From Scientific American: Within Any Possible Universe, No Intellect Can Ever Know It All
David Wolpert, a computer scientist at NASA, proves that as part of the universe, we can never understand and learn every single thing about it.
Showing posts with label cosmology. Show all posts
Showing posts with label cosmology. Show all posts
Friday, February 20, 2009
old gas learning new tricks
From New Scientist: 'Primordial' gas ring gives birth to baby galaxies
The Leo ring is "a giant stream of hydrogen and helium gas" around two "older" galaxies about 35 million light years away. Discovered in the early '80s, the ring is thought to have formed early in the history of the universe. Recently, though, clumps of young stars have been found in the ring. These "infant dwarf galaxies" are considered very unique because they formed without the assistance of dark matter, which is strange because it's theorized that dark matter is the seed of galaxies, pulling regular matter in, and also because other dwarf galaxies have been observed to contain up to 10,000 times as much dark matter as regular matter. Scientists are planning to measure the metallicity of the cloud to see if it really is as old as they think it is.
The Leo ring is "a giant stream of hydrogen and helium gas" around two "older" galaxies about 35 million light years away. Discovered in the early '80s, the ring is thought to have formed early in the history of the universe. Recently, though, clumps of young stars have been found in the ring. These "infant dwarf galaxies" are considered very unique because they formed without the assistance of dark matter, which is strange because it's theorized that dark matter is the seed of galaxies, pulling regular matter in, and also because other dwarf galaxies have been observed to contain up to 10,000 times as much dark matter as regular matter. Scientists are planning to measure the metallicity of the cloud to see if it really is as old as they think it is.
the barns of the earth
From New Scientist: Do gravity holes harbour planetary assassins?
Ignore the title of this article; it relates to a silly extra article. The bulk of this is about Lagrangian points, which are places in space where the gravitational field of the Earth (or any planet) cancels out the gravity of the Sun. These areas actually have zero gravity, as opposed to the microgravity we usually see. A pair of probes called STEREO that launched in 2006 to observe the sun will also be used to observe L4 and L5, the two most stable of Earth's Lagrangian points.
The author also discusses Lagrangian point in regards to the most popular theory of the Moon's origin. If a Mar-sized object collided with the Earth in the distant past to form the Moon, where did that object come from? Perhaps L4 or L5, where the object would have been able to grow to that size and then be nudged out of orbit by the gravity of another body in the solar system, like Venus.
Ignore the title of this article; it relates to a silly extra article. The bulk of this is about Lagrangian points, which are places in space where the gravitational field of the Earth (or any planet) cancels out the gravity of the Sun. These areas actually have zero gravity, as opposed to the microgravity we usually see. A pair of probes called STEREO that launched in 2006 to observe the sun will also be used to observe L4 and L5, the two most stable of Earth's Lagrangian points.
The author also discusses Lagrangian point in regards to the most popular theory of the Moon's origin. If a Mar-sized object collided with the Earth in the distant past to form the Moon, where did that object come from? Perhaps L4 or L5, where the object would have been able to grow to that size and then be nudged out of orbit by the gravity of another body in the solar system, like Venus.
tell me a story about quantum theory
From Scientific American: Was Einstein Wrong?: A Quantum Threat to Special Relativity
I've heard how there is something about quantum theory that violates Einstein's theory of relativity, but I didn't know that at least part of that is non-locality. I should have, considering my fascination with quantum entanglement. Anyway, this article details the history of the contradictions between these two theories. Being very lay-person and also very ill, it took me a long time to read it, but it's definitely very interesting.
I've heard how there is something about quantum theory that violates Einstein's theory of relativity, but I didn't know that at least part of that is non-locality. I should have, considering my fascination with quantum entanglement. Anyway, this article details the history of the contradictions between these two theories. Being very lay-person and also very ill, it took me a long time to read it, but it's definitely very interesting.
Saturday, February 14, 2009
old-timey stars super friendly
From ScienceDaily: Ultra-Compact Dwarf Galaxies: Stars Packed Together In Early Universe A Million Times More Closely
ScienceDaily always has very literal titles, doesn't it? Kind of ruins the little bit of surprise for my post. Perhaps they should use more metaphors and figurative, oblique language. Or perhaps I should just stop quoting the titles beforehand.
