If a large meteor hit the earth100-1000 miles across. how long would it take the shock wave to reach the other side of the earth?

A shock wave would travel right through the Earth and would reach the other side in about 40 minutes (according to PhotonX, which seems about right). However you are probably referring to the atmospheric blast which is somewhat more difficult to predict, as "shock waves" in compressible fluids like air quickly degenerate to sound waves which travel at around 5 seconds per mile. Since the Earth has a half-circumference of about 12,000 miles, this implies that the blast would reach the antipodes in a maximum of about 16 hours. The actual time of arrival will be somewhat less depending on how quickly the original supersonic shock wave took to decay. But yeah, PhotonX's answer of about ten hours is probably about right.

Cheers!

Are you interested for real?

You can see that there have been many meteorites that hit the earth.

Meteors are objects that do NOT make it to the surface intact.

"100-1000 miles across" objects that "hit" the earth would cause a "shock wave" that would depend on the material that the objects were made of. as they hit the earth.

Shock waves go in all directions from the point of touch. The strait line, shortest distance to "the other side of the earth" is through the center of the earth.

The earth and all the other planets were pieces of the sun, in turn the sun and the stars of this local galaxy were pieces of the milky way's core,

Smaller objects leave their larger object because they repel each other. One of the reasons that they repel is that their lower layers NEAR their cores are the same. Positive to positive they repel. Repelling they leave. Each progressing away from each other. Each in its self is still decompressing atom by atom by fission. When the atoms of a planet or a star decompress to a level that they do not have a compressed core that is positive enough to attract electrons of the atoms around them then there is a further reason for the object to repel.

The decompressed material which was a planet or a star spreads apart. An example can be seen in the ort cloud of our sun.

Decompressed former planet and star material still exists and is influenced by the compressed objects around them.

Cores of galaxies last a long time. Cores of galaxies are very compressed and attract decompressed material.

Time does not mater at such great distances.

Eventually decompressed mater returns to one galactic core or another. Galactic cores compress the in coming material.

Compression reaches levels that there are enough positrons left behind toward the upper layers of the core, as the neutrons proceed further down, that areas of repulsion develop that exit the galactic core.

The exiting material is repelling from the galactic core and from its self. The material is also being influenced by the lower density of space, and the presence of those neutrons that were drawn out with the protons.

The exiting material can form up as huge stars, or as smaller objects such as stars like the sun, or smaller objects referred to as rubble.

The star's positive cores repel each other, while their negative surfaces repel negative surfaces, while negative surfaces attract positive cores.

Way back you were asking about a small meteor(ite) hitting a small planet. The shock wave would take a vary small time to reach the other side of the planet, only a rotation of the planet more or less.

I hope you are not to close in distance or time when such a "hit" occurs. It could hurt.

By the way, you can see the "hits" of such meteorites on Google Earth. One is located about 1000 miles off the eastern coast of the USA. The center of the "hit" is located at latitude 32°19'49.34"N, longitude 64°42'10.77"W, I am presently living on some of the crater edge of this crater called ELF 0001, You can see the crater edge by the mountains in a curved shape from far north of Allamuchy Township NJ to south of at least Jefferson National Forest - Woods, Eastern, WV 24941

Enjoy your thoughts.

Existence Life Form

Aubrey

ELF U MWGC Sol Earth 40d 54m 9.70s N 74d 50m 44.82s W MAH 2016 09 28 0138

No matter what the size, as long as it's big enough to create seismic disturbances on the other side of the planet, the seismic shock wave will arrive in around 41 minutes. The air blast is about 10 hours away. As far as the damage done by the impact, that all depends on approach speed, angle of impact, composition of the impactor, and the location and composition of the impact site. For something this big, it's pretty much a moot point. Of course, we'll never be struck by something this big. http://impact.ese.ic.ac.uk/ImpactEffects/

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Irrelevant. Had Apophis hit us, there wouldn't had been time to realize it, transmit messages long distance, and receive them globally prior to massive satellite disruption. This would leave only fiber optic lines to a small part of the earth capable of receiving and distributing the news. It would never be relayed quickly enough. Its akin the the tree falling in the woods. Does it make a sound?

Hours, before everything died.