Stories tagged universe
Swedish cosmologist Max Tegmark thinks so.
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Is anybody out there?: If not, it'd be fine by me!
Courtesy NASA
Is there intelligent life elsewhere in the Universe? That’s a hot topic, both among astronomers and right here on Science Buzz. The argument goes like this:
• There are about 100 billion galaxies in the known Universe
• Each galaxy has about 100 billion stars.
• Even if only a small fraction of them have planets, that’s still an awful lot. Ya gotta figure at least some of them developed intelligent life.
And thus we go looking for signs of life in outer space: probes to Mars, searches for organic molecules, even scanning the skies for radio signals. So far… nothing.
Nick Bostrom is glad. This Oxford professor argues that finding life on other planets would be bad news for us here on Earth.
The way he sees it is this:
• The Universe is about 14.5 billion years old.
• Earth is about 4.5 billion years old.
• That’s plenty of time for intelligent life anywhere else in our galaxy, or even a nearby galaxy, to come pay a visit.
• They haven’t.
This convinces Bostrom that interstellar travel must be impossible – if it wasn’t, someone would have stopped in by now, if only to ask for directions.
What makes interstellar travel impossible? Bostrom and economist Robin Hanson theorize (or “theorise” – they are British, after all) the existence of one or more “Great Filters.” The evolution of life, from primordial ooze to galactic explorer, requires a vast number of steps, some so complicated as to be virtually impossible. Obviously, one of those steps has been preventing interstellar travel for the past 14.5 billion years, so it must be pretty good.
What does all this have to do with life here on Earth? Simply this: the identity of this filter, and whether it lies ahead of us or behind us, may very well determine the fate of all humanity.
If the filter lies behind us—especially if the filter lies wayyyy behind us—then we’re in good shape. We’ve passed the barrier that has stopped everybody else. But if the filter lies close to us—or, worse yet, ahead of us—then it spells big trouble. For example, perhaps the only way to travel the stars is to harness some great energy source: nuclear power, or perhaps something we haven’t discovered yet. And perhaps every civilization in the history of the Universe that discovered this power ended up blowing themselves up. It’s unlikely that we would be any different.
Bostrom’s conclusion is counter-intuitive but compelling. If, as we explore the Universe, we find life is rare, then that’s good news—Earth succeeded where every other planet failed. But if we find that life, especially complex, intelligent life, is common, then that doesn’t bode well at all. Whatever stopped those planets is likely going to stop us, too.
*(PS: The answer is, Tommy James and the Shondells, later covered by Tiffany -- both proof that intelligent life is exceedingly rare, even here on Earth.)
On March 19, there was a tremendous explosion in outer space. The massive gamma-ray burst was faintly visible to the naked eye, despite being 7.5 billion light years away. That’s half the distance across the Universe, and 1,000 times further than the previous record for most distant visible object. Gamma-ray bursts occur when giant stars run out of fuel and collapse, releasing huge amounts of energy.
Google Sky now works in a web browser (without a download). From within a web browser one can navigate the sky in a way similar to using Google Maps. Zoom or drag your way through a universe of stitched together images from telescopes and satellites. Try it out. It is lots of fun.
Artist rendition of newly formed planet orbiting its young star
Courtesy NASA/JPL-Caltech/R. Hurt (SSC)Astronomers in Germany have announced the discovery of a newborn planet in a distant solar system.
Johny Setiawan, of the Max Planck Institute for Astronomy in Heidelberg, discovered the extrasolar planet using the 2.2m Max-Planck-Gesellschaft telescope in Chile. He said it’s the first and so far earliest example of a planet observed during its formation process.
Planets are thought to form out of the disks of dust and gas swirling around newly created stars. The new planet, catalogued as TW Hydrae b, is situated in the constellation Hydrae some 180 light years from Earth, and is only about 8 or so million years old – a mere baby in terms of planetary formation. In fact, the star it circles isn’t much further along in its own development.
"This demonstrates that planets can form within 10 million years, before the disk has been dissipated by stellar winds and radiation," the researchers explained in a recent issue of the journal Nature.
The gaseous newborn’s mass is about 10 times that of Jupiter in our own solar system, and orbits at a distance of about 4 million miles, just inside the inner edge of its star’s disk of gas and dust.
"The discovery shows that what we always call as 'protoplanetary' disks are indeed protoplanetary; they form planets," Setiawan said. "There are many 'protoplanetary' disks detected around young stars, but no planets so far have been detected within such young systems."
MORE INFORMATION
BBC.com story
Story at SpaceRef.com
The Extrasolar Planets Encyclopaedia
Max Planck Institute for Astronomy
Astronomers in England have discovered 27 proto-galaxies -- lumps of gas and dust caught in the act of clumping together to form larger structures.