Anyway! Ultra-compact dwarf galaxies! Sweet! These were very early galaxies, and very small and dense: mostly around 60 light years across, but a million times more crowded than what we're used to, so there was around a million stars in a cubic light year instead of just one.
ScienceDaily always has very literal titles, doesn't it? Kind of ruins the little bit of surprise for my post. Perhaps they should use more metaphors and figurative, oblique language. Or perhaps I should just stop quoting the titles beforehand.
Anyway! Ultra-compact dwarf galaxies! Sweet! These were very early galaxies, and very small and dense: mostly around 60 light years across, but a million times more crowded than what we're used to, so there was around a million stars in a cubic light year instead of just one.
black holes in possible action
From io9: What Would a Black Hole Really Look Like?
io9 is a fun science fiction blog that's especially awesome because it also talks about science and how reality and fiction collide. In this post, Annalee talks about science art and illustration of black holes. There are a couple really sweet videos. Can't go wrong with the collision of two black holes!
io9 is a fun science fiction blog that's especially awesome because it also talks about science and how reality and fiction collide. In this post, Annalee talks about science art and illustration of black holes. There are a couple really sweet videos. Can't go wrong with the collision of two black holes!
Friday, February 13, 2009
all waves, all the time
From ScienceDaily: NASA's SkyView Delivers The Multiwavelength Cosmos
This article talks about SkyView, a nifty little tool from NASA that shows pictures of space, from many sources, at many wavelengths. Pretty and fun!
This article talks about SkyView, a nifty little tool from NASA that shows pictures of space, from many sources, at many wavelengths. Pretty and fun!
Friday, February 6, 2009
jellyfish galaxy
From ScienceDaily: Exceptionally Deep View Of Strange Galaxy
Really pretty pictures of an uncommon type of spiral galaxy in the Coma Cluster, which is about 321 million light years away and contains mostly elliptical galaxies. Around and even through it, "thousands of much more remote galaxies of all shapes, sizes and colours are visible. Many have the spotty and ragged appearance of galaxies at a time before the familiar division into spirals and ellipticals had become established."
Really pretty pictures of an uncommon type of spiral galaxy in the Coma Cluster, which is about 321 million light years away and contains mostly elliptical galaxies. Around and even through it, "thousands of much more remote galaxies of all shapes, sizes and colours are visible. Many have the spotty and ragged appearance of galaxies at a time before the familiar division into spirals and ellipticals had become established."
Saturday, January 24, 2009
origins of the dark flow
From New Scientist: Dark flow: Proof of another universe?
First off: did you know 45 billion light years is the furthest we can observe from Earth? I did not, and I don't quite understand how considering the universe is only supposed to be a little less than 14 billion years old. (I've heard of inflation and all that, but I'm still boggled.)
Anyway, this is a pretty interesting article about something called dark flow. Apparently, a team from NASA led by Dr. Sasha Kashlinsky noticed that there are a lot of galaxy clusters (they were studying almost 800) "racing at up to 1000 kilometres per second" "toward a small patch of sky between the constellations of Centaurus and Vela." (They're southern constellations; take a look at this map around -40˚.) This is strange because galaxies and galaxies clusters should be moving along with the expansion of space. Kashlinsky thinks something on the "cosmic horizon" is causing this, where conditions could be totally different from what they are in the observable universe, where matter and energy are fairly evenly distributed.
Other theories: "the dark flow is caused by other universes exerting a gravitational pull on galaxy clusters in our universe[;]" "dark flow could be a sign that our bubble universe crashed into another bubble just after the big bang[;]" or that the current cosmological model is wrong, matter is not evenly distributed, and "that at large scales matter is like a fractal."
It makes me a little sad that we might never know.
First off: did you know 45 billion light years is the furthest we can observe from Earth? I did not, and I don't quite understand how considering the universe is only supposed to be a little less than 14 billion years old. (I've heard of inflation and all that, but I'm still boggled.)
