Tag Archives: astrophysicist

Princeton astrophysicist Bhattacharjee leads team to create framework for an optimal fusion energy device

Stellarators, fusion facilities with a “twisty” design, have long played second fiddle to doughnut-shaped tokamaks that better confine the plasma that fuels fusion reactions. Now, in a development with major implications for the effort to replicate on Earth the fusion reactions that power the sun and stars to produce a virtually limitless supply of electricity, an international collaboration led by Princeton University has won a major private grant to create the framework for an optimum stellarator that combines the best features of both types of fusion reactors. (more…)

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Earthlike ‘Star Wars’ Tatooines may be common

Simulations dispute dogma: rocky planets may orbit many double stars

Luke Skywalker’s home in “Star Wars” is the desert planet Tatooine, with twin sunsets because it orbits two stars. So far, only uninhabitable gas-giant planets have been identified circling such binary stars, and many researchers believe rocky planets cannot form there. Now, mathematical simulations show that Earthlike, solid planets such as Tatooine likely exist and may be widespread. (more…)

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Time capsule of the Big Bang

Using one of the world’s premier telescopes, University of Minnesota astrophysicists Evan Skillman and Kristen McQuinn have discovered a priceless relic of the Big Bang in the Milky Way’s back yard.

They are part of an international team that found Leo P, a tiny galaxy in the constellation Leo that contains relatively few stars, but has large clouds of hydrogen and helium. The ratio of elements in those clouds is of great interest because it is believed to mirror conditions in the first few minutes after the Big Bang. (more…)

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What Do Sunsets Look Like From Other Planets?

A University of Exeter astrophysicist has shown what sunsets look like on planets outside our solar system.

He has worked out the colour of sunsets on two planets: HD 209458 b and HD 189733 b, known as ‘extrasolar planets’ because they are outside our solar system.

Extrasolar planets orbit stars, in a similar way to the Earth orbiting the Sun. Professor Frédéric Pont of the University of Exeter has used the extrasolar planets’ ‘transmission spectrum’, taken by the Hubble Space Telescope, to work out the colour of the ‘sunsets’ created by these stars.

Writing on the website ExoClimes.com, where he has posted the two sunset images he has produced, Professor Pont said: “Unlike its sister planet HD ’189, the planet HD ’209 (‘Osiris’) has a sunset that looks truly alien. The star is white outside the atmosphere, since its temperature is close to that of the Sun. It then acquires a bluish tinge as it sinks deeper, because the absorption by the broad wings of the neutral sodium lines (the spectral lines responsible for the gloomy orange of sodium street lighting) remove the red and orange from the star light. (more…)

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Berkeley Lab’s Saul Perlmutter wins Nobel Prize in Physics

BERKELEY, CA — Saul Perlmutter, an astrophysicist at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory and a professor of physics at the University of California at Berkeley, has won the 2011 Nobel Prize in Physics “for the discovery of the accelerating expansion of the universe through observations of distant supernovae.” Perlmutter heads the international Supernova Cosmology Project, which pioneered the methods used to discover the accelerating expansion of the universe, and he has been a leader in studies to determine the nature of dark energy.

Perlmutter shares the prize with Brian Schmidt and Adam Riess, leader of the High-z Supernova Search Team and first author of that team’s analysis, respectively, which led to their almost simultaneous announcement of accelerating expansion. (more…)

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Exeter Physicist Advances Early Universe Theory

*Research by a University of Exeter astrophysicist has helped to explain how the first stars and galaxies formed.*

*Research led by Professor Gilles Chabrier of the University of Exeter suggests that large magnetic fields were generated shortly after the Big Bang and played a key role in the formation of the first stars and galaxies.*

The international team of researchers, headed by Professor Chabrier and Dr Christoph Federrath of the Ecole Normale Supérieure de Lyon (France), used three-dimensional computer simulations to make their discovery. Their simulations show that even under extreme physical conditions, magnetic fields are efficiently amplified by turbulent flows. The findings are now published in the journal Physical Review Letters.

Both the gas between the stars in a galaxy and the medium between galaxies are magnetised. However, little is known so far about how these magnetic fields, which can be seen with telescopes, actually came about. Now, the international research team has proposed an answer. (more…)

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Why Some Planets Orbit the Wrong Way; Extrasolar Insights into Our Solar System

More than 500 extrasolar planets–planets that orbit stars other than the sun–have been discovered since 1995. But only in the last few years have astronomers observed that in some of these systems, the star is spinning one way and the planet is orbiting that star in the opposite direction.

“That’s really weird, and it’s even weirder because the planet is so close to the star,” said Frederic A. Rasio, a theoretical astrophysicist at Northwestern University. “How can one be spinning one way and the other orbiting exactly the other way? It’s crazy. It so obviously violates our most basic picture of planet and star formation.” (more…)

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