Tag Archives | Universe

Large Asteroid 2005 YU55 to Pass Earth — Closer Than Moon

Asteroid 2005 YU55Edward Lovett and Ned Potter Report on ABC News:

We have a visitor — a large asteroid called 2005 YU55 that is expected to come within approximately 201,700 miles of Earth on Tuesday, according to NASA. That’s slightly less than the distance from Earth to the moon.

Asteroids often pass this close, but most are tiny. Countless thousands of pieces come plunging into the atmosphere, but they burn up without doing any harm. If they’re as large as grains of sand, we may, if we’re lucky, see them in the night sky as shooting stars.

But 2005 YU55 is at least 1,300 feet wide — larger than an aircraft carrier, according to radar measurements. The last time an asteroid this big passed by was in 1976, and the next one scientists know of won’t be until 2028, NASA says. (There have been some rude surprises in between, but not involving anything remotely as large.)
Don Yeomans, manager of NASA’s Near-Earth Object Program Office at Jet Propulsion Laboratory, in Pasadena, Calif., said this fly-by is an opportunity to learn more about c-type — that is, carbon-based — asteroids, to find “clues as to what it was like when our solar system was forming.”

More: ABC News

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The Largest Galaxy Clusters in the Universe Hint That Something is Behaving Strangely

Galaxy Cluster LCDCS-0829Via the Daily Galaxy:

The large-scale structure of the Universe appears to be dominated by vast “hyperclusters” of galaxies, according to the new the Sloan Digital Sky Survey, compiled with a telescope at Apache Point, New Mexico. The survey plots the 2D positions of galaxies across a quarter of the sky. The science team has concluded that it could mean that gravity or dark energy — or something completely unknown — is behaving very strangely.

We know that the universe was smooth just after its birth. Measurements of the cosmic microwave background radiation (CMB), the light emitted 370,000 light years after the big bang, reveal only very slight variations in density from place to place. Gravity then took hold and amplified these variations into today’s galaxies and galaxy clusters, which in turn are arranged into big strings and knots called superclusters, with relatively empty voids in between.

On even larger scales, though, cosmological models say that the expansion of the universe should trump the clumping effect of gravity.

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Microbes Found Preadapted for Life in Space

Space MicrobesVia the Daily Galaxy (some have been unable to get this link, here is the cached version):

Microbes born on Earth are already pre-adapted for journeying through space, living in space, and not just surviving but flourishing in radioactive environments where they are continually exposed to radiation by ions similar to what might be encountered in a nebular cloud.

In 1958, physicists discovered clouds of bacteria, ranging from two million bacteria per cm3 and over 1 billion per quart, thriving in pools of radioactive waste directly exposed to ionizing radiation and radiation levels millions of times greater than could have ever before been experienced on this plane.

The world’s first artificial nuclear reactor was not even built until 1942. Prior to the 1945, poisonous pools of radioactive waste did not even exist on Earth. And yet, over a dozen different species of microbe have inherited the genes which enable them to survive conditions which for the previous 4.5 billion years could have only been experienced in space.

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Time Reversal: A Simple Particle Could Reveal New Physics

Time ReversalShelley Littin writes in Space Daily:
A simple atomic nucleus could reveal properties associated with the mysterious phenomenon known as time reversal and lead to an explanation for one of the greatest mysteries of physics: the imbalance of matter and antimatter in the universe. The physics world was rocked recently by the news that a class of subatomic particles known as neutrinos may have broken the speed of light. Adding to the rash of new ideas, University of Arizona theoretical physicist Bira van Kolck recently proposed that experiments with another small particle called a deuteron could lead to an explanation for one of the most daunting puzzles physicists face: the imbalance of matter and antimatter in the universe. A deuteron is a simple atomic nucleus, or the core of an atom. Its simplicity makes it one of the best objects for experiments in nuclear physics ...
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How The Universe (Something) Appeared From Nothing (Video)

Granted this video is a promo for the New Scientist's recent issue on "existence", it's pretty interesting, if you are OK with incomplete answers. (Figuring out how the universe got so large is still a serious head-scratcher.) My takeaway after watching this, is if "something" is not really that different from "nothing" (according to our human perception) then, well, there is still much to ponder ...
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‘Multiverse’ Theory Suggested By Microwave Background

Bubbles_3D“It would be a pretty amazing thing to show that we have actually made physical contact in another universe. It’s a long shot, but it would by very profound for physics” (Prof. Efstathiou). Via BBC:

The idea that other universes – as well as our own – lie within “bubbles” of space and time has received a boost.

Studies of the low-temperature glow left from the Big Bang suggest that several of these “bubble universes” may have left marks on our own.

This “multiverse” idea is popular in modern physics, but experimental tests have been hard to come by.

The preliminary work, to be published in Physical Review D, will be firmed up using data from the Planck telescope.

For now, the team has worked with seven years’ worth of data from the Wilkinson Microwave Anisotropy Probe, which measures in minute detail the cosmic microwave background (CMB) – the faint glow left from our Universe’s formation.

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Black Hole Hosts Universe’s Most Massive Water Cloud

Photo: NASA

Photo: NASA

A giant quasar billions of light-years away is surrounded by water vapor that could fill Earth’s oceans over 140 trillion times. Via National Geographic:

In a galaxy 12 billion light-years away resides the most distant and most massive cloud of water yet seen in the universe, astronomers say.

Weighing in at 40 billion times the mass of Earth, the giant cloud of mist swaddles a type of actively feeding supermassive black hole known as a quasar.

Among the brightest and most energetic objects in the universe, quasars are black holes at the centers of galaxies that are gravitationally consuming surrounding disks of material while burping back out powerful energy jets.

“As this disk of material is consumed by the central black hole, it releases energy in the form of x-ray and infrared radiation, which in turn can heat the surrounding material, resulting in the observed water vapor,” said study co-author Eric Murphy, an astronomer with the Carnegie Observatories in Pasadena, California.

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Planet Earth Has A Stalker

Earth StalkerMichael Reilly reports in the New Scientist:

An asteroid 300 metres in diameter is stalking the Earth. Hiding in the pre-dawn twilight, it has marched in lockstep with our planet for years, all but invisible to our telescopes.

The rock is Earth’s first confirmed Trojan, which can orbit the sun in either of two gravitational wells along the same orbital path as our planet. From the sun’s point of view, these wells lie 60 degrees ahead of and behind the Earth, at Lagrange points where gravitational forces between the sun and the Earth balance out.

Trojans are common — Jupiter alone boasts about 5000, and Neptune and Mars each have their own smaller collections. But finding Earth’s has proven difficult, because the Lagrange points lie towards the sun in the sky. Astronomers must look for the objects just before the sun rises or after it sets, and until now the glare of this sunlight has obscured the feeble light reflected from any rocks that might be hiding there.

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