has only recently begun to be solved is that we don't know the composition of the objects we might have to deal with so have no idea how much of the impact would be obsorbed by the object....

Very true. Its now believed that many asteriods are little more than clumps of rock held together by gravity alone. Shooting something into an object like this would just disrupt it, but not deflect its course.

That would be something...

 

 

I actually doubt they will' date=' to prevent panic. But still, I am trying to think realistically:

We said up until now two important aspects.

 

1. Big meteors that can cause great damage to the planet are "on target" as we speak. Far away, but on target nontheless.

 

2. We have great difficulties tracking and finding these objects, and we find them at the "last moment".

 

Those two combined: Do we have a chance?? by the time we find them, will we have enough time to divert them?

 

~moo[/quote']

 

Right now we would have to detect an object very early on; we would need months or years to get a mission together to be able to push any such object off course. As you mentioned, seeing these objects very early is not exactly our specialty.

 

I'd say; right now, we'd be ****ed. We need another 50 years of infrastructure in space, experience, technology and telescopes. Then we might have a chance.

Well tycho why dont you go and tell NASA they are wrong then! Thats what they have stated in scientific journals and I think your underestimating how destructive and hot a red giant is in camparison to the sun at the moment!

 

And thats rich coming from you as some of you started insulting me first. I have credibility because I am correct. How many times do I have to spell it out to you retards that a relatively small change could disrupt and lead to events that make earth uninhabitual in a few thousand years. Why dont you go and read a book before you try and comment on subjects you dont know enough about.

We get plenty of idiots here' date=' usually they arn't as aggresive as you are though.

I am quite aware of what is going to happen when our sun goes into its red giant phase. This will not be for at least hundreds of millions of years, if not billions. If you can show me a NASA paper, or any other reputable peer reviewed paper that says the sun will go into a red giant phase in [i']a few thousand years[/i], I will take back what I say. (or if you can show me that a red giant sun would cause temperatures of 1 million kelvin on mars).

My position is that you made up some bullshit. Post your sources, show me that the sun will go red giant in a few thousand years. Show me that it will result in temperatures of 1 million Kelvin on mars. Since you arn't going to do that, shut the hell up.

You are misunderstanding.

You dont "bend" the laws of physics. If you do, it just means that our understanding of that particular phenomenon is incomplete.

Physics is not rigid, it is always changing as new theories come about. So this may mean for example that a way to travel faster than c will be discovered. This does not mean you are breaking a physical law (law of phyics is a term with little meaning anyway), only that our initial understanding was not complete. Its unlikely though, given our current understanding.

as far as I can see' date=' you`de need to calculate the mass of the Earth and latent heat energy contained therein, along with rate of emission (it would decline on a non linear scale), as the temp dropped in literaly Days, there would be no cloud cover either (works a little like an IR blanket), and so the temp would be lost at a greater rate etc...

the Oceans would take a Very long time to freeze, even enough to walk across from the UK to Canada for example, or pole to pole. probably in the order of several months (prividing that we maintained our orbit around this dark sun)

this would NOT be the case if the Sol suddenly vanished!

a moving object will maintain its course unless acted upon bt another force. and so the second Sol vanished, the earth would continue off into space, and more than likely hit something that would generate Plenty of heat! long before you`re all dead! [/quote']

 

Pshh, hit something? What would the earth hit? It would fly off into void.

 

But yeah, as has been mentioned, the atmosphere would go below freezing after a few days. Ocean would take much longer. With the large difference in temperature between the water and the air you'd pretty much cover the earth in fog, which might provide a bit of insulation (well... probably not enough to make a difference). The tides would also keep water moving and delay the freezing. The deep oceans would stay liquid for thousands of years, perhaps indefinately. You have tidal actions, as well as geothermal output.

Right, one stupid person at a time. First CPL and all others, yes the sun will become a red giant in the time frame you all stated but when the sun does become a red giant it will swallow mecury, heat mars to 1 million kelvin approximately and incinerate most of the inner planets of the solar system.

