Odyssée (épistémologique) à travers la physique en train de se [dé, re] construire, dans {dans sur} un océan de données contradictoires d'informations numérisées.
[A new exciting, another boring usual] astrophysical event?
The discovery, announced Monday at a news conference and in scientific reports written by some 3,500 researchers, solves a long-standing mystery about the origin of these heavy elements — which are found in everything from wedding rings to cellphones to nuclear weapons.
It's also a dramatic demonstration of how astrophysics is being transformed by humanity's newfound ability to detect gravitational waves, ripples in the fabric of space-time that are created when massive objects spin around each other and finally collide.
"It's so beautiful. It's so beautiful it makes me want to cry. It's the fulfillment of dozens, hundreds, thousands of people's efforts, but it's also the fulfillment of an idea suddenly becoming real," says Peter Saulson of Syracuse University, who has spent more than three decades working on the detection of gravitational waves...
What all the images showed was a brand-new point of light that started out blueish and then faded to red. This didn't completely match what theorists thought colliding neutron stars should look like — but it was all close enough that Daniel Kasen, a theoretical astrophysicist at the University of California, Berkeley, found the whole experience a little weird.
"Even though this was an event that had never been seen before in human history, what it looked like was deeply familiar because it resembled very closely the predictions we had been making," Kasen says. "Before these observations, what happened when two neutron stars merged was basically just a figment of theorists' imaginations and their computer simulations."
He spent late nights watching the data come in and says the colliding stars spewed out a big cloud of debris.
"That debris is strange stuff. It's gold and platinum, but it's mixed in with what you'd call just regular radioactive waste, and there's this big radioactive waste cloud that just starts mushrooming out from the merger site," Kasen says. "It starts out small, about the size of a small city, but it's moving so fast — a few tenths of the speed of light — that after a day it's a cloud the size of the solar system."
According to his estimates, this neutron star collision produced around 200 Earth masses of pure gold, and maybe 500 Earth masses of platinum. "It's a ridiculously huge amount on human scales," Kasen says...
The merger was detected for more than a full minute… to be compared with black holes whose mergers can be detected for less than a second. It’s not exactly clear yet what happened at the end, however! Did the merged neutron stars form a black hole or a neutron star? The jury is out.
If there’s anything disappointing about this news, it’s this: almost everything that was observed by all these different experiments was predicted in advance. Sometimes it’s more important and useful when some of your predictions fail completely, because then you realize how much you have to learn. Apparently our understanding of gravity, of neutron stars, and of their mergers, and of all sorts of sources of electromagnetic radiation that are produced in those merges, is even better than we might have thought. But fortunately there are a few new puzzles. The X-rays were late; the gamma rays were dim…
