# Tag Info

1

I'm not entirely sure what you mean about 'pulling hydrogen', all bodies, whether they be planets or literally human bodies, will pull hydrogen via gravity. Earth can lose the H it attracts as H is so light that it can have speeds greater than the escape velocity (just due to random thermal motion). Perhaps Jupiter is sufficiently massive that this happens ...

2

Jupiter will never (not on any timescale like the lifetime of the Sun anyway) accrete enough mass to begin hydrogen fusion. It would need to accrete 12 times its current mass to undergo a brief period of fusing its interior deuterium and to accrete more than 70 times its current mass to attain a central temperature high enough to sustain hydrogen (pp chain) ...

0

There was discussion around what to do with Galileo since it was contaminated with Earth bacteria and risked to contaminate one of Jupiter moons if left to orbit untended. One of options was to send it to Jupiter - then one off concerns raised was that it had plutonium reactor and could ignite Jupiter but was discarded as unrealistic.

1

From the question you've linked to, I assume you're asking what would happen if a dense and insanely huge water/ice body was to undergo strong gravitational collapse. Stars are made up of Plasma, and Plasma is extremely high energy stuff. The pressure energy density on the molecules during the gravitational collapse process is more than enough to rip ...

5

You can't have a "ball of ice with the mass of sun", because the ice in the middle of the ball wouldn't be strong enough to support the weight of the ice on top of it. Instead, the ice would collapse under its own gravity. This would cause the pressure and temperature inside the ball to increase until the water molecules that make up the ice would break up ...

1

Short term, the ice would be vapourised as it fell. It would mix with the sun and form a bizarrely metal-rich star of twice the mass. Such a star would have a much more opaque envelope. This leads to (once an equilibrium is reached) the final star being much less luminous and cooler than a 2 solar mass star of more normal composition. It would probably be ...

11

This would be a highly energenic event, a gravitational collapse in combination with the initial inward velocity of 1000km/s (which is greater than the escape velocity at the surface of the sun). There would be some type of nova event initially because the hydrogen already present in the sun would be compressed by the infalling new material, greatly ...

7

If ice is "all around the sun" I fail to see how it can be moving at a velocity of 1000 m/s inwards. The mass of the sun is $2\cdot 10^{30}\mathrm{\;kg}$ and the radius $7\cdot 10^{8}\mathrm{\;m}$. The thickness of a shell of ice with that inner radius and mass would be (assuming the usual density of ice of about 0.9x that of liquid water) approximately ...

0

First and most important effect of having two sun sized bodies in our solar system very close to each other is that this new system will throw the planetary motion off its course, and there will be chaos(Noticeable chaos right at the moment when lets us assume the ice appeared 1000 km away from sun out of nowhere). Gravitational pull will be twice as much as ...

3

The first thing you'll notice is that the Sun stops shining. It still produces heat and light, but everything is stopped by the thick layer of cold ice. The Sun however is not completely cold. The core is still active, even more than before. You doubled the mass, so the Sun has a higher pressure and thus can fuse easily hydrogen atoms together. The net ...

-1

I agree with what BowlOfRed said, but I'm going to give an answer with a different nuance. So why is the night-sky dark rather than uniformly painted at the brightness of an average star? Because the universe isn't infinite. Big bang cosmology describes a universe that started small some 13.8 billion years ago and has been expanding ever since. It's been ...

3

Olbers’ Paradox says that in an infinite universe every line of sight will end on a star. That statement is incomplete. The paradox requires not only an infinite universe, but also one that is both static and infinitely old. Neither of the second two statements are true for our universe. Your question considers the effect of aging. As our position ...

1

Technetium is not found on Earth in chemically significant quantities because its most stable isotopes (Tc-97 and Tc-98) have half-lives of about four million years. Any technetium that was incorporated into the Earth when it formed, four billion years ago, is now diluted by a factor of roughly $2^{-1000}\approx 10^{-300}.$ The earth only contains $10^{40}$ ...

2

As John Rennie correctly says. Tc is formed by neutron capture in the s-process along with many other heavy chemical elements (Ba, Sr, Eu, Pb etc.). The conditions for the s-process require a neutron source. This is provided by alpha capture onto carbon 13, or sometimes neon 22 in more massive stars. A plentiful supply of carbon 13 only exists (at the right ...

4

This is really the same as my answer to your later question (I saw the later question first). Technetium is thought to occur mainly by slow neutron capture. Repeated neutron capture in a complex chain of reactions eventually produces Technetium. There are details of the reactions in this PDF. There is a paper here suggesting that it may also form from ...

0

I found this paper discussing the production of promethium in stars. The paper suggests several possibilities: Fission of heavy or superheavy nuclei Spallation of heavy nuclei by high energy protons Reactions of Nd and Sm with low energy nucleons: the s-process The longest half life of any promethium isotope is 17.7 years, so it isn't going to be left ...

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