COSMOLOGY

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  • #38955
    SadGeezerSadGeezer
    Keymaster

    I’m starting a cosmology thread since there’s so much new information coming out, and well, I’m interested in it. 😀

    From today’s NY Times (front page yet!)

    For Astronomers, Big Bang Confirmation

    By DENNIS OVERBYE
    The most detailed and precise map yet produced of the universe just after its birth confirms the Big Bang theory in triumphant detail and opens new chapters in the early history of the cosmos, astronomers said yesterday.
    It reveals the emergence of the first stars in the cosmos, only 200 million years after the Big Bang, some half a billion years earlier than theorists had thought, and gives a first tantalizing hint at the physics of the “dynamite” behind the Big Bang.

    Astronomers said the map results lent impressive support to the strange picture that has emerged recently: the universe is expanding at an ever-faster rate, pushed apart by a mysterious “dark energy.”
    By comparing their data with other astronomical observations, the astronomers have also made far more precise calculations of the basic parameters that characterize the universe, including its age, geometry, composition and weight.

    In a nutshell, the universe is 13.7 billion years old, plus or minus one percent; a recent previous estimate had a margin of error three times as much. By weight it is 4 percent atoms, 23 percent dark matter – presumably undiscovered elementary particles left over from the Big Bang – and 73 percent dark energy. And it is geometrically “flat,” meaning that parallel lines will not meet over cosmic scales.
    The result, the astronomers said, is a seamless and consistent history of the universe, from its first few seconds, when it was a sizzling soup of particles and energy, to the modern day and a sky beribboned with chains of pearly galaxies inhabited by at least one race of puzzled and ambitious bipeds.

    The map, compiled by a satellite called the Wilkinson Microwave Anisotropy Probe, shows the slight temperature variations in a haze of radio microwaves believed to be the remains of the fires of the Big Bang. Cosmologists said the map would serve as the basis for studying the universe for the rest of the decade…

    …The task now…is to understand those motley elements, the dark stuff that apparently makes up 96 percent of everything, and what happened in the Big Bang that gave birth to it all.

    Cosmologists do not know what dark energy is. One leading candidate is a repulsive force called the cosmological constant, which Einstein created as a fudge factor to keep the universe from collapsing in his equations, and later disavowed. But some theories of modern physics postulate mysterious force fields called quintessence as the dark energy. While the new analysis has not solved the problem, Dr. Spergel said its data seemed to favor Einstein’s fudge factor.

    There’s a lot more interesting stuff, here’s the link to the article:
    http://www.nytimes.com/2003/02/12/science/12COSM.html

    And here’s a link to the graphics at the WMAP site:
    http://map.gsfc.nasa.gov/.

    I love the terminology that these scientists use: dark energy, dark matter, quintessence….pure poetry :mrgreen: How frustrating that we’re still so earthbound!

    elmey

    (I’m not sure why this post ended up being so wide–have no clue what to do about it, sorry!)

    #64975
    Anonymous
    Guest

    I saw short report on BBC News 24 which was so diabolically bloody stupid it almost made me change channel. The BBC have begun to dumb down their news reporting lately – so much so, that by the time the report had finished I didn’t even know what the hell it was about.

    Your post has helped clarify things a lot! Thanks elmey.

    #68243
    Anonymous
    Guest

    More new cosmology stuff. This is really cool:

    Sept. 10, 2003, 2:02PM
    A song no human ear can hear
    Sound from Perseus cluster is 57 octaves below middle C
    Associated Press
    WASHINGTON — The voice of a black hole is a deep, deep bass, 57 octaves below middle C and far beyond the hearing range of humans. The Chandra X-ray Observatory has picked up sound waves for the first time from a cluster of galaxies 250 million light years away.

    Astronomers at the Institute of Astronomy in Cambridge, England, discovered the sound waves while analyzing the Chandra images of the Perseus cluster, an immense grouping of galaxies held in formation by the powerful tug of a supermassive black hole.

