Astrocast.TV

Frugal Aliens Might Be Sending in a Cost-Effective Way

The Search for Extra-terrestrial Intelligence (SETI) has been the focus of a dedicated group of scientists for the past 50 years.  The process, developed in the 1960s, involves listening for signals from nearby stars and trying to decipher any type of intentional message from among the noise of space. And, make no mistake about it, space is noisy.

No signals have been found yet, and that has some researchers wondering if there isn’t a better and more cost-effective way to monitor signals.  But, has anybody thought about what sending messages across space might cost a civilization?  Gregory Benford, an astrophysicist at University of California-Irvine is. He’s teamed up with his twin brother James, who is a physicist specializing in microwave technology, to look at the problem from the point of view of the folks on other worlds who we have been hoping were sending messages to us.  Their conclusions, publihsed in the June of the journal Astrobiology, assume that any alien civilization might want to save money and resources and send their messages in the most cost-effective way possible. This means optimizing the use of bandwidth and sending narrowly focused beams that carry pulsed signals in the 1- to 10-gigahertz range.

James Benford likens that approach to being more like Twitter, with its shortened, efficient methodology of sending messages.  James and Gregory (who is also a science fiction writer) have caught the attention of the SETI community with their so-called “Benford Beacons”.  Researchers are taking a look at their current efforts, which focus their receivers on narrow-band input. They’ve come to the conclusion that they may be looking for the wrong kind of signals. The Benfords and a growing number of scientists involved in the hunt for extraterrestrial life advocate adjusting SETI receivers to maximize their ability to detect direct, broadband beacon blasts.

Once that’s done, the next question will focus on where to look for these little beacons. The Benfords suggest star-rich areas of the Milky Way, particularly toward the center where stars are at least a billion years older than the Sun. Those stars might stand a good chance of harboring life of the intelligent variety.

To hear more about these Benford Beacons, watch this video interview with James Benford.

If you’re interested in learning more about all the aspects of SETI, consider attending SETICon, being held August 13-15, 2010. Details at are SETIcon.com.

No… Maybe It’s A Cometary Planet

Astronomers used the Hubble Space Telescope’s Cosmic Origins Spectrograph (COS) to study the ultraviolet-light fingerprints of elements in light streaming away from a star located 153 light-years from Earth. What’s so important in that starlight?  According to astronomer Jeffrey Linsky of the University of Colorado, Boulder, the evidence from the spectrograph shows that there’s a “baked” object orbiting the star.

The chemical elements in the starlight are actually evidence that the planetary atmosphere is being heated by the nearby star and escaping into space. The fleeing atmospheric gases are being swept into a tail, giving the planet — named HD 209458b — a comet-like appearance.

“Since 2003 scientists have theorized the lost mass is being pushed back into a tail, and they have even calculated what it looks like,” said Linsky, who is the leader of the COS study. “We think we have the best observational evidence to support that theory. We have measured gas coming off the planet at specific speeds, some coming toward Earth. The most likely interpretation is that we have measured the velocity of material in a tail.”

The planet is not Earth-like, but instead is more Jupiter-like. It orbits 100 times closer to its star than Jupiter does to the Sun. That gives this roasted planet a very short year — only 3.5 days long.  For this reason, plus its proximity to Earth and the fact that it is one of the few known exoplanets that can be seen passing in front of (transiting) its star, HD 209458b is one of the most intensely scrutinized alien worlds in our part of the galaxy.  The fact that this star transits its star so frequently allowed Linsky and his team to use COS to analyze the planet’s atmosphere as it passed in front of the star.

During a transit, astronomers study the structure and chemical makeup of a planet’s atmosphere by sampling the starlight that passes through it. The dip in starlight because of the planet’s passage, excluding the atmosphere, is very small, only about 1.5 percent. When the atmosphere is added, the dip jumps to 8 percent, indicating a bloated atmosphere.

