Near-Earth asteroid 2005 YU55 will pass within 0.85 lunar distances from the Earth on November 8, 2011.

The upcoming close approach by this relatively large 400 meter-sized, C-type asteroid presents an excellent opportunity for synergistic ground-based observations including optical, near infrared and radar data.

The attached animated illustration shows the Earth and moon flyby geometry for November 8th and 9th when the object will reach a visual brightness of 11th magnitude and should be easily visible to observers in the northern and southern hemispheres. (…)

Although classified as a potentially hazardous object, 2005 YU55 poses no threat of an Earth collision over at least the next 100 years.

However, this will be the closest approach to date by an object this large that we know about in advance and an event of this type will not happen again until 2028 when asteroid (153814) 2001 WN5 will pass to within 0.6 lunar distances.

{ NASA | Continue reading }

photo { Alex Prager }

One the big questions that trouble cosmologists and particle physicists is the distribution of matter and antimatter in the Universe. It certainly looks as if matter dominates the cosmos but looks can be deceiving. We may just live in a corner of the universe that happens to be dominated by matter.

Today, we find there’s a little extra antimatter in our corner thanks to the work of the STAR collaboration at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory in the US.

These guys banged together 10^9 gold nuclei at energies of 200 GeV and spotted 18 antinuclei of helium-4 in the ensuing wreckage. That’s an impressive achievement by an standards–at the very least we now know antihelium-4 can exist.

{ The Physics arXiv Blog | Continue reading }

photo { Edward Weston }

When we hear the word “universe,” we think that means everything: every star, every galaxy, everything that exists. But in physics, we’ve come upon the possibility that what we’ve long thought to be everything may actually only be a small part of something that is much, much bigger. The word “multiverse” refers to that bigger expanse, the new totality of reality, and our universe would be just a piece of that larger whole.

Scientists have many proposals. In some, the other universes have the same laws of physics and the same particles making up matter. So except perhaps for some environmental differences, pretty much what we see here is what happens there. In some multiverse proposals, the other universes could be radically different from what we know, the particles could be different, the laws of physics could appear different. And in others—ones that frankly don’t compel me—even the kinds of mathematics that govern the physics in those realms might be different from the math that we are familiar with.

{ Research/Columbia University | Continue reading }

image { Mars and Beyond, Disney, 1957 }

Even if there was a highly advanced and intelligent alien species out there and it was starved of resources after tens of millions of years of existence in one form or another, we wouldn’t be a likely destination for invasion. We’d probably be too far away and too expensive to attack for a pretty minor payoff.

Everything aliens could find on our planet could be found in greater abundance and higher densities in asteroid belts and comet-rich clouds left over from solar system formation.

{ Weird things | Continue reading }

In 1978, the NASA scientist Donald Kessler predicted that a collision between two pieces of space junk could trigger a cascade of further impacts, creating dangerously large amounts of debris.

Kessler pointed out that when the rate at which debris forms is faster than the rate at which it de-orbits, then the Earth would become surrounded by permanent belts of junk, a scenario now known as the Kessler syndrome.

By some estimates, the Kessler syndrome has already become a reality. In January 2009, a collision between the Iridium 33 and Cosmos 2251 satellites created just this kind of cascade. Two years earlier, the Chinese military tested an anti-satellite weapon by destroying one of its own satellites called Fengyun 1C. Both incidents took place at altitudes of about 800 km. (…)

Various ideas have been floated for removing space junk, most of them hugely expensive.

Today, James Mason at NASA Ames Research Center near Palo Alto and a few buddies describe a much cheaper option. Their idea is to zap individual pieces of junk with a ground-based laser, thereby slowing them down so that they eventually de-orbit.

{ The Physics arXiv Blog | Continue reading }

The Kepler observatory was launched into orbit in early 2009. Its mission: to search for planets in solar systems other than our own. Their recent results point to a staggering number of planets that share the galaxy with us, many of which orbit their sun in a habitable temperature zone: between 0 and 100 °C. This means that water-based life such as ourselves would neither freeze nor boil away, assuming that the planet has atmospheric pressure similar to Earth. (…)

Based on the approximate value of 100 billion stars in our galaxy, scientists with Kepler estimate at least 50 billion planets (one out of every two stars is expected to have a planet). And 500 million or so of those planets are in the habitable temperature zone.

{ Berkeley Science Review | Continue reading }

A giant net several kilometres in size has been built as part of a collaboration between Japan’s space agency and a 100-year-old fishing net company to collect debris from space.

Last year, a US report concluded that space was so littered with debris that a collision between satellites could set off an “uncontrolled chain reaction” capable of destroying the communications network on Earth. It is estimated there are 370,000 pieces of space junk.

The Japanese plan will see a satellite attached to a thin metal net spanning several kilometres launched into space. The net is then detached, and begins to orbit earth, sweeping up space waste in its path.

During its rubbish collecting journey, the net will become charged with electricity and eventually be drawn back towards earth by magnetic fields – before both the net and its contents burn upon entering the atmosphere.

