Out There

January 29, 2014

The Search for Dark Matter

Out There: Episode #6

As we learned last week in Discovering Dark Matter, since the 1930s scientists have been seeking answers about unseen mass in the universe. We know that the gravitation of dark matter has an enormous effect on galaxies, and we also know that it may be made up of weakly interacting particles. But how do researchers search for something that's invisible? James Buckley, professor of physics, has spent part of his career hunting for neutralinos, a yet-undiscovered type of particle that may hold the answer to the dark-matter mystery. Buckley describes the evidence for the existence of neutralinos, the methods he uses to seek them out, and how he first became interested in the "dark and violent" side of the universe

 

January 22, 2014

Discovering Dark Matter

Out There: Episode #5

Back in the early 1930s, astronomer Fritz Zwicky discovered a problem. Zwicky studied galaxy clusters, which can contain hundreds to thousands of galaxies loosely bound together by gravity. While examining one such cluster, he realized that the visible material within the galaxies did not have enough mass to hold the cluster together. As a result, he inferred that some dark, unseen matter must exist. Decades later, Ramanath Cowsik theorized about the source of this extra gravitational force. Cowsik, who now directs the McDonnell Center for the Space Sciences, describes the history of dark matter and shares how his discovery changed the way scientists think about this invisible force in the universe.

January 15, 2014

Beautifully Bright Black Holes

Out There: Episode #4

Black holes - pools of gravity so powerful that even light can't escape them - remain some of the most mysterious objects in the universe. Yet, though black holes themselves are invisible, the matter around them is not. In fall 2014, Henric Krawczynski, professor of physics at Washington University in St. Louis, will use an instrument called X-Calibur to study two "beautifully bright" black holes visible from Earth's northern hemisphere. By measuring the polarization of X-rays emitted from material near the black holes, X-Calibur will help Krawczynski and his colleagues investigate questions that have perplexed scientists since Albert Einstein first proposed his Theory of General Relativity.

December 11, 2013

Catching Cosmic Rays

Out There: Episode #3

On December 9, 2012, a balloon the size of a football field ascended nearly 140,000 feet into the Antarctic sky. The balloon carried Super-TIGER, a two-ton instrument built to detect cosmic rays. Drs. W. Robert Binns and Martin Israel, who head the cosmic ray group within the physics department at Washington University in St. Louis, describe this record-breaking experiment and explain why they seek to know more about the origins of cosmic rays.

December 4, 2013

Studying Stardust

Out There: Episode #2

Christine Floss, research professor in the physics department at Washington University in St. Louis, spends her time investigating microscopic specks of dust that have remained unchanged since before the formation of the solar system some 4.5 billion years ago. These presolar grains help researchers like Floss answer questions about the formation of elements, the solar system, and the universe as a whole. Floss describes how she and her students search for presolar grains in ancient meteorites, why tiny grains of silica are particularly fascinating, and how as an undergraduate geology major she first became hooked on outer space.

November 27, 2013

Lunar Mysteries

Out There: Episode #1

What questions have yet to be answered about the Moon? Bradley Jolliff, professor of earth and planetary sciences at Washington University in St. Louis, describes how lunar samples and orbiters continue to provide insights into the geologic history of Earth's closest neighbor. Jolliff, who works with the Mars rover Opportunity, also shares his dreams of a future lunar rover that would visit sites that continue to puzzle scientists, including the immense South Pole-Aitken Basin and the icy, permanently shadowed lands near the Moon's poles.