I just read something amazing, is it true that a black hole is a million times bigger than our Sun?

Question

I'm dumb, lol.

Answer 1

Not bigger in size but bigger in mass, their gravity is nearly unlimited.

Answer 2

There are several types of black holes:

1. Formed from stars that are at least 3 to 4 times more massive than the sun. When such a star turns into a black hole, the event horizon (point of no return, after which even light cannot escape the gravitational field) is approx. the size of the original star from which the black hole formed. The black hole itself is supposed to be matter compressed to infinity, and though it is much smaller than the star from which it formed, nobody has measured its actual size.

2. Very massive stars form enormous black holes, sometimes several such merge (have a look at what happens when galaxies collide and their central black hole(s) merge) to form a super massive black hole). The have gigantic event horizons, however the density of such black holes may actually be quite low (since volume is proportional to cube of the radius which increases more rapidly, whereas mass increases linearly, and density is inversely proportional to volume). Thus such a black hole may appear to be a million or even trillion times larger than it actually is.

3. Quasars are supposed to be powered by supermassive black holes: surprisingly, they must be having an colossal radius to be able to generate so much of energy (and luminosity) and may require to devour between 10 to thousands of suns each year (think of what they have been doing for billions of years, for what we see of them is at least a few billion years old - the time taken for light to reach us now, after covering such a vast distance :-)

So if the earth were to turn into a black hole, it would require to fit (all the mass i.e.) into a sphere of a diameter of a few millimeter. However, the surface (where we now stand) would be the event horizon. Beyond this, any spaceship would need the present escape velocity (11.2 kmps) to go into space, but once it reaches what is now the surface of the earth, not even light will escape it... So to a distant observer, the size of earth as a black hole would appear to be the same size as the earth is now, though in reality the actual black hole is only mm in diameter!

Aren’t we happy that the earth is not a black hole?

Andrew

Answer 3

"bigger" is a vague term. A black hole is a million times more massive than our sun, but in terms of physical size there's some debate as to what define's the black hole's size.

Within each black hole is a hypothetical point of mass called a singularity. This is theorized to be as small as an atom.

Each black hole is also characterized by it's boundry in space where once you're in it's gravitational pull you can't escape. This boundry is called the event horizon and it is theorized to be millions of times the radius of the sun.

Black Holes are largely hypothetical in nature, so there are no wrong answers, but the size of the black hole is kind of dependent of whether you're refering to the event horizon or the singularity.

Answer 4

A black hole's size is ZERO. It is a single point (a singularity) with a mass several times greater than our Sun.

Very near the black hole, the gravity may be millions of times bigger than the gravity very near the Sun, but a black hole is never anything but a point mass.

Answer 5

Well, I think that you may be referring to the expanse of the Event Horizon on a Black hole, that can be several times larger than our sun. The center of the Black Hole which is known as a "singularity" is the smallest thing in the Universe, not much is known of what happens inside black Holes.

Answer 6

Depends what your definition of "bigger".
Black holes are theorized to exist that are as small in diameter as an atom or as large in diameter as our entire solar system.
If you mean bigger in mass, the accepted theory is that generally black holes start when stars of masses at least 8 times collapse at the end of their lives.
But the mass doesn't stop there - there are black holes believed to exist in the centres of most medium and large galaxies that are called "supermassive black holes", with masses of a million times our sun and more.

Answer 7

Black holes are about as big as a period on a page. However, the stars it takes to make them have to be tens or hundreds of times larger than our Sun. I think that's what you misunderstood.

Also, the black hole believed to be at the center of the galaxy is supposedly around that size... is that what you're talking about?

Answer 8

Bigger? No. Black holes are smaller than the Earth. However, they can be many times as massive as the Sun.

Answer 9

Yes that is true. I took Stellar and Galactic Astronomy last semester and got an A. I remember learning about that.

Answer 10

Probably. Keep in mind that our interpretations of things like size and time are relative to our size and our time.