Posted on 04/01/2017 9:38:29 AM PDT by boycott
In case you haven't been paying attention, it has been a pretty exciting last few years for what astronomers call the "observable universe."
It's been a particularly rewarding stretch for Albert Einstein too, even though he died in 1955.
For instance, last year astrophysicists made the first observations of gravitational waves, which Einstein, exactly 100 years ago, predicted should exist. These waves, which I won't even try to explain, were observed when two black holes crashed into one another and merged. A black hole is formed from matter so dense, and with gravity so strong, that anything near it - even light -- is pulled into it, never to escape.
Black holes are the original invisibility cloaks. Because light cannot escape from them, they are impossible to see. We can only infer their existence because of the gravitational pull they exert on other celestial objects.
Black holes were predicted by Einstein's equations too.
Black holes are not the only invisible objects in the "observable" universe - not by a longshot. There is also dark matter. Like black holes, dark matter is invisible, but unlike black holes we have no idea where dark matter comes from. We know it is there the same way we know black holes are there -- by observing its gravitational effects on objects which we can see. Physicists think that there is about six times as much of this invisible dark matter in the universe as there is normal, visible matter like stars, planets, comets, asteroids, galaxies, and space debris from our dead satellites.
From now on, I think I'll call it the "so-called observable" universe.
Wait. It gets even stranger.
(Excerpt) Read more at al.com ...
If “dark matter” couples to gravitation, why don’t we see any evidence of their conglomerates crashing into other celestial bodies?
If “dark matter” couples to gravitation, why don’t we see any evidence of their conglomerates crashing into other celestial bodies?
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Good question. I can’t answer that one.
As the physicist Niels Bohr famously said, “If you aren’t completely confused... you haven’t understood it.”
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That’s how I understand it.
Well, the universe is so vast, maybe it's like dropping a rock into the ocean a hundred miles out. The splash is immediate and if we're present, we can see it. But it's effects, the ripples, die out long before it reaches our shore............
That's the best I can come up with...
Sort of the “un”iverse instead of the “uni”verse.
Visible normal matter and invisible dark matter respond to gravity in a similar way, forming clouds of stars, the galaxies. The first tip-off was that for the amount of matter seen through a telescope, the implied mass seen should have a certain rate of spin. The galaxies actually were turning much too fast, which was only possible if they had an unseen component adding extra heft.
The dark matter and normal matter interact through gravitational attraction, so a grouping of the two tend to approach an average velocity when intermixed. A missing component for dark matter is the lack of interaction with light, thus no photon acceleration of matter as with a solar sail. Based on that difference, the dark matter will always find a path which deviates somewhat from the normal matter grouping. Other properties may apply such as carrying a static charge or self repulsion? May not stick together to build large bodies; but, still has a gravitation component.
Another observation is the bending of light from distant galaxies by something invisible in the foreground. Sometimes a duplicate image of the distant galaxy is visible offset from the primary location, or a distorted ring of light is present, with the observed galaxy at the bulls-eye. Gravity warps space—bends light, therefore has an effect like an optical lens to form, or sometimes distort an image.
This will have to be my disclaimer:
As the physicist Niels Bohr famously said, “If you aren’t completely confused... you haven’t understood it.”
Well, the universe is so vast, maybe it's like dropping a rock into the ocean a hundred miles out. The splash is immediate and if we're present, we can see it. But it's effects, the ripples, die out long before it reaches our shore............
That's the best I can come up with...
YEP, Two black holes make a really, really big wave. Hillary Clinton crashing into a black hole, that is not so big that it can be detected millions of light-years away..
Fascinating!
Let's take a look inside Uranus.
SNOLAB: Doing Science in an Active Mine
I'm a genius!
The “Big Freeze” theory needs to explain what will become of black holes. If all matter expands to the point where even the smallest particles are widely separated those black holes which have sucked up enormous volumes of matter, to the point where the gravitational pull allows nothing to escape, must have to come apart to allow that matter to scatter.
Also, perhaps black holes, which didn’t exist until the time had passed for large stars to form, live their lives and then explode, are the generators of dark energy which is also a late comer to the universe. As time passes more black holes are formed which coincides with the increase in dark energy.
Just a couple of thoughts.
If “dark matter” couples to gravitation, why don’t we see any evidence of their conglomerates crashing into other celestial bodies?
...
Since dark matter doesn’t interact with electromagnetism, it conglomerated on a much larger scale such as that for galaxies and galaxy clusters.
Stars and planets can pass right through it because it doesn’t interact with visible matter via electromagnetism, and the gravitational effect of dark matter is pretty much the same from one end of the Solar System to the other, so no gravitational force due to dark matter is noticeable on our scale.
Yet electromagnetism is also gravitationally effected, such as in gravitational lensing of distant galaxies.
Ugh. Too much theory. It’s making me crazy.
You did ask a very good question.
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