padowack:

Quote :

"why did you erase your part about the fog?"

ironic

8/23/2006 1:05:11 PM

Quote :

"A modified theory of gravity that incorporates quantum effects can explain a trio of puzzling astronomical observations – including the wayward motion of the Pioneer spacecraft in our solar system, new studies claim. The work appears to rule out the need to invoke dark matter or another alternative gravity theory called MOND (Modified Newtonian Dynamics). But other experts caution it has yet to pass the most crucial test – how to account for the afterglow of the big bang. Astronomers realised in the 1970s that the gravity of visible matter alone was not enough to prevent the fast-moving stars and gas in spiral galaxies from flying out into space. They attributed the extra pull to a mysterious substance called dark matter, which is now thought to outweigh normal matter in the universe by 6 to 1. But researchers still do not know what dark matter actually is, and some have come up with new theories of gravity to explain the galaxy observations. MOND, for example, holds that there are two forms of gravity. Above a certain acceleration, called a0, objects move according to the conventional form of gravity, whose effects weaken as two bodies move further apart in proportion to the square of distance. But below a0, objects are controlled by another type of gravity that fades more slowly, decreasing linearly with distance. But critics point out that MOND cannot explain the observed masses of clusters of galaxies without invoking dark matter, in the form of almost massless, known particles called neutrinos. Quantum fluctuations Now, Joel Brownstein and John Moffat, researchers at the Perimeter Institute for Theoretical Physics and the University of Waterloo in Ontario, Canada, say another modified gravity theory can account for both galaxies and galaxy clusters. The theory, called scalar-tensor-vector gravity (STVG), adds quantum effects to Einstein's theory of general relativity. As in other branches of physics, the theory says that quantum fluctuations can affect the force felt between interacting objects. In this case, a hypothetical particle called a graviton – which mediates gravity – appears in large numbers out of the vacuum of space in regions crowded with massive objects such as stars. "It's as if gravity is stronger" near the centres of galaxies, Brownstein told New Scientist. "Then, at a certain distance, the stars become sparse, and the gravitons don't contribute that much." So at larger distances, gravity returns to the behaviour described by Newton. Pioneer 10 anomaly Brownstein and Moffat tested the theory in several ways. They estimated that their gravitational change occurs 46,000 light years out from the centre of a large galaxy and half that distance for a small galaxy. They applied these estimates to 101 observed galaxies, and found that both their theory and MOND could account for their rotations. "The point is that neither of the two theories had any dark matter in them," says Brownstein. But the theories did diverge when the pair tested them against observations of 106 galaxy clusters. MOND could not reproduce the observed cluster masses but STVG accounted for more than half. Furthermore, the team tested the theory against observations of NASA's 34-year-old Pioneer 10 spacecraft, which appears about 400,000 kilometres away from its expected location in the outer solar system. Brownstein says the theory fits observations of the so-called Pioneer anomaly (see New Scientist feature, 13 things that do not make sense), while MOND cannot address it because Pioneer's acceleration is above a0. Big bang's afterglow "At three different distance scales, we see answers that agree with experiment," says Brownstein. "They are claiming they can solve all the world's problems," agrees Sean Carroll, a cosmologist at the University of Chicago in Illinois, US. But these experiments are "not what most cosmologists would first think of if they were going to test a new theory of gravity". He says any theory must also explain the development of large-scale structures in the universe, and most importantly, the afterglow of the big bang. Called the cosmic microwave background (CMB) radiation, this afterglow was produced about 370,000 years after the big bang when the first atoms formed and has been studied in great detail by satellites, such as NASA's WMAP probe. "The dark matter model is not perfect, but it made a very specific prediction for the microwave background that seems to be coming true, and it fits galaxies and clusters and large-scale structure and gravitational lensing," Carroll told New Scientist. "Nobody would be happier than me if it turned out to be modified gravity rather than dark matter, but it's becoming harder and harder to go along with that possibility." Brownstein says the team is currently testing its theories with work on CMB studies.""

8/23/2006 1:06:59 PM

My hidden variable is better than yours.

