Astronomy/cosmology questions...

[Rusty Edge]

https://www.washingtonpost.com/news/speaking-of-science/wp/2017/01/10/study-suggests-earth-once-had-many-moonlets-until-they-merged-to-form-the-moon/?postshare=6681484155959173&tid=ss_tw&utm_term=.4c1f985bfdd6

When I was a kid the Big Bang theory wasn't in vogue. It was the least popular. Simplistic catastrophic one-time event explanations seemed to be too easy to explain The Cosmos. The Original Universe spun so fast that it slung stars spiraling out of the galaxies....Or a gas and debris field gradually condensed into a Universe...or something. Then they found the background noise from the Big Bang and the rest is history.

Traditional thinking had the Moon knocked loose from the Pacific Ocean basin or sprung fully formed from the head of Zeus.  Catastrophic. Well, no chemical evidence of the theoretical Theia, so maybe we're leaning towards fully formed, but how did it Earth shake off a seventh of it's mass and the two pieces not veer in different directions?

I'm fuzzy on the amalgamated moonlets theory, though. Did this happen when the rock was molten, like drops of mercury gently consolidating themselves into a blob? Or did gravity, mass and velocity crush the moonlets into a sphere, the way we might make a snowball from chunky/granular snow?  I guess that's the part of the theory they're working on.

[Buster's Uncle]

New findings confirm cosmos expanding at faster rate than previously thought

[Buster's Uncle]

Hints Of Charge-Parity Violation Detected In Baryons

[Buster's Uncle]

Why Science Will Never Know Everything About Our Universe

[Buster's Uncle]

Giant ring of galaxies scattered during Andromeda flyby challenges Einstein's theory of gravity

[Buster's Uncle]

ALMA Reveals Gigantic Halos Around Ancient Galaxies

[Buster's Uncle]

Is Dark Energy Real? Simulation Suggests Gravity Is Enough To Explain Universe's Accelerated Expansion

[Rusty Edge]

NBC news anchor Lester Holt just showed me a beautiful picture of Jupiter taken by the Hubel, and told me that Jupiter is at it's closest to Earth, only 450 miles.

We replayed it twice. 450 miles!

If it passed that close, wouldn't we lose our Moon, atmosphere, and oceans? Wouldn't that alter our orbit, too?

[Rusty Edge]

For that matter, would people and stuff "fall"/float/levitate to Jupiter, too?

[Rusty Edge]

Or would Jupiter boil and explode as it approached the Sun before it even got that close to us?

[Buster's Uncle]

We'd fry from the radiation.  That would put Earth inside Jupiter's huge Van Allen belts, and they are INTENSE.

[Rusty Edge]

We'd fry from the radiation.  That would put Earth inside Jupiter's huge Van Allen belts, and they are INTENSE.

I didn't even realize they had them.... but it makes sense, now that you mention it.

[Lorizael]

So if Jupiter were magically transported such that its surface were 450 miles away from our surface and somehow kept there, then yes, life on Earth would be unpleasant. At that distance, Jupiter's tidal forces would start to tear the Earth apart, although Earth is very dense, which makes it more survivable. Jupiter's radiation would also be a problem--it is for the satellites we send there, which have to be very careful during close flybys--but Earth's magnetosphere would also offer protection. So the two planet's magnetospheres would interact, and the result would be... complicated... but my guess is probably bad for the residents of Earth given how radiation-blasted Io is.

If Jupiter passed by us and reached a closest approach of 450 miles, it's more difficult to say what would happen because that all depends on the specifics of its trajectory. The faster Jupiter moves as it passes is, the less effect it has, because you can kind of approximate its effect on our orbit by adding up the cumulative effect of Jupiter at each moment in time. So the less time it spends around us, the smaller the effect. Still, at 450 miles, that's well inside the orbit of the moon, so it would probably screw up both our orbit and the moon's.

Jupiter itself should survive being that close to the sun. It certainly wouldn't explode. Think about all the hot Jupiter exoplanets we've discovered. For some of them, their atmospheres become distended and stripped away by their star, but that takes a long time and being very, very close to the star. The increased temperature on the surface of Jupiter would mean more particles are moving fast enough to escape, but it still wouldn't be boiling.

[Geo]

If it passed that close, wouldn't we lose our Moon, atmosphere, and oceans? Wouldn't that alter our orbit, too?

It might be a fragmentation of Earth (tidal forces).
My gut feeling tells me the Moon would become a new satellite of Jupiter. 350-400 thousand kilometers (Earth-Moon distance) is between the distances Io and Amalthea orbit Jupiter.

We'd fry from the radiation.  That would put Earth inside Jupiter's huge Van Allen belts, and they are INTENSE.

I'm not so sure. Earth has a strong magnetic field as well. And being inside Jupiters' radiation belts (between Jupiter and its belts) isn't a problem, being within is...

[Buster's Uncle]

I meant within...

-And I suspect that at that very closer range, the heat Jupiter radiates might be non-trivial, too.