AAAS News Release - "SCIENCE: Dust Scooped From Asteroid Confirms Source of Earth-Bound Meteorites" Researchers got their first up-close look at dust from a small, stony asteroid after the Hayabusa spacecraft scooped up the dust from the asteroid’s surface and brought it back to Earth. Analysis of the dust particles, detailed in the 26 August issue of Science, confirms a long-standing suspicion: Most common meteorites found here on Earth, known as ordinary chondrites, are born from these stony, or S-type, asteroids. Since chondrites are among the most primitive objects in the solar system, the discovery also means that these asteroids have been recording a long and rich history of early solar system events. “Science is very excited and pleased to be presenting these important scientific analyses,” said Brooks Hanson, the journal’s deputy editor for the physical sciences. “The first samples that researchers collected beyond Earth were from the moon, and the first analyses of those samples were also published in Science. [Video © Science/AAAS] Links
Scientists Now Know: We're From Sagittarius Dwarf Galaxy! Scientists Now Know: We're Not From Here! Summary & comments by Dan Eden for Viewzone "This first full-sky map of Sagittarius shows its extensive interaction with the Milky Way," Majewski said. The study's map of M giants depicts 2 billion years of Sagittarius stripping by the Milky Way, and suggests that Sagittarius has reached a critical phase in what had been a slow dance of death. "After slow, continuous gnawing by the Milky Way, Sagittarius has been whittled down to the point that it cannot hold itself together much longer," said 2MASS Science Team member and study co-author Martin Weinberg of the University of Massachusetts. Does this mean we are at a unique moment in the life of our galaxy? "Whenever possible, astronomers appeal to the principle that we are not at a special time or place in the universe," Majewski said. On the other hand, Majewski and his colleagues have been surprised by the Earth's proximity to a portion of the Sagittarius debris. Implications in Global Warming?
The James Webb Space Telescope About Webb's Orbit The James Webb Space Telescope will observe primarily the infrared light from faint and very distant objects. But all objects, including telescopes, also emit infrared light. To avoid swamping the very faint astronomical signals with radiation from the telescope, the telescope and its instruments must be very cold. Therefore, Webb has a large shield that blocks the light from the Sun, Earth, and Moon, which otherwise would heat up the telescope, and interfere with the observations. The L2 orbit is an elliptical orbit about the semi-stable second Lagrange point . In three of the solutions found by Lagrange, the bodies are in line (L1, L2, and L3); in the other two, the bodies are at the points of equilateral triangles (L4 and L5). In the case of Webb, the 3 bodies involved are the Sun, the Earth and the Webb. Other infrared missions have selected an L2 orbit, like WMAP and H2L2. Here are a few graphics that illustrate how far away Webb will be.
Lunar Eclipse: Watch It Live on YouTube At 11:20 a.m. PT Wednesday, a total, 100-minute-long lunar eclipse will be visible in South America, Europe, Africa, Asia and Australia. If you're not from those parts, Google and Slooh have prepared a myriad of options that let you enjoy the lunar eclipse from the relative safety of your couch. Perhaps the simplest way to watch the lunar eclipse is to tune into the live streaming video on Google's official YouTube channel. You can also follow the event on Slooh's mission interface, together with narration from astronomers, or you can watch it from the Sky layer in Google Earth by downloading this .kml file. The Fermi Gamma-ray Space Telescope Facebook Iberian Peninsula at Night The city lights of Spain and Portugal define the Iberian Peninsula in this photograph from the International Space Station (ISS). Several large metropolitan areas are visible, marked by their relatively large and brightly lit areas, including the capital cities of Madrid, Spain—located near the center of the peninsula’s interior—and Lisbon, Portugal—located along the southwestern coastline. The ancient city of Seville, visible to the north of the Strait of Gibraltar, is one of the largest cities in Spain. The network of smaller cities and towns along the coastline and in the interior attest to the extent of the human presence on the Iberian landscape. The Iberian Peninsula is the southwestern-most of the European peninsulas (together with the Italian and Balkan peninsulas), and includes the Principality of Andorra, as well as the Kingdom of Spain and the Portuguese Republic. Instrument(s): ISS - Digital Camera
The Sounds of Pulsars A pulsar is a highly magnetised neutron star, with a radius of 10-15 km, having somewhat greater mass than the Sun which has a radius of approximately 1 million km. Radiation is beamed out along the magnetic poles and pulses of radiation are received as the beam crosses the Earth, in the same manner as the beam from a lighthouse causes flashes. Being enormous cosmic flywheels with a tick attached, they make some of the best clocks known to mankind. These sounds directly correspond to the radio-waves emitted by the brightest pulsars in the sky as received by some of the largest radio telescopes in the world. To listen to the pulses of a radio pulsar, click on its arrow icon.
The Earth's most powerful telescope goes online next week The Moon is a particularly good place to do neutrino physics because of the the cosmic ray backgrounds underground. On Earth, at sea level, cosmic rays are mostly due to high-energy protons interacting with the upper atmosphere. These collisions create a lot of pions. Because the atmosphere isn't very dense, these pions don't slow down very quickly, and so when they decay into muons the muons are still extremely energetic. Muons are highly penetrating particles, so even when we build neutrino detectors kilometres underground we have to deal with a very significant cosmic-ray muon background signal. On the Moon, with no atmosphere to speak of, the primary cosmic-ray protons smack into solid rock, so the pions are created in that very dense medium and almost all of them slow way down before decaying, so the muons only have the muons are much lower energy and penetrate a very short distance.