From Newsgroup: alt.fan.heinlein

"a425couple" wrote in message news:8Vd9Q.130103$KxI2.107112@fx45.iad...

In the next week or two I hope to visit with my oldest grandchild, age
13, who lives out of state. She has started reading sci-fi, and I will
give her a copy of Arthur C. Clarkes "Rendezvous with Rama."

[ I wouldn't have flunked the test. ]

from https://www.iflscience.com/we-may-have-our-third-interstellar-visitor-and-its-nothing-like-the-previous-two-79837

...Annoyingly, however, the
closest approach will occur when Earth is worst positioned to see it, on
the opposite side of the Sun.
------------------------------
That's good, Earth will present the sunlit side and not have to turn off all lights at night to hide.

An object is known to be from beyond the solar system if its orbit is hyperbolic or it exceeds solar escape velocity, 42.1 km/s at our orbital distance and decreasing as it moves outward. Isaac Newton determined this. https://www.gutenberg.org/ebooks/76404

Star or planet gravity is a free way to navigate in space: https://en.wikipedia.org/wiki/Gravity_assist

Like a brick through a window.
https://en.wikipedia.org/wiki/Oh-My-God_particle

For comparison an electron - positron annihilation releases two oppositely directed gamma rays of 0.511 MeV each, and it's 1862MeV or 3x10-10 Joules
for a proton - antiproton collision. 1 Joule is 1 Watt-Second.

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