Asteroid might hit Mars

Alicia Chang, Associated Press, reports:

A newly discovered hunk of space rock has a 1 in 75 chance of slamming into the Red Planet on Jan. 30, scientists said Thursday.

"These odds are extremely unusual. We frequently work with really long odds when we track ... threatening asteroids," said Steve Chesley, an astronomer with the Near Earth Object Program at NASA's Jet Propulsion Laboratory.

The asteroid, known as 2007 WD5, was discovered in late November and is similar in size to an object that hit remote central Siberia in 1908, unleashing energy equivalent to a 15-megaton nuclear bomb and wiping out 60 million trees....

..."We know that it's going to fly by Mars and most likely going to miss, but there's a possibility of an impact," he said.

If the asteroid does smash into Mars, it will probably hit near the equator close to where the rover Opportunity has been exploring the Martian plains since 2004. The robot is not in danger because it lies outside the impact zone. Speeding at 8 miles a second, a collision would carve a hole the size of the famed Meteor Crater in Arizona....

RIA Novosti (Russia) notes:

"It will not influence the Earth in any way," {Sergei} Smirnov {Russian Academy of Science spokesman} said....

...The scientist said that if the collision takes place, it will not be visible without high-definition telescopes, but would still provide valuable scientific data: "The object is sure to change its flight path, and this will considerably enrich our knowledge of the mass and density of asteroids."

He also said a large asteroid was expected to pass near Earth in 2028 which could cause a major disaster if it collides with the planet.

Time may be literally running out

Tom Chivers and Roger Highfield on the Telegraph have a great article on the new theories about time from Professor José Senovilla, Marc Mars and Raül Vera of the University of the Basque Country, Bilbao, and University of Salamanca, Spain: time could cease to be.

...The team's proposal, which will be published in the journal Physical Review D, does away altogether with dark energy. Instead, Prof Senovilla says, the appearance of acceleration is caused by time itself gradually slowing down, like a clock that needs winding.

"We do not say that the expansion of the universe itself is an illusion," he explains. "What we say it may be an illusion is the acceleration of this expansion - that is, the possibility that the expansion is, and has been, increasing its rate."

Instead, if time gradually slows "but we naively kept using our equations to derive the changes of the expansion with respect of 'a standard flow of time', then the simple models that we have constructed in our paper show that an "effective accelerated rate of the expansion" takes place."...

...If time is indeed slowing down, so that according to this new suggestion our solitary time dimension is slowly turning into a new space dimension, then the far-distant, ancient stars seen by cosmologists would therefore, from our perspective, look as though they were accelerating.

"Our calculations show that we would think that the expansion of the universe is accelerating," says Prof Senovilla.

The group bases its idea on one particular variant of superstring theory, a so called theory of everything, in which our universe is confined to the surface of a membrane, or brane, floating in a higher-dimensional space, known as the "bulk".

In some number of billions of years, time would cease to be time altogether - and everything will stop.

"Then everything will be frozen, like a snapshot of one instant, forever," Prof Senovilla tells New Scientist magazine. "Our planet will be long gone by then."

However, he adds that the team is only assuming there is one dimension of time....

Roger Highfield on the Telegraph reports on Itzhak Bars' theory of two dimensions of time:

...Time is no longer a simple line from the past to the future, in a four dimensional world consisting of three dimensions of space and one of time. Instead, the physicist envisages the passage of history as curves embedded in a six dimensions, with four of space and two of time.

"There isn't just one dimension of time," Itzhak Bars of the University of Southern California in Los Angeles tells New Scientist.

"There are two. One whole dimension of time and another of space have until now gone entirely unnoticed by us."

Bars claims his theory of "two time physics", which he has developed over more than a decade, can help solve problems with current theories of the cosmos and, crucially, has true predictive power that can be tested in a forthcoming particle physics experiment....

Here is Bars' webpage - http://physics1.usc.edu/%7Ebars/research.html#2T