The sheer size of the universe.
AdamSummerfield 23 Oct 2006
I am often in awe while thinking upon one of my favourite topics. Especially when looking upon pictures that Hubble has taken, like the Ultra Deep Field.
How do you guys feel about the size fo the universe? Even if we take just our Galaxy and look at the size of it, 100 Billion stars, it is believed that 0.6% of those stars have Jupiter-sized planets orbiting them. So this must mean that a small percentage (but still resulting in many) of stars must have liquid-water-bearing planets orbiting them.
The figures of this are so large, that it must be true, that somewhere in this galaxy, there is an alien race carving messages on cave walls, and another race building artificial planets and advancing its technology beyond our wildest dreams.
Then perhaps, turn your minds gaze to intergalactic space - if you dare -, here you can see the huge inimaginable distance between galaxies, and how far into the distance the galaxies stretch. Out here, there must be countless planets, countless alien races.
Its a wonderful chance we have been given. The ability to ponder these things with our advanced minds (when comparing to other animals on our planet).
Please share your thoughts.
bgwowk 23 Oct 2006
There is suggestive evidence that the probability of simple life arising spontaneously (or perhaps getting seeded from space) is high. Specifically, microbe fossils have been found on earth from practically the time the surface was cool enough to support them. It may be that the rate-limiting step in the development of intelligent life is the jump from simple to complex life. This is supported by the observation that complex life arose late and suddenly in the earth's history. For billions of years there was nothing here but bacteria. Perhaps much of the universe is like that.
I assume you are aware of the Fermi paradox, which speaks strongly against the existence of other intelligent tool-makers in the visible universe. Anywhere intelligent life arises, it will likely explode outward at near the speed of light for basic evolutionary reasons. We don't see any evidence that this has occurred yet, so *we* may be the seed that spreads life and intelligence through the universe (Dyson's "Greening of the Galaxy").
Edited by bgwowk, 23 October 2006 - 10:37 PM.
AdamSummerfield 24 Oct 2006
I am/was aware that the chance of intelligent life existing in the galaxy was all probability - all numbers, but no assurance that it was true.
But I maintain the very strong belief that there is other intelligent life in our galaxy, let alone the universe.
And also, I have not heard of the Fermi paradox. I have always relied on my own philosophy when it comes to galactic span, intelligent life, and world building/predicting.
RighteousReason 24 Oct 2006
Ok you need to connect those two. Your beliefs should reflect the probability. In this case, the means of calculating this probability are ... rather difficult and inaccurate.I am/was aware that the chance of intelligent life existing in the galaxy was all probability - all numbers, but no assurance that it was true.
But I maintain the very strong belief that there is other intelligent life in our galaxy, let alone the universe.
I say damn the estimations- let's go look for ourselves!
Of course, this Universe is so unimaginably huge, it would be quite necessary to ensure we can stay alive through the billions of years of our travels.
bgwowk 24 Oct 2006
AdamSummerfield 24 Oct 2006
amar 24 Oct 2006
Lazarus Long 24 Oct 2006
(Amar)
The big bang theory might be true of our galaxy (maybe the cosmic condom broke) but I doubt that it's true of the entire universe.
The Big Bang far exceeds our galaxy and its impact is upon all the literally billions of galaxies we now observe or suspect are out there.
We are seeing back in time to almost the beginning through telescopes due to the distances involved. In fact I read an article about a week or so ago that claims we are actually able observe real time conditions all the way to a few hundred million years and maybe less after the moment on the Big Bang.
Perhaps this is what you are referring to Amar in an essay right out of today's paper.
Knowing the Universe in Detail (Except for That Pesky 96 Percent of It)
By DENNIS OVERBYE
Published: October 24, 2006
Hardly anyone remembers now, but 1991 was a bad year for the Big Bang.
Astronomers were having more and more difficulty reconciling their models of the explosion that gave birth and impetus to the expanding cosmos with the structure of the modern universe, in particular the discovery of strings of clusters and so-called superclusters of galaxies going hundreds of millions of light-years across the sky.
There was a rash of articles in prestigious journals like Science and even this newspaper saying that major elements of the model, or even the Big Bang itself, might have to be junked. “Big Bang Blown to Bits,” read one headline I remember.
I took all this rather personally because the publication of my first book, which was about cosmology, coincided with the appearance of these headlines. The cosmic jig was up, and I wasn’t getting invited onto any talk shows.
But in April 1992, George Smoot from the University of California, Berkeley, announced that the NASA satellite Cosmic Background Explorer, or Cobe, had detected faint irregularities in a bath of microwaves that pervade space.
