With reference to space. Can some of these areas be interconnected.
Does dark matter allow the conduction of sound waves?
i don’t think sound would work since there would be no air particles in dark matter.
http://Cosmology.com Dark Matter Dark Energy & the Unknown Universe, by Rhawn Joseph, Ph.D.
Duration : 0:5:6
What do you think dark matter really is?
Why do you think it is important?
And does it REALLY matter?
Is that so, cosmo?
Then you can tell me what you think it is and why it we wouldn’t exist without it.
I assume you know exactly what it is after spending half your life studying?
Or have you no real answer?
I like how you stated your question – very clever!
First – what is dark matter. Dark matter is dark because it is unseen and because it is unknown or more importantly unexplained. Lord Kelvin in the 19th Century estimated that if the Sun burned do to chemical reactions it would burn out in 30,000 years. But as it was discovered that the earth had a history much older than that, there must be something else that fuels the Sun and stars. It was not until nuclear energy was discovered and investigated in the 20th Century that we understood what happens within a star like the Sun.
Dark matter represents a similar mystery. If galaxies represent all the matter that matters, then as Zwicky first discovered we would expect a drop off in the velocities of stars as they orbit further from the center of the galaxy. Instead, Zwicky saw that galaxies have rotation curves as though they were orders of magnitude greater than what we see. The same holds for galaxy clusters of all sizes. So a mystery.
The other part of darkness – unseen – comes from the fact if we have unseen matter all over the place but yet can see back to the beginning of the universe, then the dark matter cannot interact strongly with light. Call that our first clue.
As to the second part of your question. It matters only if faced with a mystery you must find an answer. Of course it would be difficult to accept any of our current physical theories if they cannot explain this mystery, and in turn the validity of any scientific pursuit if mysteries as fundamental as where is matter can be left unanswered. Whether or not it is a big deal once the answer is found – don’t know, but maybe.
The Mystery of Dark Matter (1/4): Stars Are Moving Too Fast.
A mystery exists! Galaxies do not seem to have enough mass for stars to orbit at their observed speeds. Galaxies should be flying apart, but they don’t. Why not? Explore the surreal world of dark matter – one of the universe’s greatest mysteries.
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Shedding Light on Dark Matter
Over the last few decades, physicists have discovered that around ninety percent of every galaxy in the universe is made of an unseen substance called dark matter. Damian Pope, PIs Senior Manager of Scientific Outreach, comments, Its currently one of the hottest topics in physics. The module provides teachers with tools to show how dark matter was discovered, to explain why it remains a mystery, and to share the passion of scientists who are trying to discover what its made of.
This presentation is available to educators on DVD and comes complete with specially-crafted teacher notes.
• http://www.perimeterinstitute.ca
The Mystery of Dark Matter Video Game
• http://perimeterinstitute.ca/dark_matter_game/index.html
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In astronomy and cosmology, dark matter is a form of matter that is undetectable by its emitted electromagnetic radiation, but whose presence can be inferred from gravitational effects on visible matter and background radiation. According to present observations of structures larger than galaxies, as well as Big Bang cosmology, dark matter accounts for the vast majority of the mass in the observable universe.
Dark matter was postulated by Fritz Zwicky in 1934, to account for evidence of “missing mass” in the orbital velocities of galaxies in clusters. Subsequent to then, other observations have indicated the presence of dark matter in the universe, including the rotational speeds of galaxies, gravitational lensing of background objects by galaxy clusters such as the Bullet Cluster, and the temperature distribution of hot gas in galaxies and clusters of galaxies.
Dark matter plays a central role in state-of-the-art modeling of structure formation and galaxy evolution, and has measurable effects on the anisotropies observed in the cosmic microwave background. All these lines of evidence suggest that galaxies, clusters of galaxies, and the universe as a whole contain far more matter than that which interacts with electromagnetic radiation: the remainder is frequently called the “dark matter component,” even though there is a small amount of baryonic dark matter. The largest part of dark matter, which does not interact with electromagnetic radiation, is not only “dark” but also, by definition, utterly transparent.
The vast majority of the dark matter in the universe is believed to be nonbaryonic, which means that it contains no atoms and that it does not interact with ordinary matter via electromagnetic forces. The nonbaryonic dark matter includes neutrinos, and possibly hypothetical entities such as axions, or supersymmetric particles. Unlike baryonic dark matter, nonbaryonic dark matter does not contribute to the formation of the elements in the early universe (“big bang nucleosynthesis”) and so its presence is revealed only via its gravitational attraction. In addition, if the particles of which it is composed are supersymmetric, they can undergo annihilation interactions with themselves resulting in observable by-products such as photons and neutrinos (“indirect detection”).
