Finding a Fourth Dimension

Braneworld challenges Einstein’s general relativity. Image credit: NASA. Click to enlarge Scientists have been intrigued for years about the possibility that there are additional dimensions beyond the three we humans can understand. Now researchers from Duke and Rutgers universities think there’s a way to test for five-dimensional theory (4 spatial dimensions plus time) of gravity …

What’s Up This Week – May 29 – June 4, 2006

M83: “The Southern Pinwheel”. Image credit: Bill Schoening/NOAO/AURA/NSF. Click to enlarge. Greetings, fellow SkyWatchers! Let’s hope clear skies have returned to your area as we begin the week with a look at the incredible M83. As the Moon returns, we’ll study the features and be in for some excitement as it occults asteroid Vesta. Stay …

Before the Big Bang

Researchers have developed a model of a shrinking universe that existed prior to the Big Bang. Image credit: NASA. Click to enlarge The Big Bang describes how the Universe began as a single point 13.7 billion years ago, and has been expanding ever since, but it doesn’t explain what happened before that. Researchers from Penn …

Modifying Gravity to Account for Dark Matter

Researchers at the University of St. Andrews and the Free University of Brussels think they have a solution that “fine-tunes” Einstein’s groundbreaking theory of gravity to help account for the effect of dark matter. Dr Hong Sheng Zhao and Dr Benoit Famaey have created a new formula that allows the strength of gravity to vary over galactic distances, perfectly matching observations made by astronomers.

World’s Largest Telescope

Europeans have begun funding what will eventually become the world’s largest telescope: the Square Kilometre Array. The first step is a four-year study that will consult astronomers and engineers from around the world to decide what will make the best design. It will then be developed in stages, with parts coming operational over the next decade, and completion by 2020. Once complete, this extremely sensitive radio telescope will help probe the nature of dark matter, confirm Einstein’s predictions about relativity… and let us watch television shows broadcast from nearby stars.

More Einstein Rings Discovered

Astronomers have turned up 19 new gravitationally lensed quasars using photographs from the Hubble Space Telescope and the Sloan Digital Sky Survey (SDSS). 8 of these are what are known as “Einstein’s Rings”, where a nearby galaxy and a more distant quasar are perfectly lined up from our vantage point. The nearby galaxy acts as a lens to gravitationally focus the light from the quasar to magnify our view of it.

Best View of the Milky Way’s Core

Astronomers have used the National Science Foundation’s continent-wide Very Long Baseline Array (VLBA), to peer deeper into the heart of the Milky Way than ever before. This image brings astronomers tantalizingly close the supermassive black hole believed to lurk there called Sagittarius A*. The strong pull of this black hole should create a distinctive shadow on the surrounding material, which should be visible if astronomers can double the sensitivity of this instrument.

Will the Universe Expand Forever?

What is the nature of the mysterious dark energy which is accelerating expansion of the Universe? In a recent study published in the Physical Review Letters, physicists are proposing two scenarios: thawing and freezing. In thawing, the expansion of the Universe should eventually come to a stop, and maybe even reverse. In “freezing”, the acceleration should continue indefinitely. A new mission: the Joint Dark Energy Mission (JDEM) has been proposed by NASA and the US Department of Energy, and should be able to determine which of these two scenarios is correct.