    …the sound produced by the black hole is a B flat, the same pitch as a key near middle C on the piano. But the song of the Perseus Black Hole is 57 octaves below that middle C. This is a tone frequency more than a million, billion times deeper than the limits of the human ear…

    But the voice of the black hole could never be heard by the human ear because there are 10 million years between each of the sound waves, “clearly not within human experience,” said Fabian…

    “We’ve known that a black hole can give off energy as light and heat and now we are seeing a third way — sound.”

    Didn’t Pythagoras postulate that all celestial bodies emit their own individual tone? Who knew! 😉

    Here’s the official press release on the subject:

    Chandra hears a Black Hole[/url]

    Check out the black hole animation on the page while you’re at it.

    elmey

    #68983
    lizard
    Participant

    Everybody who gets the chance should check out Brian Greene’s NOVA (on pbs in the us) series about string theory, called the Elegant Universe. His book is very nice.

    http://www.pbs.org/wgbh/nova/elegant/

    This series started with a nice historical introduction to modern physics and makes use of computer animation to get the ideas across. (The presentation is almost completely free of mathematics– a good or bad thing depending on your tastes.)

    I really enjoyed the discussion of quantum mechanics. (Space at the quantum level is depicted as a crazy bumpy place with wild music) The pictures showing the difference between Newton’s concept of gravity and Einstien’s were the best I have ever seen.

    There are also interviews with some physicists like S. Weinberg who are very interesting to listen to.

    Everyone interested in writing scifi should tune in– because in string theory there are plenty of extra dimensions and possible multiverses to play in.

    #72316
    Anonymous
    Guest

    OK, more space sounds: crank up your speakers and play this:

    The Big Bang

    Cool eh? It’s the sound of the first million years after the big bang, compressed to 5 seconds (1 second per 200,000 years)

    Or more exactly, it’s an acoustic analysis of the tiny fluctuations in the cosmic microwave background — which we’ve been able to date back as far as just 400,000 years after the Big Bang.

    Dr. Mark Whittle (U of Virginia) was in charge of this project and for those of you who haven’t clicked the link yet, he describes the sound like this:

    “…a descending scream, building into a deep rasping roar, and ending in a deafening hiss. As if this were not impressive enough, the entire acoustic show is itself the prelude to a wonderful transformation: the highest pitch sounds ultimately spawn the first generation of stars, while the deep bass notes slowly dissolve to become the tapestry of galaxies which now fills all of space. The birth of the Universe, it turns out, had its own primal scream.”

    Makes you want to listen now, yes? The complete page with various analyses of the sound and more is here:

    Dr. Whittle’s Audio Page

    and from there you can also click to his homepage which has more extensive descriptions of what’s going on when you listen to the sounds–read the Press Release if this interests you, it’s a very clear explanation. If I can understand it, anyone can…..:wink:

    And I know you were going to ask how we can hear sounds in the vacuum of space. According to Doc Whittle:

    “Space wasn’t so empty when the Universe was young. Remember,
    the Universe is expanding so it was smaller in the past, and all the
    matter we now see in stars and galaxies was spread out uniformly to
    make a hot thin gas, a kind of cosmic “atmosphere”. It is within this
    atmosphere that sound waves could form, grow and move.”

    Also interesting: the actual sound is 50 octaves below the lowest octave on a piano (they’ve shifted it up to make the audio). But the volume is in human range for the first million years–after 400,000 years it’s still at 110 decibels.

    It’s really an amazing 5 seconds of audio when you realize what it represents. I found the original article in the Times a few weeks ago and got to the Doctor’s site from there.

    elmey

    #72389
    Anonymous
    Guest

    cool stuff, elmey!! 😀 it;s reading stories like this that makes me all the more determined to see through my studies. even though the workload is turning me into a wreck! i’ve always been fascinated by the space sciences and the more i reaad, the more i want to be up there with all the people finding out all this stuff.
    keep the articles coming!! 😀

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