Nonbaryonic dark matter is classified in terms of the mass of the particle(s) that is assumed to make it up, and/or the typical velocity dispersion of those particles (since more massive particles move more slowly). There are three prominent hypotheses on nonbaryonic dark matter, called Hot Dark Matter (HDM), Warm Dark Matter (WDM), and Cold Dark Matter (CDM); some combination of these is also possible. The most widely discussed models for nonbaryonic dark matter are based on the Cold Dark Matter hypothesis, and the corresponding particle is most commonly assumed to be a neutralino. Hot dark matter might consist of (massive) neutrinos. Cold dark matter would lead to a “bottom-up” formation of structure in the universe while hot dark matter would result in a “top-down” formation scenario.
As important as dark matter is believed to be in the universe, direct evidence of its existence and a concrete understanding of its nature have remained elusive. Though the theory of dark matter remains the most widely accepted theory to explain the anomalies in observed galactic rotation, some alternative theories such as modified Newtonian dynamics and tensor-vector-scalar gravity have been proposed. None of these alternatives, however, has garnered equally widespread support in the scientific community.
• http://en.wikipedia.org/wiki/Dark_matter
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Duration : 0:6:10
From what I understand, dark energy is the empty space in between stars and planets, and the cosmological constant is the anti-gravitational energy that expands the universe.
What is dark matter?
Ok you seem to be close but not quite spot on. Bear with me please.
The Cosmological Constant was a term coined by Einstein in order to explain why the universe was stable, and didn’t either fly apart due to not enough gravity, or collapse due to to much matter. It was basically Einsteins way of shrugging his shoulders and saying he didn’t have an answer. When the question was posed he merely stated that there must be some sort of mysterious energy or matter between the galaxies that maintained balance he called this the cosmological constant.
This was of course decades ago when physicists believed we lived in a static Universe that neither expanded nor contracted. At least until edwin hubble came along. Hubble’s red shift observations showed that the Universe wasn’t constant at all and was in fact expanding. One of the first people he told about what he saw was none other than Albert Einstein, who after agreeing with Hubble called the concept of a cosmological constant his "greatest blunder" and let the idea go.
Interestingly enough, by mere chance Einstein may actually have been on to something, because these days, we have some theories that are very similar to the cosmological constant, and just as mysterious. Nowadays e have split the CC into to separate parts. Dark Matter, and Dark Energy.
Now, on to dark Matter. Observations using our best theory of gravity, (relativity) seem to show that there isn’t actually enough matter in galaxies to keep them together.
Think of our galaxy as a handful of sand thrown through the air. The sand would scatter rapidly as the tiny grains don’t have enough gravity to hold themselves together. Like sand, all of the stars in our galaxy should actually fly apart at tremendous speeds… but they don’t. So either Einstein (and newton) are wrong about gravity, which doesn’t seem to be the case, (although it very well might be) or we are somehow not seeing about 95% of the matter and energy in our universe. The missing matter is called dark matter. As of right now it’s just as mysterious as it sounds, no one has ever seen it, and nobody has any idea how to find it. The only reason we know it’s there is because all of the galaxies in the universe aren’t flinging themselves apart. The Universe acts like dark matter is there… so we believe it is there even though it is effectively invisible to us.
Now, as for dark energy. When I said that 95% of the universe was missing, I didn’t just mean matter. Dark Matter probably accounts for about 25% of the missing universe… The rest is something even more mysterious. Dark energy.
Hubble was the first to notice that the universe was expanding, an impressive feat given the old technology he had to work with, but today’s tech is exponentially more accurate, and using modern Instruments we have actually found that the universe is not only expanding, but that expansion is actually accelerating.
This seems to go against the very foundation of physics. Things don’t just accelerate out of nowhere. In order for something to accelerate there needs to be some sort of energy pushing it, and in order for the galaxies to be expanding at the rate they are requires a staggering amount of energy, so staggering in fact that our math tells us that about 70% of the universe must be made of this energy…. but like dark matter we cannot detect anything pushing the galaxies apart. Hence the term, Dark Energy.
I Apologize for the length of my answer… but lengthy as it is, this has only been a very basic over cap… there is bunches that I haven’t covered… But I think this should be enough to satisfy your curiosity.
When a star explodes into a supernova does it trap dark matter inside of the newly formed singularity or does the supernova tself create dark matter? Due to the intense gravity it is unable to escape.
