A Quote by Andrea M. Ghez

The key to proving that there's a black hole is showing that there's a tremendous amount of mass in a very small volume. And you can do that with the motions of stars. The way the star moves around the center of the galaxy is very much like the way the planets orbit the sun.
The key to proving that there's a black hole is showing that there's a tremendous amount of mass in a very small volume. And you can do that with the motions of stars.
Proof of the black hole is a tremendous amount of mass inside a very small volume. There's 4 million times the mass of our sun within a region that's comparable to the size of our solar system.
If you want to see a black hole tonight, tonight just look in the direction of Sagittarius, the constellation. That's the center of the Milky Way Galaxy and there's a raging black hole at the very center of that constellation that holds the galaxy together.
Black holes are very exotic objects. Technically, a black hole puts a huge amount of mass inside of zero volume. So our understanding of the center of black holes doesn't make sense, which is a big clue to physicists that we don't have our physics quite right.
But what exceeds all wonders, I have discovered four new planets and observed their proper and particular motions, different among themselves and from the motions of all the other stars; and these new planets move about another very large star [Jupiter] like Venus and Mercury, and perchance the other known planets, move about the Sun. As soon as this tract, which I shall send to all the philosophers and mathematicians as an announcement, is finished, I shall send a copy to the Most Serene Grand Duke, together with an excellent spyglass, so that he can verify all these truths.
We have this interesting problem with black holes. What is a black hole? It is a region of space where you have mass that's confined to zero volume, which means that the density is infinitely large, which means we have no way of describing, really, what a black hole is!
One of the big mysteries about the black hole at the center of the galaxy is, 'Why don't we see emission from matter falling onto the black hole, or, rather, the black hole eating up its surroundings?'
There's a large cluster of stars that are orbiting the center of our galaxy. And by measuring the motion of stars, and in particular, their orbits, we can figure out whether or not there's a central black hole.
Data suggest that central black holes might play an important role in adjusting how many stars form in the galaxies they inhabit. For one thing, the energy produced when matter falls into the black hole may heat up the surrounding gas at the center of the galaxy, thus preventing cooling and halting star formation.
This is the very center of everything there is. A huge black hole eating up the galaxy. The end of everything.
In less than a hundred years, we have found a new way to think of ourselves. From sitting at the center of the universe, we now find ourselves orbiting an average-sized sun, which is just one of millions of stars in our own Milky Way galaxy.
If we're thinking about old civilizations, those that formed a long time ago and there were stars and planets around long before Earth even existed, then these are going to be towards the center of the galaxy. That is the place to look if you think there are ancient civilizations that have made beacons or some other way of attracting our attention.
One in 200 stars has habitable Earth-like planets surrounding it - in the galaxy, half a billion stars have Earth-like planets going around them - that's huge, half a billion. So when we look at the night sky, it makes sense that someone is looking back at us.
But there's always a Mass. It's not a formal Mass at all. We're sitting around her dining room table with wine and Eucharist and holding hands. It's very informal and small, but to me that's a wonderful way to have Mass.
Earlier generations of stars in the galaxy could well have had planets. But really, there was only hydrogen and helium to work with, so they'd all be gas giants and not small, rocky planets.
Venus and Mars are our next of kin: they are the two most Earth-like planets that we know about. They're the only two other very Earth-like planets in our solar system, meaning they orbit close to the sun; they have rocky surfaces and thin atmospheres.
This site uses cookies to ensure you get the best experience. More info...
Got it!