{ Telegraph | Continue reading }

Nasa has 18 facilities across the US, from Maryland to California, and its major contractors, companies such as Boeing and Lockheed Martin, have dozens more. But no place has assumed the identity of the country’s space programme quite like Brevard County. A mosquito-bitten slip of coast, 20 miles wide and 70 miles long, it was somewhere people used to drive through on their way to Palm Beach, until the US army decided to start testing its missiles there in October 1946.

And then, quite suddenly, it was colonised. The arrival of Wernher von Braun, designer of the V2 rocket, and the other founding fathers of the US space programme, made Brevard the fastest-growing county in America. Nasa, founded in 1958, built bridges and water systems, and when the space race reached its exorbitant heights in the mid-1960s, Brevard was the edge of the world. Astronauts raced their cars on the beach, newsmen camped out on their lawns and the county was given the dialling code 3-2-1 after the launch sequence. In 1973, Brevard put the Moon landing on its county seal.

The Apollo boom was followed by bust: 10,000 people lost their jobs when the programme was cancelled in 1972. But since then, Brevard has rebuilt itself around the space shuttle, Nasa’s longest-serving spacecraft and one of the most recognisable vehicles ever to fly. The parts may be manufactured elsewhere and its missions managed from Houston, but for the past three decades Brevard County and KSC have been, in Nasa-speak, where the rubber hits the road. The tourist-friendly launches and everlasting work of 132 missions have made the shuttle the central activity of America’s Space Coast—the stuff of daily life and conversation. (…)

Brevard hasn’t escaped the property crash. Property values in Brevard County have fallen by 45 per cent since 2007 and are still falling—more than 10 per cent last year. (…) Yet it is nothing compared to what is to come, because the rockets and the recession are about to collide. There will be at least two or maybe three missions this year: Discovery, planned for February; the official final flight, Endeavour, scheduled for 1st April; and possibly a “final final” mission if Atlantis gets the go-ahead, most likely in June. But at some point in 2011, the space shuttle will fly for the last time.

{ Prospect | Continue reading }

photo { Brian Ulrich }

Defining a galaxy sounds so simple. We all know what a galaxy is, right? Well, not really. Surprisingly, there is no universally agreed upon definition and the ones generally bandied around leave a great deal of wriggle room.

All this has been thrown into stark relief in recent years by the discovery of a growing number of small, faint, galaxy-like objects that were entirely unknown until now. These have been given various names such as ultra compact dwarfs, ultra-faint dwarf spheroidal galaxies and dwarf elliptical galaxies.

But it isn’t entirely clear whether they have more in common with galaxies like our own or globular clusters, which astronomers generally do not think of as galaxies.

That makes the problem of defining a galaxy a growing concern.

{ The Physics arXiv Blog | Continue reading }

photo { Wallpiercing LED lighting system, designed by Ron Gilad for Flos }

A good reason not to try sex in space. Yet.

One of the dominant ideas for getting to another solar system within the next few centuries involves the generation ship, vast spacecraft designed to function as their own, self-contained colonies and housing thousands of humans for very long stretches of time, ideally with all the comforts of home. And one of those comforts better be gravity because it turns out that if humans were to start reproducing without that familiar acceleration of 9.8 m/s/s or pretty close to it, their children are likely to be born with cranial defects, collapsed jaws, and buckled spines, among some of the other pleasantries of embryos’ inability to cope with a lack of gravity during the development process.

{ Weird Things | Continue reading }

photo { James O’Mahoney}

{ DailyMail }

{ Scientific American | full story }

related { Astronomers Find First Evidence Of Other Universes }

The universe seems vast, distant, and unknowable. It is, for example, unimaginably large and old: The number of stars in our galaxy alone exceeds 100 billion, and the Earth is 4.5 billion years old. In the eyes of the universe, we’re nothing. (…)

Clearly, our brains are not built to handle numbers on this astronomical scale. While we are certainly a part of the cosmos, we are unable to grasp its physical truths. (…) However, there actually are properties of the cosmos that can be expressed at the scale of the everyday. (…)

It turns out that there is one supernova, a cataclysmic explosion of a star that marks the end of its life, about every 50 years in the Milky Way. The frequency of these stellar explosions fully fits within the life span of a single person, and not even a particularly long-lived one. So throughout human history, each person has likely been around for one or two of these bursts that can briefly burn brighter than an entire galaxy.

On the other hand, while new stars are formed in our galaxy at a faster rate, it is still nice and manageable, with about seven new stars in the Milky Way each year. So, over the course of an average American lifetime, each of us will have gone about our business while nearly 550 new stars were born.

{ Boston Globe | Continue reading }

photo { 美撒guo }

Circular patterns within the cosmic microwave background suggest that space and time did not come into being at the Big Bang but that our universe in fact continually cycles through a series of “aeons.” That is the sensational claim being made by University of Oxford theoretical physicist Roger Penrose, who says that data collected by NASA’s WMAP satellite support his idea of “conformal cyclic cosmology”. This claim is bound to prove controversial, however, because it opposes the widely accepted inflationary model of cosmology.