The microwaves are presumed to be cooling radiation from the original fireball, and the splotches were the right size to one day grow into giant clusters of galaxies.
“If you are religious, it is like looking at God,” Dr. Smoot said.
This month Dr. Smoot and John Mather, of the Goddard Space Flight Center, the head Cobe scientist, were awarded the Nobel Prize in Physics. There was much talk that Cobe had marked a turning point, the beginning of a “golden age,” in which cosmology went from a collection of vague ideas to a precision science.
Indeed, subsequent observations have parsed the meaning of those lumps, allowing cosmologists to converge on a remarkably detailed picture of the universe. The Big Bang, they now say, happened 13.7 billion years ago, plus or minus 150,000 years. That is a far cry from the days when some astronomers were ready to go to the mat over whether it was 10 billion or 20 billion years ago and when others shrugged and said a factor of two was pretty good in cosmology.
Moreover, they now say, ordinary atomic matter of the kind that makes up you, me and the stars is 4 percent of the cosmos; dark matter that floats as gravitational glue between the stars and galaxies is 20 percent; and dark energy, which is apparently accelerating the cosmic expansion, pushing the galaxies faster and faster apart, is 76 percent, plus or minus 2 percent.
You might wonder just exactly what kind of triumph “precision cosmology” represents when 96 percent of the universe is unknown dark stuff. Stars and people we know about. But the best guess for dark matter is that it is some kind of subatomic particle that will be discovered someday.
Dark energy was a complete surprise. How often do you toss a handful of gravel into the air and the rocks speed up as they leave your hand and disappear into the sky? The leading contender for an explanation is a fudge factor representing the repulsive force of empty space that Einstein danced in and out of his equations 75 or so years ago. But no one really knows.
Apparently we now know enough to say that the universe is precisely “preposterous,” in the words of Sean Carroll, a physicist and blogger at the California Institute of Technology. Michael Turner, a cosmologist at the University of Chicago, likes to say, “We know much, but we understand little.”
Critics of the Big Bang mutter darkly that all these mysterious elements in the equation are reminiscent of the epicycles, circles upon circles added to the orbits of the planets back in the Middle Ages to maintain the appearance that they were circling the Earth. Sometimes I wonder if the astrophysicists have been too glib for their own good. By adding dark energy and dark matter on top of black holes, they have overextended the “dark” brand just when we need a fresh dose of wonder.
But I didn’t buy the death of the Big Bang 15 years ago, and I don’t buy the criticism now. Particle physicists had already predicted the existence of extra “dark” particles before cosmologists put them to work. And antigravity, the dark energy, in precisely the amount discovered by two rival teams of astronomers in 1998, turned out to be the ingredient that made the Big Bang models finally work. Nobody had a chance to jiggle the numbers.
Sometimes the game comes to you. It was by following the light that cosmologists were led into the dark.
Still, the universe can always use a new Copernicus or Einstein. Thanks to the Cobe scientists and their successors, these are boom times for the Big Bang. After all, 96 percent of the universe is still waiting to be found.
Now I will look for that article on the age. I think I read it in Live Science
Lazarus Long 24 Oct 2006
Universe not Pill-Shaped, it is open : Dr. Raj Baldev
MIL, Oct 12, 2006. Henry Groover
California, October 12, 2006 - Scientists announced that instead of the widely held theory that the universe is spherical, recent data reveals that the universe might be stretched in a shape like a pill. But Dr. Raj Baldev, Cosmo Theorist from India, does not agree with this finding. He said that the space is eternal, having no shape or flat shape; hence no question of Pill shaped Universe arises.
Scientists in Italy based their study on data gathered by the Wilkinson Microwave Anisotropy Probe (WMAP), a NASA satellite designed to measure the temperature of residual heat from the Big Bang. They said the ellipsoid form of the universe could be caused by a magnetic field pervading the cosmos and stretching the fabric of space and time.
It is claimed that data from the NASA probe helped nail down very important details about the universe.
These details include the age of the universe since the Big Bang occurred, (13.7 billion years old), the time when the first atoms formed (380,000 years after the Big Bang) and showed that the universe is made of five percent ordinary matter, 25 percent dark matter and 70 percent dark energy.
WMAP found that the first stars emerged about 400 million years after the Big Bang, a period previously estimated to be 200 million years. (exzcerpt)
Lazarus Long 24 Oct 2006
2 win Nobel for picture of backfire from Big Bang
Discovery gave physicists a detailed look at our past and future--how the universe began
By Ronald Kotulak
Tribune science reporter
Published October 4, 2006
Two physicists who obtained a satellite picture of the infant universe a mere 389,000 years after its explosive birth 13 billion years ago--a feat most scientists thought would never be achieved--have been awarded the 2006 Nobel Prize in physics.
