Dark energy -- 10 years on

Nov 30, 2007

Three quarters of our universe is made up of some weird, gravitationally repulsive substance that was only discovered ten years ago – dark energy. This month in Physics World, Eric Linder and Saul Perlmutter, both at the University of California at Berkeley, reveal how little we know about dark energy and describe what advances in our knowledge of dark energy we can expect in the coming decade from a series of planned space missions.

Perlmutter was the leader of one of the two separate teams of astrophysicists who concluded, from watching distant supernovae, that the cosmic expansion was accelerating and not slowing under the influence of gravity, as was previously thought. The two teams' finding confirmed just how little we know about our universe.

The two teams' discovery has led to the creation of the "concordance model" of the universe, which states that 75 per cent of our universe is made up of dark energy, 21 per cent of dark matter, another substance we know little about, with only a remaining four per cent being made up of matter that we do understand. The most conventional explanation is that dark energy is some kind of "cosmological constant" that arises from empty space not being empty, but having an energy as elementary particles pop in and out of existence.

Since the first evidence for the accelerating universe was made public in early 1998, astrophysicists have provided further evidence to shore up the findings and advances in the measurement methods bode well for increasing our understanding in the future.

Galaxies and the cosmic background hold some significant clues. Equipment that can make a more robust comparison between galaxy patterns across the sky and investigate temperature fluctuations in the cosmic microwave background, helping trace the pattern of galaxy formation, is being made available. Methods for further observation of supernovae are expanding and improving too.

Eric Linder and Saul Perlmutter write, “The field of dark energy is very young and we may have a long and exciting period of exploration ahead before it matures.”

The December issue also includes reporting from Robert P Crease, historian at the Brookhaven National Laboratory, US, on the difficulty of deciding who should gain credit for the discovery of the accelerating universe and comment from Lawrence M Krauss, director of the Center for Education and Research in Cosmology and Astrophysics at Case Western Reserve University, US, on the possibility that we may never be able to tell if dark energy is a cosmological constant or something more exotic still.

Link: physicsworld.com

Source: Institute of Physics

Explore further: New filter could advance terahertz data transmission

add to favorites email to friend print save as pdf

Related Stories

How can space travel faster than the speed of light?

Feb 23, 2015

Cosmologists are intellectual time travelers. Looking back over billions of years, these scientists are able to trace the evolution of our Universe in astonishing detail. 13.8 billion years ago, the Big Bang ...

How fast is the universe expanding?

Feb 10, 2015

The Universe is expanding, but how quickly is it expanding? How far away is everything getting from everything else? And how do we know any of this anyway?

Recommended for you

New filter could advance terahertz data transmission

Feb 27, 2015

University of Utah engineers have discovered a new approach for designing filters capable of separating different frequencies in the terahertz spectrum, the next generation of communications bandwidth that ...

The super-resolution revolution

Feb 27, 2015

Cambridge scientists are part of a resolution revolution. Building powerful instruments that shatter the physical limits of optical microscopy, they are beginning to watch molecular processes as they happen, ...

A new X-ray microscope for nanoscale imaging

Feb 27, 2015

Delivering the capability to image nanostructures and chemical reactions down to nanometer resolution requires a new class of x-ray microscope that can perform precision microscopy experiments using ultra-bright ...

Top-precision optical atomic clock starts ticking

Feb 26, 2015

A state-of-the-art optical atomic clock, collaboratively developed by scientists from the University of Warsaw, Jagiellonian University, and Nicolaus Copernicus University, is now "ticking away" at the National ...

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

holoman
5 / 5 (1) Nov 30, 2007
Why not say we know nothing, we know nothing.

The whole article is a guessing game without real proof.
TimESimmons
3 / 5 (2) Dec 01, 2007
We don't know nothing. We understand. At least I do. And I'm getting frustrated trying to explain it to you lot. See what he says above "weird, gravitationally repulsive substance" It's simple.

http://www.presto...ndex.htm

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.