XPost: alt.astronomy, alt.fan.heinlein

This is only a partial story.
But still, quite interesting idea.
How fast did an object have to hit the earth,
to blast earth into space?

Was it Jules Verne that wrote a book about this,
"Off on a Comet" ?

yes,
Off On A Comet: Verne, Jules: 9781481853538 - Amazon.com
Amazon.com
https://www.amazon.com › Off-Comet-Jules-Verne
Wikipedia
https://en.wikipedia.org › wiki › Off_on_a_Comet
Off on a Comet (French: Hector Servadac) is an 1877 science fiction
novel by French writer Jules Verne. It recounts the journey of several
people carried ...

from https://www.newscientist.com/article/2381928-meteorite-left-earth-then-landed-back-down-after-round-trip-to-space/

Meteorite left Earth then landed back down after round trip to space
Most of the meteorites found on Earth come from asteroids, but a few
come from other bodies like Mars and the moon. Now, researchers say they
have discovered a new kind - a rock originally from Earth that went to
space then came back

By Alex Wilkins

11 July 2023

The meteorite NWA 13188 seems to have travelled to space and back

Albert Jambon

A meteorite found in the Sahara desert in Morocco may have originated on
Earth, before being blasted into space and returning from orbit
thousands of years later. If confirmed, this boomerang space rock would
be the first of its kind we know about.

Almost all the meteorites we have found come from asteroids, but a tiny fraction are from planetary bodies, such as Mars and the moon. These
come from violent impacts that launch debris into space before …

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XPost: alt.astronomy, alt.fan.heinlein

"a425couple" wrote in message news:ZBArM.340585$fNr5.118073@fx16.iad...

This is only a partial story.
But still, quite interesting idea.
How fast did an object have to hit the earth,
to blast earth into space?

-----------------
The minimum velocity for a low Earth orbit is about 7.8 km/Sec. Above 11.2 km/Sec an object will escape Earth's gravity and orbit the Sun. The ratio between them is the square root of 2, a fairly small window. Meteors have arrived at as high as 70 km/Sec, so far. Otherwise everything depends on the fraction of energy transferred as velocity versus destroyed in fracturing,
and velocity lost to air resistance which can be huge. Colliding billiard
balls transfer energy efficiently but rocks shatter.

https://en.wikipedia.org/wiki/Space_gun
A serious complication is that an uncorrected orbit will try to pass back through its launch point. Rockets start vertical so they won't tip over and then curve into the direction of the orbit.

In college Physics a homework problem was to calculate the return time of a weight dropped into an evacuated well that passed clear through an Earth of uniform density. The tricky part was finding a formula to integrate that compensated for depth. It turned out that if you are anywhere within a uniformly thick hollow shell its gravitational attractions in any pair of opposing directions cancel to zero, i.e. you float weightless. You are drawn toward only the mass in the sphere below you. They left that for us to
discover mathematically. Also the return time equals the period of a low
orbit.

https://www.thenakedscientists.com/forum/index.php?topic=46531.0

https://en.wikipedia.org/wiki/Dyson_sphere

https://en.wikipedia.org/wiki/Ringworld

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