Black Holes - how fast do they suck things in?

Conro · Post by **Conro** » Mon Jun 02, 2008 1:11 am

what i don't get, and mind you i'm still in high school so i don't know everything, is if gravity pulls matter, or mass, doesn't that mean that light has mass or is matter because a black hole can capture it?

jesusfreak16 · Post by **jesusfreak16** » Mon Jun 02, 2008 2:47 am

good question

Nereid · Post by **Nereid** » Tue Jun 03, 2008 1:33 am

Conro wrote:what i don't get, and mind you i'm still in high school so i don't know everything, is if gravity pulls matter, or mass, doesn't that mean that light has mass or is matter because a black hole can capture it?

You've probably heard of the famous E = mc^2 {that's 'squared'), which expresses in an equation the equivalence of mass and energy.

In Einstein's theory of General Relativity (GR), mass and energy are indeed equivalent, so far as gravity is concerned; they are 'mass-energy'.

Light certainly has energy! The energy of a photon (the 'fundamental particle' of light), of frequency ν (that's supposed to be the Greek letter 'nu', which is the symbol commonly used for 'frequency'), is hν ('h' is a special constant in physics). One easy way to understand that light (or electromagnetic radiation) has energy is to stand in the midday sun ... depending on the time of year and your latitude, you will soon get hot, and also get suntanned (or burned) ... the energy of light (infrared, ultraviolet) from the Sun. Also, if you put something in a microwave and turn it on, it will get hot (i.e. energy transferred to your food (say) from the microwave photons).

One strange thing about GR is that it says gravity is not a force, but is geometry ... the curvature of space-time. And the amount that space-time is curved by is determined by the amount of mass-energy 'there'. Near a black hole, space-time is curved very strongly ...

makc · Post by **makc** » Fri Jun 06, 2008 8:18 pm

Nereid for some reason you sound like Harry

Btw, your next post will be #666

Nereid · Post by **Nereid** » Fri Jun 06, 2008 9:03 pm

makc wrote:Nereid for some reason you sound like Harry Btw, your next post will be #666

I do?

Is there some way to relate 666 (or any other 3-digit number) to pi? to e?

Or some dimensionless physical constant, like the fine-structure constant?

Not exactly of course, because they are all irrational numbers (as far as we know, for the physical ones), and there is no number system in which irrational numbers are integers (at least, as far as I know ...).

harry · Post by **harry** » Fri Jun 06, 2008 11:19 pm

G'day

God for sake,,,,,,,,,,,,,,,,,,,,no way man

BMAONE23 · Post by **BMAONE23** » Sat Jun 07, 2008 3:12 am

Nereid wrote:
makc wrote:Nereid for some reason you sound like Harry Btw, your next post will be #666
I do?

Is there some way to relate 666 (or any other 3-digit number) to pi? to e?

(snip)

As a matter of fact there is a 3 digit number that you can relate to pi..(dare I) 3.14

harry · Post by **harry** » Sat Jun 07, 2008 4:53 am

G'day

Hey!!!!!!!!!!!!

That "I Do" words got me in problems for over 30 years.

Its like a pi in the sky and its eeeeeeeery.

That 666 reminds me of the other number, 2 digits.

Orca · Post by **Orca** » Sat Jun 07, 2008 12:30 pm

Question 1: Nerd alert! To how many decimal places can you recite pi?

I have it up to 3.141592654 <- with the 3 rounded up, it ends "6, 5, 4"

Question 2: I have heard people pronounce phi ( Φ ) as "fee" rather than "fi." If "fee" is correct, shouldn't we pronounce pi as "pee?"

Imagine the terrible jokes that would ensue. "Man, I have to take a pee R squared."

harry · Post by **harry** » Sat Jun 07, 2008 1:13 pm

Hello Orca

You said

Question 2: I have heard people pronounce phi ( Φ ) as "fee" rather than "fi." If "fee" is correct, shouldn't we pronounce pi as "pee?"

That is quite close. That is how the Greeks pronounce their letters. The English take other's letters and numbers and pronounse them as they wish.

That's life.

Orca · Post by **Orca** » Sun Jun 08, 2008 10:27 pm

harry wrote:
The English take other's letters and numbers and pronounse them as they wish.

From A to Zed...that's because they have English accents! Everyone has an accent of some sort; except of course the folks on the West Coast of the United States. Only place in the world without accents.

BMAONE23 · Post by **BMAONE23** » Mon Jun 09, 2008 5:03 am

Orca wrote:
harry wrote:
The English take other's letters and numbers and pronounse them as they wish.

From A to Zed...that's because they have English accents! Everyone has an accent of some sort; except of course the folks on the West Coast of the United States. Only place in the world without accents.

That is because of the price of gas...we can't afford accents

harry · Post by **harry** » Mon Jun 09, 2008 5:53 am

G'day from the land of ozzzz

On the West coast do they have cars and electricity.

Or just on the East coast.

BMAONE23 · Post by **BMAONE23** » Mon Jun 09, 2008 7:05 pm

On the west coast, We do have cars and electricity but these luxuries take all of our surplus cash so we can't afford to have accents.

Conro · Post by **Conro** » Mon Jun 23, 2008 4:48 pm

[quote="Nereid"][quote="Conro"]what i don't get, and mind you i'm still in high school so i don't know everything, is if gravity pulls matter, or mass, doesn't that mean that light has mass or is matter because a black hole can capture it?[/quote]You've probably heard of the famous E = mc^2 {that's 'squared'), which expresses in an equation the equivalence of mass and energy.

In Einstein's theory of General Relativity (GR), mass and energy are indeed equivalent, so far as gravity is concerned; they are 'mass-energy'.

Light certainly has energy! The energy of a photon (the 'fundamental particle' of light), of frequency ν (that's supposed to be the Greek letter 'nu', which is the symbol commonly used for 'frequency'), is hν ('h' is a special constant in physics). One easy way to understand that light (or electromagnetic radiation) has energy is to stand in the midday sun ... depending on the time of year and your latitude, you will soon get hot, and also get suntanned (or burned) ... the energy of light (infrared, ultraviolet) from the Sun. Also, if you put something in a microwave and turn it on, it will get hot (i.e. energy transferred to your food (say) from the microwave photons).

One strange thing about GR is that it says gravity is not a force, but is geometry ... the curvature of space-time. And the amount that space-time is curved by is determined by the amount of mass-energy 'there'. Near a black hole, space-time is curved very strongly ...[/quote]

so what your saying is that black holes' curvature of space time is so extreme that mass-energy is captured? That makes sense. You did a much better job explaining than my science teacher

Another question though. I was thinking the other day, does density apply in space because if it does doesnt that mean that since a black hole is infinitely dense, then that means that space has a density greater than 0 or is also infinitely dense because the definition of a black hole is that it is so dense that it creates a rip in space-time. and if we found out the density of space, wouldn't it be possible to send stuff into some sort of other space where laws would be different than they are in this space, and use this for some sort of interstellar travel

Starship Asterisk*

Black Holes - how fast do they suck things in?

idk

Re: idk

Re: idk