# Tag Info

Accepted

### What is it exactly about these flares of infrared light from Sgr A* that "confirms" it is a supermassive black hole?

We have reasonably good measurements of the mass of Sagittarius A*, thanks to measurements of the movements of stars like S0-2 over several decades. It's been well-established that the mass of the ...
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### Did the earth form outside the solar system?

The chance happenstance that Earth happened to be floating along and got captured is minuscule. How did Earth wind up floating through space? There's no established mechanism for terrestrial planets ...
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### Did the earth form outside the solar system?

I think the Earth's orbit is by far the strongest argument you have that the Earth formed around the Sun. The orbit is nearly circular and almost in the Sun's equatorial plane, similar to the other ...
• 117k
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### How did they make a video of the center of the galaxy, and what is it exactly that's flashing there?

Question: How are these images obtained? Later in the video the narrator says they took the images using ESO's VLT. 03:40 [Narrator] 14.​ Making these measurements pushed the power of ESO’s Very ...
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### Why didn't all the iron and heavier elements find their way to the center of the accretion disc in the early solar system?

The process of differentiation is how metals like iron and nickel can become separated from less dense substances. It generally occurs in large, partly solid bodies in the early solar system, whose ...
• 117k
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### Quasar mass and accretion rates

Tricky to say for sure, but I would imagine it comes about from measurements of the luminosity and inference of the black hole mass in such systems. The most extreme objects radiate at the Eddington ...
• 117k
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### How do rocky objects between 1cm and 1m accrete to form planetesimals?

This is indeed a tricky problem, and the accretion of pebbles to form planetesimals is a big question in planetary science. You are right to say that small particles can stick together through ...
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### How much matter was ejected when the Solar System formed?

It is actually the other way around: First a massive accretion disc can form, through which material looses angular momentum and accretes onto the star radially, hence being angular momentum poor. ...