Cosmology: Earth in goldylocks zone; dangerous (Introduction)

by David Turell , Friday, October 27, 2017, 01:11 (2373 days ago) @ David Turell

The recent neutron stars in collision point out how dangerous our universe really is. If such a collision occurred close to use the result is disastrous:

https://www.scientificamerican.com/article/a-nearby-neutron-star-collision-could-cause-...

"A kilonova, [two neutron stars colliding] however, has different physics at play. Neutron stars are a few dozen kilometers in radius rather than a few million like a typical stars. When these dense objects merge, they tend to produce jets that blast out gamma rays from their poles.

“'[W]hat it looks like to us, and the effect it has on us, would depend a lot on whether or not one of the jets was pointed directly at us,” Frank says. Based on its distance and orientation to Earth, a kilonova’s jets would walk the fine line between a spectacular light show and a catastrophic stripping away of the planet’s upper atmosphere. If a jet is pointed directly at us, drastic changes could be in store. And we probably wouldn’t see them coming. A kilonova begins with a burst of gamma rays—incredibly energetic photons that, by definition, move at light-speed, the fastest anything can travel through the universe. Because nothing else can move faster, those photons would strike first, and without warning.

“'What [the gamma rays] would do, probably more than anything else, is dissolve the ozone layer,” says Andrew Fruchter, a staff astronomer at the Space Telescope Science Institute. Next, the sky would go blindingly white as the visible light from the kilonova encountered our planet. Trailing far behind the light would be slower-moving material ejected from the kilonova—radioactive particles of heavy elements that, sandblasting the Earth in sufficient numbers, could still pack a lethal punch.

"That’s if the kilonova is close, though—within 50 light-years, give or take. At a safer distance, the gamma rays would still singe the ozone layer on the facing hemisphere, but the other side would be shielded by the planet’s bulk. “Most radiation happens very quickly, so half the Earth would be hidden,” Fruchter says. There would still be a momentarily blinding light. For a few weeks, a new star would burn bright in the sky before gradually fading back into obscurity.

"Don’t let all this keep you up at night. Kilonovae are relatively rare cosmic phenomena, estimated to occur just once every 10,000 years in a galaxy like the Milky Way. That’s because neutron stars, which are produced by supernovae, hardly ever form as pairs. Usually, a neutron star will receive a hefty “kick” from its formative supernova; sometimes these kicks are strong enough to eject a neutron star entirely from its galaxy to hurtle at high speeds indefinitely through the cosmos. “When neutron stars are born, they’re often high-velocity. For them to survive in a binary is nontrivial,” Fruchter says. And the chances of two finding each other and merging after forming independently are, for lack of a better term, astronomically low."

Comment: The universe is dangerous but we are in the goldilocks zone where little seems likely to happen. In answer to the inevitable question of why God might have allowed this danger, I will note that these explosions make the heavier elements like gold and on up to uranium in the periodic table. God obviously evolved the universe and the available elements in this way. We do not know, and will never know, whether He chose this method or it was the only way He could do it.