According to inflationary theory, the universe started from a point of infinite density known as the Big Bang about 13.7 billion years ago, expanded extremely rapidly for a fraction of a second and has continued to expand much more slowly ever since, during which time stars, planets and ultimately humans have emerged. That expansion is now believed to be accelerating and is expected to result in a cold, uniform, featureless universe.

Penrose, however, takes issue with the inflationary picture and in particular believes it cannot account for the very low entropy state in which the universe was believed to have been born – an extremely high degree of order that made complex matter possible. He does not believe that space and time came into existence at the moment of the Big Bang but that the Big Bang was in fact just one in a series of many, with each big bang marking the start of a new “aeon” in the history of the universe.

{ PhysicsWorld | Continue reading }

related { In an experiment to collide lead nuclei together at CERN’s Large Hadron Collider physicists discovered that the very early Universe was not only very hot and dense but behaved like a hot liquid. }

photo { Young Kyu Yoo }

related:

{ The Scale of the Universe }

At about 3am on 8 October last year, an asteroid the size of a small house smashed into the Earth’s atmosphere over an isolated part of Indonesia. The asteroid disintegrated in the atmosphere causing a 50 kiloton explosion, about four times the size of the atomic bomb used to destroy Hiroshima. The blast was picked up by several infrasound stations used by the Comprehensive Nuclear-Test-Ban Treaty Organization to monitor nuclear tests.

No one was injured in the blast but the incident highlights the threat that planet faces from near Earth asteroids. Astronomers expect a strike like this once every 2-12 years. And the US congress has given NASA the task of sweeping the skies to identify anything heading our way. So far NASA has looked for objects of a kilometre or more in size and determined that none of these is on track to hit Earth in the foreseeable future.

But what of smaller objects? Various estimates show that an impact with an asteroid just 50 metres across would cause some 30,000 deaths (compared with 50 million deaths from an impact with a 1 kilometre-sized object).

This raises two important questions. The first is how best can astronomers monitor the skies for these smaller objects. The second is what to do should we find something heading our way.

{ The Physics arXiv Blog | Continue reading }

{ Scientists discovered two bubbles of energy erupting from the center of the Milky Way galaxy | NY Times | full story }

Some astronauts report losing their fingernails on spacewalks because of bulky gloves that cut off circulation and chafe against their hands. To avoid this inconvenience, a couple astronauts have taken to ripping off their own fingernails before reaching orbit.

{ PopSci | Continue reading }

Of the nearly 500 planets known beyond our solar system, nearly all appear to be gas-shrouded giants like Jupiter or Neptune, and most are either too hot or too cold to harbor life-giving liquid water. In contrast, with only three to four times the mass of Earth, Gliese 581g is probably mostly made of rock, and is at the proper distance from its star to have lakes, seas, even oceans of water upon its surface. If confirmed by follow-up observations, Gliese 581g will be the most promising potentially habitable planet discovered so far.

{ Seed | Continue reading }

photo { Li Wei }

{ It might be a place that only a lichen or pond scum could love, but astronomers said Wednesday that they had found a very distant planet capable of harboring water on its surface, thus potentially making it a home for plant or animal life. Nobody from Earth will be visiting anytime soon: The planet, which goes by the bumpy name of Gliese 581g, is orbiting a star about 20 light-years away in the constellation Libra. | NY Times | full story }

I’m sure most of you have heard of the twin paradox “in which a twin makes a journey into space in a high-speed rocket and returns home to find he has aged less than his identical twin who stayed on Earth.” This paradox has been worked out for special relativity in Minkowski spacetime. Recently, Boblest et al. worked out the details using general relativity for an expanding universe. (…)

The twins in the paper have names: Eric and Tina. Eric stays on Earth while Tina accelerates away from Earth with constant acceleration α = 9.8 m/s² until her clock shows 5 years have past. Then she decelerates by the same magnitude coming to a complete stop after ten years then begins her journey back to earth accelerating then decelerating in the same 5 year intervals. Finally, after 20 years has transpired on her clock she has returned to earth being now 20 years old. (…) Eric is nearly 350 years old when Tina returns.

{ The Eternal Universe | Continue reading }

About 13.7 billion years ago, the big bang created a big mess of matter that eventually gave rise to life, the universe, and everything. Now a new material may help scientists understand why.

The material was designed to detect a theorized but unproven property of electrons, subatomic particles with a negative charge that orbit the centers of atoms.

If this “new” property of electrons exists, scientists say, it would help explain the current imbalance between matter and antimatter in the universe. (…)

The sheer fact that we’re here must mean that matter behaves slightly different than antimatter, so that over time the universe has accumulated more ordinary matter than antimatter.

{ National Geographic | Continue reading }

related { Nonexpanding Cosmology Attempts to Oust Big Bang Theory }