Okay, I'm no astronomer or anything, I'm just wondering about an expression, 'cause there was some expression-explaining part of the site.

"Sucks worse than a black hole." Meaning: Something really really sucks.

I wonder, is this Good or Bad astronomy?

Well, black holes suck in the literal sense, and because of their powerful gravitational fields they're very good at sucking. In fact, they're probably better at sucking than everything else in the universe. So everything else in the universe sucks worse than a black hole ... so to answer your question ... err ... I don't know #-o

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lol wow. =D>

unless you get right next to the BH, it doesn't "suck" any more than a star or the earth does. Things orbit it just the same as they orbit everything else.

Now, when you get close things get a bit wierd, and you radiate away energy, and thus fall inexorably into the BH (unless something gives you more energy).

"sucks worse than a black hole" => "Does not suck as well as a black hole" So, if you assume a black hole to suck, and be the ultimate sucker, than yes, everything else sucks worse than a black hole.

On the other hand, if you want to think of "sucking" as being an atmospherical phenomenon due to a pressure differential, then, AFAIK, a black hole doesn't suck at all. Rather, things fall to a black hole like they fall to earth. Thus, a black hole doesn't suck at all, and so sucks at sucking. Sucks more than anything else at sucking, really. If that's the case, then the suckitude of something can never be greater than the suckitude of a black hole...

So, really, it's one of two extremes...

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That sucks

Well... Under normal conditions a black hole doesn't suck... Hmmm... But I guess it would suck if it came for a visit to earth...

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Only marginally connected to the topic, I know, but remember: The day Microsoft makes vacuum cleaners will be the day Microsoft makes a product that doesn't suck!

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A black hole does not suck at all. "Suck" means to apply a force to an object by reducing the air pressure over it.

But if the black hole were to pull in air on one side, then an object could be both pulled and sucked. In the mechanical sense of course. 8-[

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I've seen that before, it took a couple of reads, back then, for me to get it.

Actually, technically speaking, "suck" doesn't have any meaning. (just like decelerate isn't defined)

As Yoda might say, "There is no suck. There is only blow."

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Reminds of an another old line,
There is no gravity, the Earth sucks.

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Say what? Technically speaking, "suck" and "decelerate" are precisely defined. You could look it up.

Not as such. There is no need for decelerate since it's covered by acceleration, which is a vector. "Suck" isn't used because the force is exerted by particles at higher pressure, not by the lack of particles at lower pressure - a vacuum doesn't exert a force.

Just a couple of instances of physics definitions being different from lay definitions.

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"I have a cunning plan that cannot fail."
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I don't know about you, but I am off to take a cold shower.

Here are a couple of physics definitions for your perusal:

http://en.wikipedia.org/wiki/Acceleration

http://en.wikipedia.org/wiki/Sucking

Thank you. These prove my point quite nicely.

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Usually "sucking" is associated with fluids and pressures acting on fluids. In particular, when a vacuum is created (negative pressure). However, the current venacular tends to apply it to anything that is negative. I would say my math "sucks".

Pressure, however, is force over an area. Objects being pulled, or falling, into a black hole have a "force" acting upon them. Dividing the total force by the cross sectional area will give the average pressure acting on the object.

In the case of a black hole, another consideration should be noted. The extreme gravitational field causes the force (pressure) on the leading edge of the object to greatly exceed the trailing end of the object enough to rip the object apart (tidal stress). This really "sucks".

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

But the vacuum exerts no force on the object, which is why it's technically incorrect, from a physics standpoint.

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"I have a cunning plan that cannot fail."
S. Baldrick

True, however, it is the cause of the difference in pressure over a region. It would not be impropper to suggest that the wings of an airplane lift the plane due to the "sucking" action which occurs on top of the wings (which allows the net pressure difference to push the wings upward). No "sucking", no vacuum, no lifting, no flying and that would certianly "suck", even when it doesn't "suck".

I suppose what I am really saying is that the term "suck" or "sucking" has figurative meaning primarily and scientific meaning secondarily. It should not be considered a proper physics term. Maybe a physics hyperbole.

[Edit: I could be wrong as I am not a physicist nor scientist. I do own a physics book. :wink: ]

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.