Many consider their accomplishment the most important development in the field of cosmology, cementing the Big Bang theory as the best explanation for how the universe began, showing how stars and galaxies formed and providing scientists with a marvelous time machine for exploring the past and future of the cosmos.
For their measurement of cosmic background radiation--the afterglow of the Big Bang--John Mather of NASA's Goddard Space Flight Center in Maryland and George Smoot of the University of California at Berkeley will share the $1.37 million prize at a ceremony Dec. 10 in Stockholm, Nobel officials announced Tuesday.
"The discovery literally opened the gate to the golden age of cosmology that we're in," said Michael Turner of the University of Chicago. "It's a fantastic discovery that's enabling us to learn about the universe, how old it is, its shape and its composition."
The measurements of the microwave radiation were taken by the COBE satellite, or Cosmic Background Explorer, which began returning spectacular results within hours after it was launched into Earth orbit in 1989. The information transformed cosmology from an art into a precise science, according to physicists.
(excerpt)
amar 24 Oct 2006
Lazarus Long 24 Oct 2006
That's right we are looking directly at the primordial universe when it was a little over a quarter of a million years old because of how long it has taken the light of those events to reach us.
bgwowk 24 Oct 2006
The earliest light we can see is 13.7 billion years old. As Laz said, that was 380,000 years after the Big Bang, when the universe first became transparent. That "light" is the 3K cosmic microwave background radiation. When we look at the cosmic microwave background, we are looking directly at the plasma fire ball that gave birth to the universe. Seeing back any earlier than 380,000 years is impossible because plasma is opaque.
This universe is bounded in time and space, at least on one end. There are however a possibly infinite number of other universes in the so-called "multiverse," but that is another subject.
JonesGuy 25 Oct 2006
What I like about the vastness of space is the sheer opportunity of wealth. Right now, we scramble for a few hectares of one planet. If we learn to harvest space, there are billions of stars available for each person. We only suffer poverty because of poor resource utilization!
AdamSummerfield 28 Oct 2006
I think overall, can we agree that the chances of life in our universe; albeit in our galaxy are extremely high?
DukeNukem 29 Oct 2006
This is probably true. The universe cannot exceed the influence of gravity (which propagates at the speed of light). During the inflationary period the universe (and gravity's reach) increased at the apparent speed of a millions of times faster than light, but that inflation lasted a fraction of a second, and from that point on it is the reach and speed of gravity that likely defines the universe's size. Infinities likely do not exist in nature.The universe is not infinite since the speed of inflation was not infinite
amar 29 Oct 2006
caston 29 Oct 2006
Edited by caston, 29 October 2006 - 12:00 PM.
halcyondays 31 Oct 2006
This is probably true. The universe cannot exceed the influence of gravity (which propagates at the speed of light). During the inflationary period the universe (and gravity's reach) increased at the apparent speed of a millions of times faster than light, but that inflation lasted a fraction of a second, and from that point on it is the reach and speed of gravity that likely defines the universe's size. Infinities likely do not exist in nature.
How can we know how fast the universe itself is expanding? We can't see out that far, since it is expanding faster than the speed of light (Otherwise we should be able to see the edge of the Universe). I don't think we can honestly say how Large or fast the Universe is, or what is beyond that. Is the edge of the universe an actual wall, or is it a shockwave? Who really knows. Maybe in 100 billion years we will have the technology to discover these things...
Edited by halcyondays, 31 October 2006 - 02:19 AM.
JonesGuy 31 Oct 2006
Lazarus Long 31 Oct 2006
(halcyondays)
Is the edge of the universe an actual wall, or is it a shockwave? Who really knows. Maybe in 100 billion years we will have the technology to discover these things...
Calling it a shockwave would be more appropriate than calling it a wall and yes we can *see it*, you don't have to wait 100 billion years the tech exists today and is getting refined very fast.
QJones is correct, we are measuring the acceleration of that shockwave of heat that is the residual effect of the Big Bang and is called *background radiation* as it accelerates away from us in all directions. We can literally see all the way to that receding wall of background radiation and measure its velocity by a variety of methods the most common being the Doppler Effect .
Is there anything on the other side of it?
