JPL. Meteorite. Sun-Earth Day - Technology Through Time - #50 Ancient Sunlight. The 8-minute travel time to Earth by sunlight hides a thousand-year journey that actually began in the core. Sunrises are seen with light created thousands of years ago in the core of the sun. Sunlight is produced through nuclear reactions in the sun's core. Originally born as energetic gamma rays, after billions of collisions with matter, this radiation reaches the surface and escapes into space. How old is sunlight by the time it reaches the surface? Most textbooks say that it takes light between 100,000 years and 50 million years to escape. You would be surprised to know that this simple, and very popular, question seems to be without a firm answer! The reason has a lot to do with the assumptions that textbook authors use in making the calculation. Once a photon of light is born, it travels at a speed of 300,000 km/sec until it collides with a charged particle and is diverted in another direction.
References: Anniversary of a cosmic blast. Five years ago today — on December 27, 2004 — the Earth was attacked by a cosmic blast. The scale of this onslaught is nearly impossible to exaggerate. The flood of gamma and X-rays that washed over the Earth was detected by several satellites designed to observe the high-energy skies. RHESSI, which observes the Sun, saw this blast. INTEGRAL, used to look for gamma rays from monster black holes, saw this blast. The newly-launched Swift satellite, built to detect gamma-ray bursts from across the Universe, not only saw this blast, but its detectors were completely saturated by the assault of energy… even though Swift wasn’t pointed anywhere near the direction of the burst! In other words, this flood of photons saturated Swift even though they had to pass through the walls of the satellite itself first! It gets worse. So what was this thing? Astronomers discovered quickly just what this was, though when they figured it out they could scarcely believe it.
See the pulsations in the plot? Welcome to 100 Hours of Astronomy. Discovered: Cosmic Rays from a Mysterious, Nearby Object. + Play Audio | + Download Audio | + Join mailing list Nov. 19, 2008: An international team of researchers has discovered a puzzling surplus of high-energy electrons bombarding Earth from space. The source of these cosmic rays is unknown, but it must be close to the solar system and it could be made of dark matter.
Their results are being reported in the Nov. 20th issue of the journal Nature. "This is a big discovery," says co-author John Wefel of Louisiana State University. Right: An artist's concept of cosmic rays hitting Earth's upper atmosphere. Galactic cosmic rays are subatomic particles accelerated to almost light speed by distant supernova explosions and other violent events. To study the most powerful and interesting cosmic rays, Wefel and colleagues have spent the last eight years flying a series of balloons through the stratosphere over Antarctica. Above: ATIC high-energy electron counts. Why must the source be nearby? High-energy electrons are therefore local. Author: Dr. Hubble Takes First Visible Light Image of Extrasolar Planet | Universe Today.
Want to stay on top of all the space news? Follow @universetoday on Twitter Fomalhaut and orbiting planet. Credit: NASA, ESA and P. Kalas (University of California, Berkeley, USA) Persistence has paid off for astronomer Paul Kalas. After eight years and taking repeated photographs with the Hubble Space Telescope of a nearby star, he finally has what he and many astronomers have been striving for: the first visible-light snapshot of a planet outside our solar system. “The gravity of Fomalhaut b is the key reason that the vast dust belt surrounding Fomalhaut is cleanly sculpted into a ring and offset from the star,” Kalas said. Check out this video from ESA about the discovery: “It will be hard to argue that a Jupiter-mass object orbiting an A star like Fomalhaut is anything other than a planet,” said coauthor James R.
Fomalhaut annotated. “I nearly had a heart attack at the end of May when I confirmed that Fomalhaut b orbits its parent star,” Kalas said. First Image of Another Multi-Planet Solar System | Universe Today. Want to stay on top of all the space news? Follow @universetoday on Twitter Here’s what we’ve all been waiting for: for the first time, astronomers have taken pictures of a multi-planet solar system, much like ours, orbiting another star. This coincides with announcement of the first visible light image of an extrasolar planet taken by the Hubble Space Telescope. This new solar system orbits a dusty young star named HR8799, which is 140 light years away and about 1.5 times the size of our sun. Three planets, roughly 10, 10 and 7 times the mass of Jupiter, orbit the star. “We’ve been trying to image planets for eight years with no luck and now we have pictures of three planets at once,” said Bruce Macintosh, an astrophysicist from Lawrence Livermore National Laboratory.