I hate it when people make stuff up to impress other people. Mars will not become 1 million kelvin. 1 million kelvin is a great deal hotter than the surface of the sun, only towards the core where fusion is taking place are you going to get temperatures that high. Mars will never be 1 million kelvin nor anywhere close to it.

And you should be careful about insulting people here, since you were the one who said that the earth would be uninhabitable in a few thousand years due to the sun, which pretty much removes any credibilty you may have had.

Can you add Sources? What did it do to the invironment?

You keep on saying that you arn't seeing this mentioned or can't find any info about it. Just use google. I typed in "meteor norway" and the first hit told me all I wanted to know.

Exactly insane alien. Its been predicted that we are supposed to have an object penentrate the atmosphere by 2052. Space isnt a peaceful place but a hostile world and its extremely common having near (astronomically near) misses but i wouldnt worry' date=' objects hitting earth should be the least of your survival concern (especially living somewhere like USA, think about the caldeara at yellowstone, that would worry me if i were you!).

 

It is certain that within the next few thousand years the earth will be un-inhabital (due to the sun) but many scientists predict that within the next hundred years there are going to be several disasters to wipe us out completely. Foreign objects striking earth is just one but there are so many others before fossil fuels or supposed "global warming" that enviromentalist idiots rave about is even an issue. Point is dont be afraid about the human race being wiped out, it isnt that great anyway.[/quote']

 

 

Objects "penetrate the atmosphere" all the time. A fairly large one hit in Norway just a few weeks ago.

Can anybody make sense out of the above post? I know I can't.

A 400m meteor is fairly large; debris from the impact could get large enough to hit the surface of the earth. Although I doubt much, if any damage would be done. A much larger object hitting the moon could cause significant damage to earth however.

This seems like the sort of thing that experiments should/have been conducted on. Have mice get pregnant and give birth on the ISS or something, observe the results.

Uh, well, your height changes while on earth actually. While walking around your back gets compressed due to gravity. If you get up in the morning, measure your height, and then measure it again after being on your feet the whole day you will be shorter.

With no gravity to compress you, you will just "stretch out" in space, and compress back down after you stood in gravity.

Anything that effects time is a laughable excuse for lack of information.

Be careful what you say is laughable when you dont seem to know what you're talking about. Time dilation do to SR and GR (SR in particular) has a strong theoretical background, and more importantly has been confirmed to exist. What information are we lacking, exactly?

I have to be honest, some of you people are very very....i dont know....well informed on pretty much anything i could ever have a question about.. relating to science that is. So uh...cheers!

Well this is a science forum! And a good one, a number of people in the physics section are actually physicists; its what they do for a living. Certainly adds some legitimacy to the posts that you dont get in most other places on the net.

...does lack of sleep actually kill braincells? I'd be skeptical that lack of sleep could cause you physical brain damage, regardless of how often it occured.

Oh, it looks to you like entropy has been redefined to fit the Second Law? In your highly educated opinion?

Just because you dont know what you're talking about hardly means that the entire physics community is wrong. Go and talk to that physics prof you mentioned, that at least is a good idea.

3. What we can logically estimate this force will be like:

*The force is constant, our notion of time doesn't stop.

*The force is individual.

*The force is out of our control, we cannot fastforeward, pauze or rewind.

*The force is not distorted by the presence of energy, be it in the form of weak force, strong force, EM or gravity (gravity effects the dimension itself which is material, not our notion of time) so the force is probably metaphysical (not made up by the same energy as everything else in our universe that we know is made up out of).

This 3rd point is kinda messed up. What force is being talked about here? And the passage of time can be manipluated in some ways, at least in comparison to others. You can move at an extremely high velocity relative to some observer, plus a strong gravitational field will indeed alter how time passes in comparison to someone else.

And I dont see what any of this has to do with athiesm or religion of any kind.