Archive for June, 2010
ESO Eyes R Coronae Australis
Today, the European Southern Observatory (ESO) released new images taken in the vicinity of a star known as R Coronae Australis. Near this star there is a reflection nebula. A reflection nebula is a dust cloud which scatters the light of nearby stars due to the amount of dust in the vicinity of the gas cloud, which like our atmosphere appears bluish in color to the human eye. Learn more about all the nebulae near R Coronae Australis online now here.
ESA Releases Soil Moisture and Ocean Salinity Data
The European Space Agency (ESA) today revealed to the public, for the first time, some of the science data coming from the ESA Soil Moisture and Ocean Salinity (SMOS) satellite launched in November 2009. As its name implies, the SMOS mission is to “to gather data on moisture in the surface layers of soil and salt in the surface of the oceans.” ESA scientists hope that this will “improve our understanding of the water cycle and help advance weather and climate studies.” Learn more about the SMOS spacecraft and its first science data online now here.
ESA Celebrates Microsatellite Proba-2 Achievements
In November of 2009, the European Space Agency (ESA) launched a uniquely small satellite, called a microsatellite, to observe the Sun. The spacecraft is called Proba-2 and it has been acquiring science data since February of this year. In a conference last week, ESA scientists presented the first data from Proba-2. Among the presentations was a video of the Sun made by Proba-2 highlighting coronal mass ejections (CME). See the video released to the public today (and more) captured by Proba-2 online now here.
ESA Releases First GOCE Global Model
The European Space Agency (ESA) announced today that it was releasing the first global gravitational field model of the Earth based upon its satellite called GOCE (Gravity field and steady-state Ocean Circulation Explorer). These data are important to scientists because they are “a crucial reference for accurately measuring ocean circulation, sea-level change and ice dynamics – all affected by climate change.” Learn more about this Earth observing satellite model online now here.
ESO Peers at Exoplanet Gas Giant Storm
The European Southern Observatory (ESO) announced last week that it had detected an atmospheric storm on a gas giant exoplanet (about 60% the mass of Jupiter) orbiting a star in the constellation Pegasus. The planet is known as HD209458b and is about 150 light years distant from our own solar system. As noted by the team leader Dr. Ignas Snellen: “HD209458b is definitely not a place for the faint-hearted. By studying the poisonous carbon monoxide gas with great accuracy we found evidence for a super wind, blowing at a speed of 5000 to 10 000 km per hour.” Learn more about this gas giant exoplanet online now here.
Hunting Gamma-ray Bursts
The Swift Satellite
Data from the Swift satellite's ultraviolet/optical and x-ray telescopes show one of the most distant gamma-ray bursts ever detected. It's so distant that the star that died to create it exploded when the universe was about 630 million years old. Credit: NASA/Swift/Stefan Immler
In the June edition of The Astronomer’s Universe, I talk about gamma-ray bursts with Dr. Dale Frail of the Very Large Array (VLA) in New Mexico. Gamma-ray bursts (commonly referred to as GRBs) are strong blasts of gamma rays that astronomers have detected from nearly every direction in the universe. The first ones were detected by a military satellite back in the early days of the space age, and nobody knew quite what to make of them. Today, we have satellites in constant watch for GRBs (as they are called), including NASA’s Swift mission.
Swift is an international mission with scientists from U.S., Italy, and the United Kingdom participating. It has three main instrument packages that let it study GRBs in great detail. In the six years since its launch, Swift has seen more than 500 GRBs and it continues to monitor the skies constantly for more of these outbursts.
What instruments does Swift use to watch for these titanic outbursts that appear so briefly in our skies? The first is the so-called Burst Alert Telescope (BAT). It looks f0r bursts in the energy range of 15 to 150 keV (shorthand for kilo-electron volt, a measure of energy). The BAT calculates the position of the burst that it sees and if the burst is strong enough, the whole spacecraft slews around to take a closer look.
Swift also has an x-ray telescope and UV/optical telescope, both of which study the afterglows of the gamma-ray burst in their respective wavelength ranges. A GRB is going to have a certain amount of its radiation in the optical, ultraviolet, and x-ray ranges, as well. Studying all four (gamma, x-ray, optical, and ultraviolet) gives the most complete “picture” of the GRB.
The positions of GRBs that Swift finds are relayed to ground-based observatories so that astronomers can continue to study the afterglows of GRBs long after the inital burst has faded away. The data that astronomers get from Swift and all the other instruments used to monitor the GRBs (such as the radio telescopes of the VLA), are going a long way toward giving astronomers a much fuller picture of just what causes these monster explosions in distant space.
New Galaxy Velocity Measurements Raise Questions
In a pre-print released today, astronomers have released measurements of the velocities of galaxies based upon data from the Sloan Digital Sky Survey (SDSS). These results bring into question the currently accepted values for the expansion of the universe, and the rate of the acceleration of the expansion. The authors consider reasons for the contradictions by theorizing a more and less dense galactic region. Learn more about the measurements and their implications online now here.
Synthetic Aperture Radar Used to Examine Mexico Earthquake
NASA released images taken with its Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) of the region of Mexico which suffered an earthquake in April. This is just another example of how SAR can help monitor the Earth from space, as discussed in an episode of A Green Space – A Green Earth with Bente Lilja Bye on Astrocast.TV. Learn more about the use of remote sensing imaging after the Mexico earthquake online now here.
ESA’s Venus Express Sheds More Light on Water Question
The European Space Agency (ESA) Venus Express is shedding more light on the question of the disappearance. For years now, scientists have theorized that Venus once had much more water, maybe even enough to have harbored the development of life. The latest results from the Venus Express have demonstrated that there is almost precisely twice as much hydrogen escaping the atmosphere of Venus as oxygen. This ratio is precisely what you would expect if the original source of both was water.
Learn more about the questions surrounding the water of Venus online now here.
Superstorm Discovered in the Atomosphere of an Exoplanet HD209458b
ESO Astronomers have measured a superstorm for the first time in the atmosphere of an exoplanet, the well-studied “hot Jupiter” HD209458b. The very high-precision
ESO Artists Impression
observations of carbon monoxide gas show that it is streaming at enormous speed from the extremely hot day side to the cooler night side of the planet. The observations also allow another exciting “first” — measuring the orbital speed of the exoplanet itself, providing a direct determination of its mass. Read more at http://www.eso.org/public/news/eso1026/