Would a Planetary Detonation Be Visible from Earth ...

[Dauphin]

Re: Would a Planetary Detonation Be Visible from Earth ...

Originally posted by Gatekeeper
And while I'm on the subject of out-of-this-world questions, just how destructive would gravity waves be? I think such waves a purely theoretical right now, but if they were proved to be real, could they, like water waves, be quite destructive?

Gravitational waves have been indirectly proven (there was a Nobel prize for demonstrating it). They are theoretical still, but generally accepted as being necessary to explain certain phenomena.

Also, 'gravity waves' (as opposed to 'gravitational waves') are something else entirely IIRC.

[Gatekeeper]

Interesting, Dauphin. Off the top of your head, what's the difference between "gravity waves" and "gravitational waves"?

[Perfection]

Wiki knows all.

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

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

[Dauphin]

In addition to that, I recalled something about it in an atmospheric physics class I had many years ago.

[Arrian]

THIS is Seti Alpha Five!! [/Khan]

-Arrian

[Gatekeeper]

The Wikipedia entry on gravitational waves was quite informative, Perfection. Thanks for providing the links.

Now, onto a related question: What sort of star would be necessary to cause trouble in the Solar System if it moved into our region? Let's say it passes through or very near the Oort Cloud. What sort of disturbances would that cause, aside from comets being hurled in-system? Would it have to be a massive star, like a blue giant? Or a compact one, like a white dwarf or neutron star? Would any of these stars cause gravitational waves w/i the Solar System that might be destructive *beyond* the known factor of hurling Oort Cloud debris in-system?

Gatekeeper

[Perfection]

Now, onto a related question: What sort of star would be necessary to cause trouble in the Solar System if it moved into our region? Let's say it passes through or very near the Oort Cloud. What sort of disturbances would that cause, aside from comets being hurled in-system? Would it have to be a massive star, like a blue giant? Or a compact one, like a white dwarf or neutron star? Would any of these stars cause gravitational waves w/i the Solar System that might be destructive *beyond* the known factor of hurling Oort Cloud debris in-system?

Besides screwing up orbits a star of any size passing by really wouldn't have much gravitational effect. To give you an idea of how little the effect is consider an object the mass of a hypergiant passing by the earth, and let's make this 200 solar masses which would be the highest bound of the largest massed star ever observed. That's about 2.7 billion moons. Tidal forces (the forces that would cause disruption within bodies) follow an inverse cube law. That is if it is twice as far out it is 8 times weaker. That would put it 1,800 times as far out as the moon. So for it to have the same effect as the moon on Earth it would have to be 4.7 AU away, which is about the orbit of Jupiter.

The oort cloud is about 1000 times farther then that, making it about a billion times weaker.

[Gatekeeper]

Hmm. So all of these sci-fi books with death stars and Solar System disruptions probably aren't scientifically accurate, eh? Oh, well. I guess they still make for some good, popcorn reading.

Gatekeeper

[Gatekeeper]

Wow! A freaking hypergiant star makes the Sun look like a dust mote!

[Proteus_MST]

Jep,
if you compare the sun to some of them it is as though you compare Jupiter to the sun

[Leifmk]

The oort cloud is about 1000 times farther then that, making it about a billion times weaker.

Yeah; the only significant danger would be perturbations of the Oort cloud eventually causing a large number of new comets.

There's a hypothesis (not popular anymore AFAIK) that periodical mass extinction events in the fossil record might be caused by just such perturbations from a dark but massive body on an irregular orbit around the Sun.

[Dauphin]

If you had a hypergiant at about the orbit of Saturn there'd be more to worry about than tidal effects. A star only 10 times the size of the sun produces 10,000 times the power. Radiation would fry you.

[Lord Avalon]

Probably wouldn't have to worry about vampires, though.

[Gatekeeper]

Ah, well. When have facts ever gotten in the way of a good story? I'll just have to reclassify it as a combo sci-fi/fantasy work ...

Gatekeeper

[Joseph]

If some of you think back, I heard that the Chinese saw something exploded in space prior to 1 AD. It was bright enough to see during day light hours.