Tag: Dark Energy

Supernovae Near & Far

A Supernova is the result of a massive star more than 10 times as massive as our sun reaching the end of it’s multi million year life and as it is so massive gravity makes the sun collapse in on itself. The implosion leads to an explosion so incredibly and unimaginably powerful that only the universe creating Big Bang is larger!

These enormous stars typically have a life of tens of millions of years, as opposed to our longer living smaller sedate sun that is middle aged at roughly five billion years old!

The super giant stars burn brightly living their lives in the fast lane. They consume massive amounts of hydrogen and helium gas at their cores. Other elements are formed near the core as the star tries to maintain nuclear fusion. Finally when iron is created at the core, fusion can no longer take place and gravity wins pulling the star’s incredible mass in on itself. The resulting titanic explosion creates most of the elements we know which are thrown deep into space forming vast clouds that will one day form other stars, planets and even life. Our sun, solar system of planets and us owe our existence to a long past supernova that created the elements, atoms etc., which created life billions of years ago.

Below are two articles about two stars that have gone supernova.
The nearest supernova for decades was discovered at an observatory about 3 miles (5 kms)from where we live!

UCL Observatory

Jean and I pass by this observatory regularly.

Supernova The supernova may be visible to stargazers through binoculars – and could grow brighter in coming weeks

An exploding star has been spotted in the night sky – the closest supernova to Earth that has been seen in decades.

The dramatic event happened 12 million light years away in Messier 82 – known as the cigar galaxy for its shape.

It was discovered by undergraduates during a telescope class at the University of London Observatory.

“One minute we’re eating pizza then five minutes later we’ve helped to discover a supernova. I couldn’t believe it,” said student Tom Wright.

“It reminds me why I got interested in astronomy in the first place.”

Supernova before and afterBefore and after: The supernova appears like a ‘new star’ in the lower image

The students from University College London were taking part in a 10-minute lesson with astronomer Dr Steve Fossey when they noticed what appeared to be a “new star”.

“We pointed the telescope at Messier 82 – it’s quite a bright galaxy, quite photogenic. But as soon as it came up on screen, it didn’t look right to me,” Dr Fossey told BBC News.

“We fired up another telescope, we got another frame – and that was when we knew it was a supernova.”

The “fluke” discovery led to a global scramble to acquire confirming images and spectra from the dazzling object.

It now been confirmed by the International Astronomical Union as a supernova – a violent blast of energy and light that is hurled out as a star dies.

It has taken 12 million years for the light to reach us. But though this may seem like a long way away, scientists say this is the closest supernova to be spotted since the late 1980s.

Scientists says it could grow even brighter over the coming weeks, before fading away.

If this happens, astronomers in the northern hemisphere may be able to spot it with binoculars, by looking between the Great Bear and the Little Bear.

Supernova ‘Mingus’ could shed light on dark energy

By Jason PalmerScience and technology reporter, BBC News, Long Beach, California

Supernova, artist's conceptionSupernovas are traditionally named after composers

Astronomers have spotted the most distant supernova ever seen.

Nicknamed “Mingus”, it was described at the  221st American Astronomical Society meeting in the US.

These lightshows of dying stars have been seen since ancient times, but modern astronomers use details of their light to probe the Universe’s secrets.

Ten billion light-years distant, Mingus will help shed light on so-called dark energy, the force that appears to be speeding up cosmic expansion.

Formally called SN SCP-0401, the supernova was something of a chance find in a survey carried out in part by the Supernova Cosmology Project (SCP) using the Hubble Space Telescope, first undertaken in 2004.

But the data were simply not good enough to pin down what was seen. As David Rubin of the University of California, Berkeley, lead author on the study, told the AAS meeting, “for a sense of brightness, this supernova is about as bright as a firefly viewed from 3,000 miles away”.

Further news had to wait until astronauts installed the Wide Field Camera 3 on the Hubble telescope in 2009 and again trained it on the candidate, which had – in an SCP tradition of naming supernovae after composers – already been named after jazz musician Charles Mingus.

“Unfortunately, it took the development of Wide Field Camera 3 to bring home what the [2004] measurements meant,” Mr Rubin told BBC News.

“The sensitivity is a few times better, which makes a huge difference, and we have a much cleaner image.”

Wide Field Camera 3 installationThe Wide Field Camera 3 enabled scientists to focus in on Mingus

The team went on to confirm that the supernova was in fact a Type 1a – a particular class of exploded star whose light occurs in such a regular way that it is known as a “standard candle”.

‘Bit of history’

What interests astronomers trying to find ever more distant Type 1a supernovae – distant both in space and in time – is the chance to compare them to better-known, more local supernovae.

“We were able to watch these changes in brightness and spectral features for an event that lasted just a few weeks almost 10 billion years ago,” said Saul Perlmutter, who leads the Supernova Cosmology Project.

Prof Perlmutter shared the 2011 Nobel Prize in Physics for work with Type 1a supernovae that proved our Universe is speeding up in its expansion.

Elucidating the mysterious force, “dark energy”, which has been invoked as the cause of the expansion, will require careful study of supernovae all the way back to the epoch of the earliest stars.