Anyway, this is a pretty interesting article about something called dark flow. Apparently, a team from NASA led by Dr. Sasha Kashlinsky noticed that there are a lot of galaxy clusters (they were studying almost 800) "racing at up to 1000 kilometres per second" "toward a small patch of sky between the constellations of Centaurus and Vela." (They're southern constellations; take a look at this map around -40˚.) This is strange because galaxies and galaxies clusters should be moving along with the expansion of space. Kashlinsky thinks something on the "cosmic horizon" is causing this, where conditions could be totally different from what they are in the observable universe, where matter and energy are fairly evenly distributed.
Other theories: "the dark flow is caused by other universes exerting a gravitational pull on galaxy clusters in our universe[;]" "dark flow could be a sign that our bubble universe crashed into another bubble just after the big bang[;]" or that the current cosmological model is wrong, matter is not evenly distributed, and "that at large scales matter is like a fractal."
It makes me a little sad that we might never know.
Wednesday, January 21, 2009
indecent singularities
From Scientific American: Do Naked Singularities Break the Rules of Physics?
In this article, Dr. Pankaj Joshi at the Tata Institute of Fundamental Research in Mumbai discusses the possibility of naked singularities. (I know that sounds a little naughty, but bear with me, because it actually is thrilling in its own way.) Naked singularities are basically black holes, without an event horizon. So, there would be a point of infinity density without the same effect on gravity; there would not be the same "point of no return" as there is with black holes. In addition, if naked singularities do exist, it would be possible for them to be observed directly. Theoretical models seem to show that with a certain inhomogeneity of density in a star, this type of singularity could be formed.
In this article, Dr. Pankaj Joshi at the Tata Institute of Fundamental Research in Mumbai discusses the possibility of naked singularities. (I know that sounds a little naughty, but bear with me, because it actually is thrilling in its own way.) Naked singularities are basically black holes, without an event horizon. So, there would be a point of infinity density without the same effect on gravity; there would not be the same "point of no return" as there is with black holes. In addition, if naked singularities do exist, it would be possible for them to be observed directly. Theoretical models seem to show that with a certain inhomogeneity of density in a star, this type of singularity could be formed.
the womb of the big bang
From Scientific American: The First Stars in the Universe
And now back to your regularly scheduled science.
I've been reading a lot of these "story of a theory" type articles a lot in the past few days. I like them because they're easier to understand as a layperson, which I guess makes sense because they're actually stories that are coming from mainstream science magazines.
Anyway, this article is, just as it says, about the first stars in the universe. How they formed, how long ago, how massive they were. Answers: possibly small variations in density, between 100 and 250 million years after the Big Bang, and between 300 and 1000 solar masses.
And now back to your regularly scheduled science.
I've been reading a lot of these "story of a theory" type articles a lot in the past few days. I like them because they're easier to understand as a layperson, which I guess makes sense because they're actually stories that are coming from mainstream science magazines.
Anyway, this article is, just as it says, about the first stars in the universe. How they formed, how long ago, how massive they were. Answers: possibly small variations in density, between 100 and 250 million years after the Big Bang, and between 300 and 1000 solar masses.
Monday, January 19, 2009
m theory, dark matter, and a phoenix universe
From New Scientist: Did dark energy give us our cosmos?
This theory puts together a couple of my favorite ideas. First, in M theory, our universe is just a part of a larger structure. The article talks about it "exists on a 3D region called a 'brane' separated from similar branes by a fourth spatial dimension." Sometimes, these branes collide, causing something like the big bang. Next, the universe is in a never-ending cycle of bang, expansion, and then contraction. (I like this because not only does it answer the question of what came before the big bang, but it also eliminates eternal expansion and eternal death of heat, light, etc., which scares me in a way it shouldn't considering I won't live that long.)
The problem with this idea is that all the different parts of the extended 'verse would have to move to fit expanding and contracting branes, so "large areas of the brane become warped, so that most of it ends up as black holes and only a tiny proportion as ordinary, habitable space." But! Add the element of dominant, pervasive dark matter, and the theory starts to come together. Sweet.
