Showing posts with label Light. Show all posts
Showing posts with label Light. Show all posts

Friday, November 7, 2008

British scientists shed light on mysterious dark matter that makes up most of our universe


It's a question that has baffled scientists for nearly a century - what is the mysterious 'invisible' matter that most of our universe is made of?

While stars and planets make up about 15 per cent of the universe's material, the remainder has been labelled 'dark matter' because it cannot be seen or detected by conventional instruments.

Now a team of cosmologists from Durham University believe they have found a way to detect it thanks to a computer simulation.

The researchers have developed a system that shows the formation and evolution of a galaxy like the Milky Way, which points to where scientists should look to spot dark matter.

The findings published in the journal Nature move researchers a step closer to solving one of science's great unanswered questions.

Carlos Frenk, a cosmologist at Durham University said: 'Discovering what dark matter is, is one of the most fundamental questions scientists can ask.'

'Uncovering the identity of the main component of the universe. That is what this is about.'
Dark matter does not reflect light nor normally shine, but astronomers infer its existence in galaxy clusters by observing how its gravity bends the light given off by even more faraway galaxies. They do not know what it is made of, but think it could be a kind of particle.

The international research team, known as the Virgo Consortium, looked at a dark matter halo - structures surrounding galaxies which weigh a trillion times more than the sun.

Their simulations showed how the galaxy's halo grew through a series of violent collisions between much smaller clumps of dark matter that emerged from the Big Bang.


In the densest part of the halo, the dark matter particles collide at high speed to produce a form of radiation called gamma rays. These gamma rays make the halo glow, giving scientists a potential way to detect dark matter.

The findings mean that NASA's Fermi Telescope should search in the part of the galaxy where the researchers predict dark matter should glow in 'a smoothly varying and characteristic pattern' where it is easier to see, the researchers said.

That location is near the sun, just off the center of the Milky Way, Frenk said.

'What we have shown through a gigantic simulation is where the gamma rays would come from,' he said.

'We have given a blueprint for people on where to look and how the signal should appear.'

Wednesday, October 22, 2008

Pictured: The mystery pink light that appeared over London

While a pink sky at night might be a shepherd's delight, London residents were left scratching their heads last night as a mysterious pink cloud drifted over the city.

Bemused bystanders in Mayfair craned their necks to witness the strange alien-like cloud that appeared for just under an hour at around 8:30pm.

It hovered over buildings before breaking up and slowly disappearing.

But after dismissing theories of UFOs and atmospheric phenomenons, the Met Office said the blob was likely to be nothing more than the lights of the city reflected in a cloud.

A spokesman said: "If you have very high cloud, as we did last night, you tend to get odd splodges of low cloud that will reflect the pink or sometimes orangey-pink lights of the city from all angles and stand out from the darkness of the sky.

"It can be truly spectacular to witness."

Did you see the mystery pink light? Let us know by leaving a reader comment at the bottom of the story.

 

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