That is the big question. The basic argument of modern physics is that nothing exists on the other side of it. By nothing I do not mean vacuum, I mean NOTHING, no space/time. What we are seeing is the actual inflation of this universe (our space/time reality) and that is why many consider our universe finite.
What is discussed in terms of the immediate post moments of the Big Bang is that the universe inflated at a velocity well in excess of the speed of light and then slowed down to below that speed. Once it slowed down, the energy and gravity from all objects in the universe began to propagate and interact.
The prevalent theory is that the farthest we can observe translates into the age of the universe as calculated with respect to the speed of the light traveling to us, as that is how long it has taken the light to cross the extent of the inflation (this is simplified with respect to the modifying factors that are calculated into the figure).
Cosmic microwave background radiation (Wiki)
The Cosmic Background Radiation
Hot Big Bang model
Tests of the Big Bang: The CMB
Lazarus Long 31 Oct 2006
So you add that figure to the time it took the *light* (in the form of microwaves on the EM spectrum) of the cosmic background radiation to reach us and you have the age of the universe , at roughly 13.7 billion years.
amar 31 Oct 2006
Lazarus Long 31 Oct 2006
However you could be correct and the infinite universe theory still has adherents that try to rationally explain contradictory data but the data we currently have does not support that model unless the model is redefined in terms that it has not yet found either mathematically or empirically.
I posted the dual bang hypothesis above BTW.
amar 31 Oct 2006
Edited by amar, 31 October 2006 - 06:21 PM.
halcyondays 31 Oct 2006
Seems like there are more questions than answers when you really get into it.
DukeNukem 01 Nov 2006
If we can never exceed light speed we will never be able to try to see for ourselves the so-called universe's edge. But, the fact is, we might be right on that edge and not know it. People assume we're at the center and we need to go 14 billion light years in one direction to reach the edge. Wrong. There may be no edge in the way people think of boundaries. The universe might be like a Mobius Strip that turns in on itself due to gravity/dark matter/dark energy and other forces.
The bottom-line is that too much is still unknown to really give anything close to a definitive answer, but most likely nothing will ever penetrate the edge because we will never find an edge to penetrate -- it doesn't really exit.
Infernity 01 Nov 2006
-Infernity
Lazarus Long 01 Nov 2006
There is nothing on the *otherside* of the leading edge because all that exists is on this side of the *inflation* that is still accelerating. Also what we are looking at is the *trailing edge* from heat that is only 380,000 years after the Big Bang. It is more a wake than the actual *edge* but the physics of what defines the *edge* is still not clearly defined and that is one point on which I think we all agree.
http://www.nature.co...ature02139.html
http://www.nature.co...ature04805.html
The Big Bang violates GRT because the initial inflation exceeded light speed and the subsequent slow down is well below C to allow for the fact that it is accelerating toward C. The other side of this continued *inflation* is not defined by GRT and definitely requires a new order of physics to do so. Gravity also doesn't exist there as we define and understand gravity.
Maybe Hawking radiation exists but that is the same stuff that defies gravity in a Black Hole theoretically. Calculating the velocity of inflation has to do with Hubble's Constant and the red shift.
http://www.nature.co...s/323132a0.html
http://www.nature.co...ature02139.html
http://www.nature.co...ature03282.html
http://www.jhu.edu/n...jun06/shaw.html
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Astronomer Is Co-Winner of Million-Dollar Shaw Prize
Johns Hopkins University astrophysicist Adam Riess and two colleagues today were awarded this year's $1 million Shaw Prize in astronomy for their discovery that an unexplained, mysterious "dark energy" is driving an ever-faster expansion of the universe.
Adam Riess
Co-winners of the 2006 prize with Riess are Saul Perlmutter of the Lawrence Berkeley Laboratory of the University of California, Berkeley, and Brian Schmidt of the Mount Stromlo Observatory of the Australian National University in Canberra.
Riess and Schmidt were leaders of one team that pursued highly difficult and challenging measurements that led to the dark energy discovery in 1998. Perlmutter was the leader of a competing team.
***
"We set out to measure the expansion rate of the universe in the past and compare it to the expansion rate of the present universe, using exploding stars called supernovae," Riess said. They expected to find that gravity — the force by which everything in the universe tugs at everything else and tends to attract it all together — had slowed the rate of expansion over time.
"So it was startling to find that the expansion rate was speeding up," Riess said.
That, he said, sent astronomers back to an idea developed but eventually discarded by Albert Einstein as "my biggest blunder." That idea, Riess said, implied that there might be a sort of "anti-gravity" — that "the vacuum of space had energy in it and that energy could act repulsively and accelerate the expansion of the universe."