This theory puts together a couple of my favorite ideas. First, in M theory, our universe is just a part of a larger structure. The article talks about it "exists on a 3D region called a 'brane' separated from similar branes by a fourth spatial dimension." Sometimes, these branes collide, causing something like the big bang. Next, the universe is in a never-ending cycle of bang, expansion, and then contraction. (I like this because not only does it answer the question of what came before the big bang, but it also eliminates eternal expansion and eternal death of heat, light, etc., which scares me in a way it shouldn't considering I won't live that long.)
The problem with this idea is that all the different parts of the extended 'verse would have to move to fit expanding and contracting branes, so "large areas of the brane become warped, so that most of it ends up as black holes and only a tiny proportion as ordinary, habitable space." But! Add the element of dominant, pervasive dark matter, and the theory starts to come together. Sweet.
blowing my mind
From New Scientist: Our world may be a giant hologram
I can't even begin to talk about this crazy, amazing research. So I'll just quote from the article.
I can't even begin to talk about this crazy, amazing research. So I'll just quote from the article.
For the past seven years, this German set-up has been looking for gravitational waves - ripples in space-time thrown off by super-dense astronomical objects such as neutron stars and black holes. GEO600 has not detected any gravitational waves so far, but it might inadvertently have made the most important discovery in physics for half a century.I can't decide if I'm freaked out, or amazed, or both.
For many months, the GEO600 team-members had been scratching their heads over inexplicable noise that is plaguing their giant detector. Then, out of the blue, a researcher approached them with an explanation. In fact, he had even predicted the noise before he knew they were detecting it. According to Craig Hogan, a physicist at the Fermilab particle physics lab in Batavia, Illinois, GEO600 has stumbled upon the fundamental limit of space-time - the point where space-time stops behaving like the smooth continuum Einstein described and instead dissolves into "grains", just as a newspaper photograph dissolves into dots as you zoom in. "It looks like GEO600 is being buffeted by the microscopic quantum convulsions of space-time," says Hogan.
If this doesn't blow your socks off, then Hogan, who has just been appointed director of Fermilab's Center for Particle Astrophysics, has an even bigger shock in store: "If the GEO600 result is what I suspect it is, then we are all living in a giant cosmic hologram."
Friday, January 16, 2009
dark matter close to home?
From Scientific American: Does Dark Matter Encircle Earth?
Just like scientists, I think dark matter is awesome, both because it is incredibly mysterious and because it apparently goes through normal matter. And its mysteriousness is apparently only equal to our inability to find any of it.
However, Stephen Adler, a theoretical physicist at the Institute for Advanced Studies, has said there should be study of the Earth and Moon to see if any dark matter is present close by. "If the mass of Earth and the moon when measured together seems greater than their masses separately, the difference could be attributed to a halo of dark matter in between." He says that the presence of dark matter in the solar system could also solve the unexplained on other planets, like how the interiors of the outer gas giants are hotter than we think they should be.
Annika Peter, an astrophysicist at CIT, counters, saying that the latter idea would require "a seriously unrealistic amount of dark matter," and that there probably isn't any dark matter in the solar system itself. But perhaps a little outside it?
Just like scientists, I think dark matter is awesome, both because it is incredibly mysterious and because it apparently goes through normal matter. And its mysteriousness is apparently only equal to our inability to find any of it.
However, Stephen Adler, a theoretical physicist at the Institute for Advanced Studies, has said there should be study of the Earth and Moon to see if any dark matter is present close by. "If the mass of Earth and the moon when measured together seems greater than their masses separately, the difference could be attributed to a halo of dark matter in between." He says that the presence of dark matter in the solar system could also solve the unexplained on other planets, like how the interiors of the outer gas giants are hotter than we think they should be.
Annika Peter, an astrophysicist at CIT, counters, saying that the latter idea would require "a seriously unrealistic amount of dark matter," and that there probably isn't any dark matter in the solar system itself. But perhaps a little outside it?
Wednesday, January 7, 2009
all grown up and making carbon monoxide
From Scientific American: Did the universe mature at an early age?
