4 ms·
1. 5 solar masses is 1x10^34 g. 1 g of mass is roughly 0.9x10^14 J (mc^2). So, roughly 1x10^48 J. 1 ly is roughly 1x10^16 m. Surface area of a sphere with r=
by drran 5y ago
1.
5 solar masses is 1x10^34 g.
1 g of mass is roughly 0.9x10^14 J (mc^2).
So, roughly 1x10^48 J.
1 ly is roughly 1x10^16 m. Surface area of a sphere with r=1 ly, is 4πr^2 = 4π x 10^32 m^2 or roughly 1x10^33, so each m^2 of surface will receive 1x10^48/1x10^33 = 10^15 Watt, or about 10^12 x brighter than our Sun on Earth in sunny day, but for 1 second only.
2. Spacetime is 4d array: [x,y,z;t]. Warping of spacetime means that a scientist applies a mathematical formula to the array directly, like shader in OpenGL. It has no physical meaning. It just a quick way to simulate unknown physical process, to make a prediction.
3. No, it doesn't. Our local group of galaxies is expanding, but this is a coincidence. Actually, we are falling into a black hole. Nearest big black hole is in the center of our galaxy, then Great Attractor, then Shapley Attractor.
- hypertele-Xii 5y ago> about 100x brighter than our Sun on Earth in sunny day, but for 1 second only. Sounds hot. Flash burn everything not made of stone. Land life wouldn't survive?
- drran 5y agoI made a mistake in the calculation (10^34 x 10^14 is 10^48, not 10^38), so it's 10^12 brighter. Nobody will survive on the lit surface of a planet.
- phasetransition 5y agoSo 1e6 light year radius to match the solar irradiance from purely inverse square losses? Wow.
- x3n0ph3n3 5y agoAnd it would likely ignite the atmosphere, which would travel at the speed of sound to the "dark" side of the planet, yes?
- ben_w 5y agoIt would have that effect if the energy was in the form of photons, but it is gravity waves. If you release 5 solar masses of energy in one second, electromagnetically and with the same spectrum as the sun, half way between the Milky Way and Andromeda, every star in both galaxies would see it only a little dimmer as Sol appears on Mars. https://www.wolframalpha.com/input/?i=%28%28%285+solar+mass%29*c%5E2%29%2F%281+second%29%29+%2F+%284π%281.287e6+ly%29%5E2%29 https://www.wolframalpha.com/input/?i=%28%28%285+solar+mass%...
- phasetransition 5y agoWhat determines whether the merger is non-radiative in the EM? Why was the collision of two neutron stars radiative? It seems like the universe would be immeasurably more dangerous than it already is, if all of these events were primarily EM radiative in nature. As a non-physicist, I'm also curious how gravity is simultaneously so much weaker than the other forces, but yet spacetime seems to be able to stably survive these immense releases of energy.
- nine_k 5y ago1. I suppose 10^12 brighter than the Sun for 1 second is like standing right next to a large nuclear blast, or a series of them to extend the irradiation phase to 1 second. It would take less than 1 second for an observer to evaporate, but the time is important to see if e.g. the surface of the planet would turn to cinder and glass. 2. I suppose it's still possible to illustrate. We can imagine that the spacetime gets "bulged" a bit, so light rays become slightly bent when passing it. It's likely impossible to notice with a naked eye from inside without being torn by tidal forces. But it's quite visible from some distance: pictures of gravitational lensing on astronomical scale are easy to find.