Every mad scientist movie of the 1950s featured, well, a mad scientist trying to destroy the world. Now it seems like normal, everyday scientists are on the verge of destroying the universe! Or so says a new theory by Lawrence Krauss of Case Western Reserve University in Cleveland, Ohio. He says that the Universe started out unstable, and has slowly been stabilizing as it matures. Unfortunately, scientists have rest the clock, pushing the Universe back to its unstable beginnings, simply by looking at it!
This has to do with a well-known but little-understood property of some sub-atomic particles. According to the Heisenberg Uncertainty Principle (I think), these particles will actually change their behavior when they are observed. By observing the Universe scientists have changed the Universe, in ways that Krauss fears may be a bit on the catastrophic side.
Other scientists express skepticism, and point to the fact that mankind has been observing the Universe for tens of thousands of years, and has been observing sub-atomic particles for decades, and the Universe has resolutely refused to explode. I, however, agree with Krauss – this is far too elegant a theory to permit mere facts to sway us too much.
A whole lotta nothing: Actual image of nothing. Photo courtesy Bryan Kennedy.This post is about nothing. A whole lot of nothing as a matter of fact. Or would it be better phrased: a fact of no matter? I’m not sure which is correct in this case.
Anyway, University of Minnesota astronomy professor Lawrence Rudnick and his research team has discovered an area in space – check that – a HUGE area in space where there seems to be a tremendous amount of nothing. Empty space. No stars, no planets, no dust, no dark matter, no Big Bang residual microwave energy, no nothing. I mean, yes nothing. And plenty of it.
"This is 1,000 times the volume of what we sort of expected to see in terms of a typical void," said Prof. Rudnick.
There’s evidently so much of it, in fact, that if you were able to travel at the speed of light (186,000 miles per second – or about 5.8 trillion miles per year) – it would take you about a billion years to cross it. Talk about a snooze-fest. I’d be completely bored to tears after the first two or three years.
But it seems appropriate that Rudnick be the one to discover this vast emptiness, since he seems to specialize in nothing.
He’s been teaching at the University of Minnesota since 1979, and has offered first year seminars in “Nothing”, bringing in experts to instruct his students on how “nothingness” is used or applied in various fields.
"It has a little bit of philosophy. I bring in people in different fields to talk about nothing in their fields. I've had artists come and talk about minimalist art, interior designers to talk about designing empty spaces,” Rudnick said. “I've had a blind person come and talk about seeing nothing and what does that mean."
Rudnick’s discovery came out of studying radio picture data of the universe taken from the National Radio Astronomy Observatory.
The area studied is located in the constellation Eridanus near the foot of Orion, and showed a distinct drop in temperature and lack of matter, up to 45% less matter.
Even though it’s really nothing, Rudnick remains modestly philosophical about it.
"It's not going to be tomorrow's pacemaker or anything like that," he said. "It is, however, part of the story of how we got here."
Rudnick’s research is scheduled to appear in an upcoming issue of Astrophysical Journal.
STORY LINKS
The Hubble Deep Field: The Most Important Image Ever Taken (Video). Worth watching.
Dark Matter revealed: Credit: NASA/SAO/CXC/M.Markevitch et al.
What the universe is made of
- 70% - dark energy
25% - dark matter
5% - ordinary matter
In a recent collision of galaxies known as the Bullet Cluster, scientists think they have proof of dark matter. In this cluster there are galaxies and intermixed gasses. When there was a collision, the gasses slowed more than the galaxies. Measurements showed that large amounts of mass that that should have fallen behind with the gasses continued ahead with the galaxies.
"This provides the first direct proof that dark matter must exist and that it must make up the majority of the matter in the Universe." said study leader Doug Clowe, from the University of Arizona.
Proof of the invisible
Observations of our universe have not "fit" into our theories about how the universe should behave. To solve this dilemma, scientists "invented" what they call dark matter and dark energy. Dark matter refers to matter that does not emit or reflect enough electromagnetic radiation (light) to be detected directly, but whose presence may be inferred from its gravitational effects on visible matter. An example is when light from a known star is bent too much as it goes near a galaxy. The explanation is that the galaxy must have some invisible (dark) matter. Several other observable phenomena support that galaxies, clusters of galaxies, and the universe as a whole contain far more matter than is directly observable, indicating that the remainder is dark.
Alternative explanations
A second explanation is that gravity does not behave the same way in galaxy clusters light years in size as it does on Earth.
A proposed alternative to physical dark matter particles has been to suppose that the observed inconsistencies are due to an incomplete understanding of gravitation. To explain the observations, the gravitational force has to become stronger than the Newtonian approximation at great distances or in weak fields.
Source: NASA press release
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