8/23/2006 1:13:14 PM

Quote :

"Ever see something at a distance, through fog, at dawn?"

Explains your reasoning exactly. You shouldn't make such comparisons, its grossly misleading. This is something scientists can't see. Gravity is not a good tool to use to observe something. It's evidence is circular. They are tryin to prove the existence of gravitational anomalies by finding more gravitational anomalies. Dosn't answer the question of what the anomaly is.


one more thing, models work perfectly. But they don't explain anomalies.

[Edited on August 23, 2006 at 1:23 PM. Reason : so easy]

8/23/2006 1:19:13 PM

So, obviously you're a big opponent of black holes.

8/23/2006 1:20:35 PM

why must you fight to get off topic? You know that this theory is unsupported. Yet you attempt to drag me into a debate about black holes?!?!

maybe another time sweetheart.


sarijoul as for you, you totally created a whole paragraph of stuff I never said. lol. wow

[Edited on August 23, 2006 at 1:26 PM. Reason : .]

8/23/2006 1:24:41 PM

Quote :

"padowack: why must you fight to get off topic?"

It's not much of a fight, and it isn't even off topic. But it was you who dragged us here.

I erased a question that poorly illustrated a point and posed a better one.

You implied I'd missed your point, and wholly ignored me when I asked you to elaborate on it. Instead you wanted to obsess over a bad question, which I even indulged you by reposting--though I had no intentions of using it to form an argument.

Then you let stupid like this into your post: "Gravity is not a good tool to use to observe something."

I pointed out that there are obviously phenomena within our universe that we primarily observe via gravitational effects, decidedly on topic.

So, this time I'll be more direct: DO YOU BELIEVE IN THE EXISTENCE OF BLACK HOLES?

Quote :

"padowack: You know that this theory is unsupported."

Actually, I think you're the only one in the entire thread who's made a claim this dumb. The theory is overwhelmingly supported, you obviously just lack the faintest idea what it actually claims.

[Edited on August 23, 2006 at 1:45 PM. Reason : .]

8/23/2006 1:43:21 PM

Quote :

"A modified theory of gravity that incorporates quantum effects can explain a trio of puzzling astronomical observations – including the wayward motion of the Pioneer spacecraft in our solar system, new studies claim. The work appears to rule out the need to invoke dark matter or another alternative gravity theory called MOND (Modified Newtonian Dynamics). But other experts caution it has yet to pass the most crucial test – how to account for the afterglow of the big bang. Astronomers realised in the 1970s that the gravity of visible matter alone was not enough to prevent the fast-moving stars and gas in spiral galaxies from flying out into space. They attributed the extra pull to a mysterious substance called dark matter, which is now thought to outweigh normal matter in the universe by 6 to 1. But researchers still do not know what dark matter actually is, and some have come up with new theories of gravity to explain the galaxy observations. MOND, for example, holds that there are two forms of gravity. Above a certain acceleration, called a0, objects move according to the conventional form of gravity, whose effects weaken as two bodies move further apart in proportion to the square of distance. But below a0, objects are controlled by another type of gravity that fades more slowly, decreasing linearly with distance. But critics point out that MOND cannot explain the observed masses of clusters of galaxies without invoking dark matter, in the form of almost massless, known particles called neutrinos. Quantum fluctuations Now, Joel Brownstein and John Moffat, researchers at the Perimeter Institute for Theoretical Physics and the University of Waterloo in Ontario, Canada, say another modified gravity theory can account for both galaxies and galaxy clusters. The theory, called scalar-tensor-vector gravity (STVG), adds quantum effects to Einstein's theory of general relativity. As in other branches of physics, the theory says that quantum fluctuations can affect the force felt between interacting objects. In this case, a hypothetical particle called a graviton – which mediates gravity – appears in large numbers out of the vacuum of space in regions crowded with massive objects such as stars. "It's as if gravity is stronger" near the centres of galaxies, Brownstein told New Scientist. "Then, at a certain distance, the stars become sparse, and the gravitons don't contribute that much." So at larger distances, gravity returns to the behaviour described by Newton. Pioneer 10 anomaly Brownstein and Moffat tested the theory in several ways. They estimated that their gravitational change occurs 46,000 light years out from the centre of a large galaxy and half that distance for a small galaxy. They applied these estimates to 101 observed galaxies, and found that both their theory and MOND could account for their rotations. "The point is that neither of the two theories had any dark matter in them," says Brownstein. But the theories did diverge when the pair tested them against observations of 106 galaxy clusters. MOND could not reproduce the observed cluster masses but STVG accounted for more than half. Furthermore, the team tested the theory against observations of NASA's 34-year-old Pioneer 10 spacecraft, which appears about 400,000 kilometres away from its expected location in the outer solar system. Brownstein says the theory fits observations of the so-called Pioneer anomaly (see New Scientist feature, 13 things that do not make sense), while MOND cannot address it because Pioneer's acceleration is above a0. Big bang's afterglow "At three different distance scales, we see answers that agree with experiment," says Brownstein. "They are claiming they can solve all the world's problems," agrees Sean Carroll, a cosmologist at the University of Chicago in Illinois, US. But these experiments are "not what most cosmologists would first think of if they were going to test a new theory of gravity". He says any theory must also explain the development of large-scale structures in the universe, and most importantly, the afterglow of the big bang. Called the cosmic microwave background (CMB) radiation, this afterglow was produced about 370,000 years after the big bang when the first atoms formed and has been studied in great detail by satellites, such as NASA's WMAP probe. "The dark matter model is not perfect, but it made a very specific prediction for the microwave background that seems to be coming true, and it fits galaxies and clusters and large-scale structure and gravitational lensing," Carroll told New Scientist. "Nobody would be happier than me if it turned out to be modified gravity rather than dark matter, but it's becoming harder and harder to go along with that possibility." Brownstein says the team is currently testing its theories with work on CMB studies.""

