Uffe Gråe Jørgensen explains that you need to have two stars that lie on a straight line in relation to us here on Earth. Then the light from the background star is amplified by the gravity of the foreground star, which thus acts as a magnifying glass. When the stars pass close by each other in the sky, astronomers can observe the light from the background star first increase and then decrease again. If there is a planet around the foreground star, there might be a little extra bump on the light curve.
Heavens
GAINESVILLE, Fla. -- Using data from NASA's Kepler mission, a team that includes a University of Florida astronomer has discovered two new planets orbiting double star systems, something that had never been seen until last September.
The newly confirmed planets, called Kepler-34b and Kepler-35b, will be announced in Wednesday's online edition of the journal Nature, said Eric B. Ford, UF associate professor of astronomy. William F. Welsh, associate professor at San Diego State University, is the lead author on the paper.
Tropical Storm Heidi is forecast to make landfall today along the Pilbara coast of Western Australia as warnings pepper the coast. NASA's Aqua satellite passed overhead early in the day and captured a visible image showing Heidi's center still north of the Pilbara coast, while her outer bands continue to bring rainfall and gusty winds to coastal residents.
Peering deep inside the hub of the neighboring Andromeda galaxy, NASA's Hubble Space Telescope has uncovered a large, rare population of hot, bright stars.
Blue is typically an indicator of hot, young stars. In this case, however, the stellar oddities are aging, sun-like stars that have prematurely cast off their outer layers of material, exposing their extremely blue-hot cores.
Astronomers were surprised when they spotted these stars because physical models show that only an unusual type of old star can be as hot and as bright in ultraviolet light.
A new Hubble Space Telescope image centers on the 100-million-solar-mass black hole at the hub of the neighboring spiral galaxy M31, or the Andromeda galaxy, the only galaxy outside the Milky Way visible to the naked eye and the only other giant galaxy in the local group.
This is the sharpest visible-light image ever made of the nucleus of an external galaxy.
Astronomers using the partially completed ALMA observatory have found compelling evidence for how star-forming galaxies evolve into 'red and dead' elliptical galaxies, catching a large group of galaxies right in the middle of this change.
Humans are considered the hosts for spreading epidemics. The speed at which an epidemic spreads is now better understood thanks to a new model accounting for the provincial nature of human mobility, according to a study published in EPJ B¹. The research was conducted by a team lead by Vitaly Belik from the Massachusetts Institute of Technology, USA, who is also affiliated with the Max Planck Institute for Dynamics and Self-Organization, Germany.
CAMBRIDGE, Mass. -- Just outside Seville, in the desert region of Andalucia, Spain, sits an oasis-like sight: a 100-meter-high pillar surrounded by rows of giant mirrors rippling outward. More than 600 of these mirrors, each the size of half a tennis court, track the sun throughout the day, concentrating its rays on the central tower, where the sun's heat is converted to electricity — enough to power 6,000 homes.
It takes the highest levels of concentration for emergency workers to fight their way through smoke-filled buildings wearing breathing apparatus and protective suits. What is the location of the casualties? Where is the nearest exit, in case the crews need to get to safety? Up to now, they have used ropes to retrace their steps, but these can get caught up or wrap themselves around obstacles. Chalk is used to mark which rooms have already been searched, but these markings are often difficult to see through the smoke.
LIVERMORE, Calif. — Sandia National Laboratories computer scientist Casey Deccio has developed a visualization tool known as DNSViz to help network administrators within the federal government and global IT community better understand Domain Name System Security (DNSSEC) and to help them troubleshoot problems. (To see a short video of Deccio discussing the DNSViz tool, go to http://bit.ly/wqs26q).
After more than three years in space, NASA's Fermi Gamma-ray Space Telescope is extending its view of the high-energy sky into a largely unexplored electromagnetic range. Today, the Fermi team announced its first census of energy sources in this new realm.
Using observations from NASA's Rossi X-ray Timing Explorer (RXTE) satellite and the National Science Foundation's (NSF) Very Long Baseline Array (VLBA) radio telescope, an international team of astronomers has identified the moment when a black hole in our galaxy launched super-fast knots of gas into space.
Racing outward at about one-quarter the speed of light, these "bullets" of ionized gas are thought to arise from a region located just outside the black hole's event horizon, the point beyond which nothing can escape.
Using NASA's Hubble Space Telescope, astronomers have uncovered a cluster of galaxies in the initial stages of development. It is the most distant such grouping ever observed in the early universe.
In a random sky survey made in near-infrared light, Hubble found five tiny galaxies clustered together 13.1 billion light-years away. They are among the brightest galaxies at that epoch and very young -- existing just 600 million years after the big bang.
The stars we see today weren't always as serene as they appear, floating alone in the dark of night. Most stars, likely including our sun, grew up in cosmic turmoil — as illustrated in a new image from NASA's Spitzer Space Telescope.
Astronomers have gained an important clue about a ubiquitous cosmic process by pinpointing the exact moment when gigantic "bullets" of fast-moving material were launched from the region surrounding a black hole. They made this breakthrough by using the ultra-sharp radio "vision" of the National Science Foundation's Very Long Baseline Array (VLBA), along with NASA's Rossi X-ray Timing Explorer (RXTE) satellite, to study an outburst from a system including a black hole and its companion star in 2009.