Also does a blackhole suck in dark matter and maybe that dark matter would accumulate on or in the singularity…
Is dark matter stuck inside of a neutron star?
1. > Supernova explodes creates a powerful explosion of hydrogen. When it explodes its velocity about 1/10 c (velocity of light). It creates fragments. This is due to of gravitational collapse of a star (Every star undergoes stellar evolution ~ collapse to non-hydrostatic equilibrium, and core collapse for dying stars)
>Aging massive star ceases to generate its energy from nuclear fusion (hydrogen fuel), it may undergo sudden gravitational collapse into a neutron star or black hole, releasing gravitational potential energy that heats and expels the star’s outer layers.
a. 1.44 solar masses (the Chandrasekhar limit) >white dwarfs
b. 2 to 3 solar masses (the Tolman-Oppenheimer-Volkoff limit)> quark star
c. Gravitational collapse will always occur on any star over 5 solar masses, inevitably producing a black hole
d. 5 Solar masses> Black Hole (Event Horizon> Time of no return)
2. Black Hole is composed of annihilation of dark and real matter. It has very Intense gravity that light also cannot escape, there is also "event horizon" that time cannot be back. Every annihilation of dark matter and real matter creates photon, the transmitter of light. Precedent of Pulsar are black holes.
>> Neutron star has dark matter and real matter inside. For every particle there is also have its antiparticle.
http://www.dtheatre.com/read.php?sid=4456
Dark Matter Trailer!
A trailer for a new film called Dark Matter has appeared online. According to it’s official synopsis, Dark Matter follows a Chinese science student in the United States in the early 1990s. Driven by ambition, yet unable to navigate academic politics, then, drama un-folds.
Duration : 0:2:5
What type of evidence is there for proving dark matter and dark energy exist and who was involved in creating the theory for dark matter and dark energy?
I asked questions relating to the big bang and dark matter and dark energy were referenced every so often, so, what are they? What impact do they have on the universe? Where are they located?
Copy of Question #7 asked again in a different category
"Dark Matter" is really a placeholder name for the stuff which we can barely detect by its gravity, but does not interact with matter in any other way.
It has been known for a while that there was quite a bit of mass in the universe that we couldn’t see. Literally it was ‘non luminous matter’. Its existence was inferred due to the observed rotation of galaxies. The material in galaxies rotated too fast, especially at the outer edge, for the luminous matter to be all that there was. For a long time it was assumed that the ‘missing matter’ was literally dust, debris, and burnt out stars. However, with the advent of space-based telescopes, we now know that there is simply not enough of that to account for the observations.
More recently we have been able to map the distribution of dark matter by looking at the distortion its mass causes in the background of distant galaxies. One famous example is the ‘bullet cluster’, which is actually two clusters of galaxies that are in the process of colliding. What was striking about this was that when the scientists mapped the gravitational lensing of the cluster, there were two ‘blobs’ of gravity extending beyond the colliding clusters. What has happened is that the normal (baryonic) matter in the clusters is colliding, heating up, forming stars, and generally getting hung up in a traffic jam of mass, but the ‘dark’ matter sailed on through and out the opposite sides of the collision. This was a startling confirmation of the exotic nature of dark matter, and that it wasn’t just inert matter, dust, debris, dead stars, etc.
Since then we’ve gotten a closer look at the galaxies, and it appears that every big galaxy is surrounded by a halo of dark matter.
So, we don’t know what it is, but we know it has mass (i.e., gravity). It doesn’t interact with normal matter, like gas or dust would. It bends light like matter does, so we can map its distribution by looking for gravitational lensing. In other words, its pretty weird stuff. I look forward to finding out more about it in the next few years.
Dark Energy is an even newer discovery than Dark Matter, and we know even less about it. This is the ‘energy’ or ‘force’ that is pushing out on the universe, and causing the expansion of the universe to accelerate.
Join UCSD Physicist Kim Griest as he takes you on an exploration of two of the major unsolved questions in the physical sciences: What might be the fate of the universe and what is the nature of the dark matter which ultimately decides this fate? Series: “UCSD Millennium Lectures” [2/2000] [Science] [Show ID: 4661]
Duration : 0:57:54
Is it significant that 73% of the matter in our universe is composed of dark energy? How does tie into string theory, and the idea of black holes, the big bang, and an inflationary universe? Does this dark matter exist in the extra dimensions predicted? Thanks.
These are opposite theories, The string theory says that the universe is held together by strings with infinite mass which are no thicker then a proton. the dark matter or anti matter theory claims that the universe is held down by the forces between dark matter and matter…