Brian Greene: Back to blow your mind.
Having explained string theory to the masses in his bestseller The Elegant Universe and untangled the fabric of the cosmos in The Fabric of the Cosmos, the superstar physicist returns this month with The Hidden Reality, an ode to multiverse theory.
By now, the 11-dimension string theory models of his earlier books … are looking downright commonsensical. “The Hidden Reality” moves on to increasingly speculative and exotic discussions of a bubble multiverse (“Think of the universe as a gigantic block of Swiss cheese. …”) a holographic one, a brane-world scenario (courtesy of string theory), computer-driven simulations, questions of how probability relates to infinity, and the Many Worlds view of quantum mechanics. “A frequent criticism of the Many Worlds approach is that it’s just too baroque to be true,” Mr. Greene writes. [The New York Times]
Multiverse theory—the idea that our universe and its Big Bang were just one of many—is a favorite theme of science fiction (and “Family Guy”), as it allows us to have parallel selves in parallel universes. Greene explains the real science behind the idea with one of his litany of analogies: a simple deck of cards.
If you shuffle the deck infinitely many times, the card orderings must necessarily repeat. Similarly, in an infinite expanse of space, particle arrangements must repeat too—there just aren’t enough different particle configurations to go around. And if the particles in a given region of space the size of ours are arranged identically to how they are arranged here, then reality in that region will be identical to reality here. Except that maybe we’d be seeing the Jets and the Bears in the Super Bowl. [Wall Street Journal]
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Its’ time for another mind-blowing, record-breaking discovery by the Hubble Space Telescope. This time, it’s creeping closer than ever toward the beginning of the universe.
From Phil Plait:
Astronomers have just announced they have discovered what may be the most distant galaxy ever seen, smashing the previous record holder. This galaxy is at a mind-crushing distance of 13.2 billion light years from Earth, making it not just the most distant galaxy but also the most distant extant object ever detected!
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Named UDFj-39546284, the galaxy is seen as it was just 480 million years after the Universe itself formed! The previous record holder — which was announced just last October — was 13.1 billion light years away. This new galaxy beats that by 120 million light years, a substantial amount. Mind you, these galaxies formed not long after the Big Bang, which happened 13.73 billion years ago. We think the very first galaxies started forming 200 – 300 million years after the Bang; if that’s correct then we won’t see any galaxies more than about 13.5 billion light years away. Going from 13.1 to 13.2 billion light years represents a big jump closer to that ultimate limit!
For plenty more about this, check out the rest of Phil’s post at Bad Astronomy.
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Image: NASA, ESA
More than a trillion pixels from a million-plus images, combined to create the most detailed map of the universe ever created—one that would require a wall of a half-million HDTVs to properly appreciate. Not bad for something that looks a little like tan carpeting.
What you’re seeing is about one-third of the sky, imaged by the Sloan Digital Sky Survey, which has been assembling images from Apache Point Observatory in New Mexico for more than a dozen years to image the cosmos in unprecedented detail.
It replaces an image that is now over half a century old, created on photographic plates by the Palomar Sky Survey in the 1950s but still used by astronomers today. It contains 10 times as many objects – such as galaxies, stars and nebulae – as the Palomar survey and scientists hope it will be used for decades to come by astronomers hunting for everything from dark matter to planets orbiting other stars. [The Guardian]
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A study by Yale astronomer Pieter van Dokkum just took the estimated number of stars in the universe—100,000,000,000,000,000,000,000, or 100 sextillion—and tripled it. And you thought nothing good ever happens on Wednesdays.
Van Dokkum’s study in the journal Nature focuses on red dwarfs, a class of small, cool stars. They’re so small and cool, in fact, that up to now astronomers haven’t been able to spot them in galaxies outside our own. That’s a serious holdup when you’re trying to account for all the stars there are.
As a consequence, when estimating how much of a galaxy’s mass stars account for – important to understanding a galaxy’s life history – astronomers basically had to assume that the relative abundance of red-dwarf stars found in the Milky Way held true throughout the universe for every galaxy type and at every epoch of the universe’s evolution, Dr. van Dokkum says. “We always knew that was sort of a stretch, but it was the only thing we had. Until you see evidence to the contrary you kind of go with that assumption,” he says. [Christian Science Monitor]
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The Big Bang was not the beginning, Roger Penrose believes.
The eminent Oxford physicist has long advocated the wild idea of “conformal cyclic cosmology,” a cyclical universe without beginning or end in which the Big Bang 13.75 billion years ago was simply one of many. This month, Penrose pushed his idea further: His team says it has detected a pattern in the cosmic microwave background—radiation left over from just after the Big Bang—that represents the echo of events that occurred before the Big Bang itself.
Penrose examined the data from the Wilkinson Microwave Anisotropy Probe (WMAP), the mission that just completed nine years of surveying the cosmic microwave background across the sky. His study points to concentric circular patterns in the WMAP data where he says he found something surprising:
The circular features are regions where tiny temperature variations in the otherwise uniform microwave background are smaller than average. Those features, Penrose said, cannot be explained by the highly successful inflation theory, which posits that the infant cosmos underwent an enormous growth spurt, ballooning from something on the scale of an atom to the size of a grapefruit during the universe’s first tiny fraction of a second. Inflation would either erase such patterns or could not easily generate them. [Science News]
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Its multicolored ovals have become some of the most distinguishable pictures in science. Its estimate of the age of the universe is the most accurate ever produced. Its science team ought to win the Nobel Prize for Physics, Nobel predictors at Thomson Reuters say. But now, after nine years in space, the accomplished Wilkinson Microwave Anisotropy Probe (WMAP) is headed for its retirement home.
The spinning WMAP satellite scanned the sky to measure tiny variations in the temperature of the cosmic microwave background radiation 380,000 years after the Big Bang. Scientists consider the CMB the first light from the young universe after matter and light could exist independently as the universe cooled. Only sensitive microwave space telescopes can detect the temperature fluctuations, which amount to just a millionth of a degree against an average backdrop of less than -450 degrees Fahrenheit. [Spaceflight Now]
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In a bizarre finding that has disrupted the current understanding of the universe, astronomers have detected evidence of a massive gravitational force beyond the horizon of the observable universe. What’s being called a dark flow appears to be pulling vast clusters of galaxies toward a 20-degree-wide patch of sky between the constellations of Centaurus and Vela. “It does fly in the face of everything we know,” said astronomer Dale Kocevski…. “I’m sure it’s going to be controversial” [Discovery News].
When scientists talk about the observable universe, they don’t just mean as far out as the eye, or even the most powerful telescope, can see. In fact there’s a fundamental limit to how much of the universe we could ever observe, no matter how advanced our visual instruments. The universe is thought to have formed about 13.7 billion years ago. So even if light started travelling toward us immediately after the Big Bang, the farthest it could ever get is 13.7 billion light-years in distance. There may be parts of the universe that are farther away (we can’t know how big the whole universe is), but we can’t see farther than light could travel over the entire age of the universe [SPACE.com].
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