8/23/2006 1:50:59 PM

salisbury-ator

8/23/2006 1:52:50 PM

i'd stop posting it if you guys would stop arguing such a boring topic with that padowidiot

dark matter vs. modified newtonian theory is much more interesting than dark matter vs. nutjob

[Edited on August 23, 2006 at 1:54 PM. Reason : s]

8/23/2006 1:53:47 PM

Seems like the experiment leads to dark matter and away from alternative gravity. The two theories predict wildly different outcomes in the case of colliding galaxies. If the data didn't support dark matter theory's hypothesis, we'd be reading a different headline. The gravitational effects of seemingly "dark matter" didn't follow the mass, but stayed put.

8/23/2006 1:59:58 PM

What were you implying by this idiotic statement? Im still trying to figure that out!

Quote :

""Ever see something at a distance, through fog, at dawn?""

This illustrates that you have no real knowledge of or experience with astronomy and cosmology or anything remotely close. All you're doing is posting articles via google from individuals who you believe to have merit and support this theory through models and no empirical data Excoriator. There are just as many articles that counter this theory. Whats your drill?

My problem is with the dogmatic realism stressed by those who support this theory. Including you. On rational grounds, they are observing gravitational forces surrounding something(x) they believe to be there. They have no way to measure this "Dark Matter" or (x) itself. I know exactly what this article claims.

This is more of a philosophical matter than scientific one. Its going to take more than gravitonic evidence under certain circumstances to carry legitimate weight. You just can't claim something exists b/c you measured the material around it(x) via its gravitational force. There is no photonic evidence or anything else. So how can it be sooo strongly supported? Models? Please don't say models.

Quote :

"Actually, I think you're the only one in the entire thread who's made a claim this dumb. The theory is overwhelmingly supported, you obviously just lack the faintest idea what it actually claims."

Since the majority is allllllllways correct

[Edited on August 23, 2006 at 4:19 PM. Reason : you have nothing!!]

8/23/2006 4:01:50 PM

Whatever dude.

You win.

I'm an intellectual midget compared to you.

*bow*

[Edited on August 23, 2006 at 4:57 PM. Reason : always forget to bow...gotta remember that one]

8/23/2006 4:57:28 PM