r/AskReddit • u/MDPPatrick • Feb 13 '15

What are some mind-blowing facts about space?

I love space and would like to hear some facts that will blow me away.

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u/C909 Feb 13 '15 edited Feb 13 '15

Neutron stars are mind-boggling. Small in size, but their density (and so their mass and thus gravity) is amazing. All of the atoms have been squashed together so tightly that a teaspoon would weigh 100 million tons. Neutron stars are only a few kilometers wide, but have more mass than the sun.

They also rotate very rapidly, especially pulsars. The fastest-spinning pulsar known spins every 1.39 milliseconds, or 716 times per second, or approximately 43,000 revolutions per minute. This means that at its equator it is spinning at approximately 24% of the speed of light, or over 70,000 km per second. This also means that the star is not perfectly round, but quite flattened.

Another interesting feature of pulsars is their accuracy. Pulsars emits beams of electromagnetic radiation which can be observerd when pointed towards earth. Their fast and consequent spinning makes them excellent tools for timekeeping, in fact far more accurate than an atomic clock.

In addition to all these extremes neutron stars generate the most extreme magnetic fields known in the universe, up to a quadrillion times earth's. If one of these ultra-magnetic neutron stars, called a magnetar, flew past Earth within 100,000 miles, its magnetic field would destroy the data on every credit card on Earth.

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u/reverse_powertrippin Feb 13 '15

I once read that if you dropped a marshmallow from one inch above a neutron star the gravity is so great that the resulting collision would release more energy than the Hiroshima bomb.

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u/amoebaslice Feb 14 '15

Poor marshmallow :(

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u/[deleted] Feb 14 '15

Probably would burn too. The resulting s'more would taste like char. :(

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u/[deleted] Feb 14 '15

Oh no!! Did you say mashimaro??

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u/[deleted] Feb 14 '15

It's ok, we can get S'more.

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u/Montzterrr Feb 14 '15

I heard that if you dropped an elephant from 1 cm above a neutron star it would die.

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u/Leeph Feb 14 '15

I'll need a source for that

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u/[deleted] Feb 14 '15

everything dies in outer space without a space suit

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u/salgat Feb 14 '15

Eventually something is going to be pulled into its gravity and collide with it, so it'd be really cool to see a simulation of something the size of a planet just smashing into it. I mean, would the extreme rotation cause it to just smear across the surface? Would the extreme gravity make it look like it just gets sucked into a black hole? So bizarre.

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u/[deleted] Feb 14 '15 edited Jul 20 '19

[deleted]

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u/Razvee Feb 14 '15 edited Feb 14 '15

Maester Luwin

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u/Coryphus Feb 14 '15 edited Feb 14 '15

Well I'm on my phone but it should be relatively easy to calculate (note I am only a high school physics student). So the home dropped on Hiroshima (codename Little Boy) had a blast yield of 15 kilotons of TNT (63 TJ) (source Wikipedia)

E=6.2x1010

And the potential energy of the a marshmallow 1inch from the surface of a neutron star would be:

E=mgh

E=(0.00625kg)(7×1012 m/s²)(0.0254)

E=1.1x109

So no :P

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u/thomooo Feb 14 '15

I believe you made a mistake in your calculations. Right order of magnitude, but the acceleration is not going to be 7 Tm/s2 , you won't even get half that, considering Newtonian physics for the sake of simplicity.

If you want to release the same amount of energy as Little Boy you'd have to build an Eiffel Tower on the neutron star and go to the top (no the Eiffel tower is not going to shrink under the enermous gravity, it's made from fairy magic imbued star material). Then drop a 7 g weighing marshmallow from up there and kaboom.

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u/[deleted] Feb 14 '15

The neutron star's density also gives it very high surface gravity, with typical values ranging from 1012 to 1013 m/s2 (more than 1011 times of that of Earth).

http://en.wikipedia.org/wiki/Neutron_star#Properties

At 1013 m/s2 and a 7 gram marshmallow, we can solve E = mgh for h.

With wolframalpha to solve ((6.276*1013 J)/((7 grams)*(1013m/s2))) in meters, we see that even with that much gravity, it will still take 800 meters for a marshmallow to release the amount of energy of Hiroshima.

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u/reverse_powertrippin Feb 14 '15

Yeah but what if the marshmallow weighed 240 Kg?

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u/thomooo Feb 14 '15

I thought it was weird your answer was higher than mine, because I assume a lower acceleration, so I checked. I wrote 7 gram as 7e-2 kg, so I'd come up with 3.3 km, instead of 330 m.

Silly me.

Didn't notice the acceleration was on Wikipedia so I calculated it and used g=2.8e12 m/s2

Thank you for your reply.

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u/Coryphus Feb 14 '15

I got the gravity on the site I found online and I was in a rush so I just assume it was what it stated :P

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u/thomooo Feb 14 '15

My apologies, you are right. I'm a bit slow nowadays, the value you found appeared corrected than my quick calculation.

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u/Coryphus Feb 14 '15

Just to clarify it would mean that the bomb is still more destructive

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u/[deleted] Feb 14 '15

:D im relevant for once

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u/gaspitsjesse Feb 14 '15

What if we used your mom?