More discoveries about the early universe, this time about two billion years after the Big Bang, or whatever beginning it was, which is about 11.5 billion years ago.
I guess maybe a lack of galactic collisions. A little peace and quiet.
More discoveries about the early universe, this time about two billion years after the Big Bang, or whatever beginning it was, which is about 11.5 billion years ago.
[A]stronomers announced that cosmic gas in that period, seen when backlit by a gamma-ray burst (a gigantic stellar explosion), contained molecular hydrogen and carbon monoxide—the first time astronomers have discovered molecules, as opposed to isolated atoms or ions, in the light of a gamma-ray burst. The molecules’ presence indicates that the galaxy where the burst occurred was nearly as chemically developed as the present-day Milky Way.I'm curious now... theoretically, there was very, very little metal in the beginning of the universe, and so the earliest stars should have no metal (called Population III or metal-free stars, you can read about this at the Metallicity article are Wikipedia). Wikipedia says (I know Wikipedia can be a little dicey, but for basics like this I think it's ok) that "theory is divided on whether the first stars were very massive or not," but considering everything was just masses of light gases expanding, I think they must have been massive, and thus had very quick life cycles and pumped out a lot of new elements. And since this new evidence is showing that chemically, the universe is pretty similar 11.5 billion years ago as it is now, does that mean that there is the slim possibility that life could have formed anytime since then? I mean, life on Earth needed, what? Earth itself. So iron, nickel, other metals, and other heavier elements. Hydrogen and carbon monoxide means our basic organic building blocks were there - carbon and water. What else does life need?
I guess maybe a lack of galactic collisions. A little peace and quiet.
what came first?
From BBC News: Black holes 'preceded galaxies'
It was unclear whether black holes came first, helping create galaxies by pulling matter towards them, or whether they arose in already formed galaxies.This is pretty interesting. The infancy of the universe is a mysterious time. I guess this makes sense, though. The universe was much smaller at around 1 billion years old. Maybe those metal-poor stars back then were the same way today's metal-rich stars are: lots of different sizes and masses, and some of them had to become black holes and then pull matter and stars to themselves as the universe expanded.
"It looks like the black holes came first," said Dr Chris Carilli, from the US National Radio Astronomy Observatory in Socorro, New Mexico, who took part in the study. "The evidence is piling up."
Saturday, December 13, 2008
dark matter egg hunt
From ScienceDaily: New Detector Will Aid Dark Matter Search
Can I just say that dark matter is kind of awesome?
Dr. Jocelyn Monroe, the scientist working on the project, said that there'll probably be the discovery of a dark-matter particle sometime in the next five years. I can't wait. The universe will never be boring.
Can I just say that dark matter is kind of awesome?
Dr. Jocelyn Monroe, the scientist working on the project, said that there'll probably be the discovery of a dark-matter particle sometime in the next five years. I can't wait. The universe will never be boring.
Tuesday, December 9, 2008
milky way super cute black hole
From BBC News: Black hole found in Milky Way
Kickass! They found our black hole. Apparently it's 4 million times heavier than the Sun and 27,000 light years away. I wanted to calculate the mass, but the mass of the sun has thirty zeros and I can't deal with that. Instead, I'll compare it to the mass of the Sun as compared to the mass of the Earth. The Sun has the mass of 332,946 Earths, so our black hole is... 1,331,784,000,000 Earths. I think that's right.
What should we call it? Milky Way Black Hole is pretty long. I was thinking "the Milky Hole," but I realized that just sounded really dirty.
Kickass! They found our black hole. Apparently it's 4 million times heavier than the Sun and 27,000 light years away. I wanted to calculate the mass, but the mass of the sun has thirty zeros and I can't deal with that. Instead, I'll compare it to the mass of the Sun as compared to the mass of the Earth. The Sun has the mass of 332,946 Earths, so our black hole is... 1,331,784,000,000 Earths. I think that's right.
What should we call it? Milky Way Black Hole is pretty long. I was thinking "the Milky Hole," but I realized that just sounded really dirty.
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