“We’re seeing two-thirds of the way back to the beginning of the Universe, and we’re getting a little bit of history where the physics of what makes a supernova explode have to all work out the same way there as they do near here,” he told the meeting.

Dark Ambitions

Supernova SN SCP-0401Supernova SN SCP-0401 fits into a wider story, Prof Frieman says

The meeting also heard from Joshua Frieman, director of the Dark Energy Survey – a five-year mission using the most powerful camera ever trained on the skies to get to the bottom of the dark matter mystery.

The phone-booth-sized Dark Energy Camera took it’s first cosmic  photos in Sept 2012 and will begin its formal mission in September this year, looking not only at supernovae but also at three other dark-energy signatures in the cosmos.

Prof Frieman told BBC News that the distant supernova result fits neatly into a story that he hoped the Dark Energy Survey would explore in great detail.

“What they’re doing is using the Hubble telescope to go really deep – we’re going to use the Dark Energy Survey to go very broad,” he explained to BBC News.

“They’re finding tens of supernovae at these high [distances], and we’re going to find thousands of supernovae not quite as deep. You really need both of those together to really make progress in trying to figure out why the Universe is speeding up.”

 

Do we exist in reality, or are we the ultimate computer simulation?

 

Galaxies in our universe..simulation a la Matrix!?

Cogito ergo sum = I think thererfore I am” as famously uttered by Descartes as part of his Dualist philosophy.

However are we the sum of our parts with an independant mind!?

Some scientists and physicists are devising complex computer simulations to see if we ourselves and the universe surrounding us is in fact the ultimate(for us) computer simulation.

Do we actually exist in an artificially created reality  as portrayed in the 1999 movie  ‘The Matrix’?

Hmm Do I take the red or blue pill? (as in the movie)

“I think therefore I am simulated”

In 2003, University of Oxford philosophy professor Nick Bostrom published a paper, “The Simulation Argument,” which argued that, “we are almost certainly living in a computer simulation.” Now, a team at Cornell University  in the US state that they have come up with a viable method for testing whether we’re all just a series of numbers in some ancient civilization’s computer game!
Researchers at the University of Washington agree with the testing method, saying it can be done. A similar proposal was put forth by German physicists in November.

So how, precisely, can we test whether we exist? Put simply, researchers are building their own simulated models, using a technique called lattice quantum chromodynamics. And while those models are currently able to produce models only slightly larger than the nucleus of an atom, University of Washington physics professor Martin Savage says the same principles used in creating those simulations can be applied on a larger scale.
“This is the first testable signature of such an idea,” Savage said. “If you make the simulations big enough, something like our universe should emerge.”

The testing method is far more complex. Consider the Cornell University explanation: “Using the historical development of lattice gauge theory technology as a guide, we assume that our universe is an early numerical simulation with unimproved Wilson fermion discretization and investigate potentially-observable consequences.”

More simply, if energy signatures in the simulations  match those in the universe at large, there’s a good chance we, too, exist within a simulation.

Towards Simulation

From the excellent and informative Space.com

Interestingly, one of Savage’s students takes the hypothesis further: If we stumble upon the nature of our existence, would we then look for ways to communicate with the civilization who created us?
University of Washington student Zohreh Davoudi says whoever made our simulated universe might have made others, and maybe we should “simply” attempt to communicate with those. “The question is, ‘Can you communicate with those other universes if they are running on the same platform?'” she asked.

Before you dismiss this idea as completely loony, the reality of such a Sim Universe might solve a lot of eerie mysteries about the cosmos. About two-dozen of the universe’s fundamental constants happen to fall within the narrow range thought to be compatible with life. At first glance it seems as unlikely as balancing a pencil on its tip. Jiggle these parameters and life as we know it would have never appeared. Not even stars and galaxies. This is called the Anthropic principle.

The discovery of dark energy in the universe over a decade ago further compounds the universe’s strangeness. This sort of “antigravity” pushing space-time apart is the closest thing there is to nothing and still is something. This energy from the vacuum of space is 60 orders of magnitude weaker that what would be predicted by quantum physics.The eminent cosmologist Michael Turner ranks dark energy as “the most profound mystery in all of science.”

We are also living at a very special time in the universe’s history where it switched gears from decelerating to accelerating under the push of dark energy. This begs the question “why me why now?” (A phrase popularly attributed to Olympic figure skater Nancy Kerrigan in 1994 when she was attacked and crippled by an opponent.)

If dark energy were slightly stronger the universe would have blown apart before stars formed. Any weaker and the universe would have imploded long ago. Its incredibly anemic value has been seen as circumstantial evidence for parallel universes with their own flavor of dark energy that is typically destructive. It’s as if our universe won the lottery and got all the physical parameters just right for us to exist.

Finally, an artificial universe solves the Fermi Paradox (where are all the space aliens?) by implying that we truly are alone in the universe. It was custom made for us by our far-future progeny.

Biblical creationists can no doubt embrace these seeming cosmic coincidences as unequivocal evidence for their “theory” of Intelligent Design (ID). But is our “God” really a computer programmer rather than a bearded old man living in the sky?