Astronomers have known for a decade through indirect techniques that the sun was not the only star with orbiting planets. “But we finally have an actual image of an entire system,” Macintosh said. Mysterious New 'Dark Flow' Discovered in Space. As if the mysteries of dark matter and dark energy weren't vexing enough, another baffling cosmic puzzle has been discovered. Patches of matter in the universe seem to be moving at very high speeds and in a uniform direction that can't be explained by any of the known gravitational forces in the observable universe. Astronomers are calling the phenomenon "dark flow. " The stuff that's pulling this matter must be outside the observable universe, researchers conclude. When scientists talk about the observable universe, they don't just mean as far out as the eye, or even the most powerful telescope, can see. In fact there's a fundamental limit to how much of the universe we could ever observe, no matter how advanced our visual instruments.
The universe is thought to have formed about 13.7 billion years ago. So even if light started travelling toward us immediately after the Big Bang, the farthest it could ever get is 13.7 billion light-years in distance. Mysterious motions Inflationary bubble. Sloan Digital Sky Survey. Press Release: Spitzer Captures Stellar Coming of Age in Our Galaxy. Science Journal. Near-Earth Object Program. Elementary Einstein. At the beginning of the twentieth century, Albert Einstein revolutionized the way scientists think about space and time.
"Elementary Einstein" takes you on a tour of his surprising ideas and their coolest applications. In his special theory of relativity, Einstein showed that time and length are not as absolute as everyday experience would suggest: Moving clocks run slower, and moving objects are shorter. Those are just two of the unusual properties of Einstein's world! Another consequence of special relativity is the most famous formula of all: E=mc², stating that two physical quantities which physicists had defined separately, namely energy and mass, are in fact equivalent. In Einstein's general theory of relativity, space and time become even more flexible. "Your mileage may vary," and so may the time intervals you measure, depending on where and when you are. This flexibility has an analogue in the geometry of surfaces like that of a sphere - there is a curvature of space and time.
WIKISKY.ORG. Eta Carinae :: 20 Jun 07. Eta Carinae: New View of Doomed Star Credit: X-ray: NASA/CXC/GSFC/M.Corcoran et al.; Optical: NASA/STScI Eta Carinae is a mysterious, extremely bright and unstable star located a mere stone's throw - astronomically speaking - from Earth at a distance of only about 7,500 light years. The star is thought to be consuming its nuclear fuel at an incredible rate, while quickly drawing closer to its ultimate explosive demise. When Eta Carinae does explode, it will be a spectacular fireworks display seen from Earth, perhaps rivaling the moon in brilliance. Its fate has been foreshadowed by the recent discovery of SN2006gy, a supernova in a nearby galaxy that was the brightest stellar explosion ever seen. Eta Carinae, a star between 100 and 150 times more massive than the Sun, is near a point of unstable equilibrium where the star's gravity is almost balanced by the outward pressure of the intense radiation generated in the nuclear furnace.
Bad Astronomy Blog » Eta Car: tick tock, tick tock. A new paper just published in the prestigious Astrophysical Journal makes a stunning claim: There are 10 times as many galaxies in the Universe as we previously thought. At least. The total number comes in at about 2 trillion of them. Now, let me be clear. This doesn’t meant the Universe is 10 times bigger than we thought, or there are 10 times as many stars. I’ll explain—I mean, duh, it’s what I do—but to cut to the chase, what they found is that there are lots of teeny, faint galaxies very far away that have gone undetected. So instead of being in a smaller number of big galaxies, stars are divvied up into a bigger number of smaller ones. What the astronomers did was look at extremely deep images of the Universe taken in surveys, for example the Hubble Ultra Deep Field. That’s a lot of galaxies. Surveys like the UDF are limited. The astronomers who did this research had an interesting problem. The answer is two-fold.
Those numbers change with distance. NASA,ESA, H. A whole lot.