COS detected the heavy elements carbon and silicon in the planet’s super-hot 2,000 degrees Fahrenheit atmosphere. This detection revealed the parent star is heating the entire atmosphere, dredging up the heavier elements and allowing them to escape the planet.

The COS detection isn’t the first time a Hubble Space Telescope instrument has detected this cometary planet’s atmosphere. The Space Telescope Imaging Spectrograph (STIS) first observed the planet in 2003 and found the first evidence of this world’s evaporating atmosphere.  COS’s followup study gave astronomers much  more detail and is allowing them to study the action in ultraviolet wavelengths.

JAXA announce the Small Solar Power Sail Demonstrator “IKAROS” has reached a successful acceleration of  a  photon (*1)  after its sail deployment. IKAROS was launched by JAXA on May 21, 2010 (JST) .  The thrust by solar light pressure is 1.12 mili-Newton (*2,) which is the expected value.  JAXA has announced, “the IKAROS was proved to generate the biggest acceleration through photon during interplanetary flight in history.”

Read more in the JAXA Press Release.

Rosetta’s Encounter with An Asteroid

A series of closest-approach images of 21 Lutetia, returned by the ESA's Rosetta spacecraft. Courtesy European Space Agency, Rosetta Mission. Click to enlarge.

The Rosetta spacecraft, a project of the European Space Agency, has just completed a close fly-by of the mysterious asteroid 21 Lutetia. The spacecraft flew within 3,160 kilometers and took a series of images that reveal a lumpy, battered surface that seems to have a thick layer of regolith (the technical term for a layer of loose “soil” on the rocky surfaces of places like Mars, the Moon — and apparently, 21 Lutetia).  Planetary scientists will be studying images and spectra of Lutetia to determine just what it’s surface composition is — and, given its beat-up appearance — the impact cratering and formation history of this asteroid.

Why study asteroids up close?  These little chunks of rock are more than simply space debris. They give us insight into the earliest epochs of solar system formation — and the birth of planets like Earth and Mars. Asteroids contain some of the oldest materials in the solar system. The rocky bodies of the larger planets formed from rocks like these during the early evolution of the solar system. They condensed out of the disk of material left over from the birth of the Sun. As time went by, the chunks of rock, sometimes called planetesimals, collided to form ever-larger worlds.

Thus, the evolutionary history of our solar system is written in the minerals of these asteroids. And, places like 21 Lutetia continue to experience impacts in the modern era — giving solar system researchers insight into the complex dynamical evolution of the asteroids today.

You can follow the Rosetta mission and see the latest images at the ESA’s Rosetta Blog.  It features first-look images taken during the flyby. Scientist interviews are available on ESA’s Livestream channel.  Watch and learn what planetary astronomers are finding out about Lutetia from Rosetta’s images and data.

While much of the lights in the evening will be fireworks throughout the USA in celebration of Independence Day, take this opportunity to observe some celestial lights in the night sky. About one and a half hours after sunset, look in the west for Venus. It will only be about 6 degrees away from Regulus, the brightest star in Leo the Lion. Also note that Venus, Mars and Saturn this evening will span a mere 35 degrees of the sky, roughly in a line with that which is known as the ecliptic, the apparent path of the Sun in the sky. Take a look with a pair of binoculars (often used to see fireworks) and you will catch this planetary alignment. Download a free sky map online here to see what else you might find in the night sky, other than fireworks.

NASA’s Transition Region And Coronal Explorer (TRACE) satellite, launched back on 1 April 1998 was officially retired by NASA as of this past Tuesday. TRACE has been allowing scientists to study the Sun, especially its corona. The work of TRACE will now be “carried out by NASA’s newest eye on the sun, the Solar Dynamics Observatory (SDO), a Goddard-built spacecraft managed by the Science Mission Directorate’s Heliophysics Division.” Learn more about the changing of the guard in solar studies online now here.

Back in April, the European Space Agency (ESA) launched a satellite named CryoSat-2 for the purpose of measuring ice thickness in the Arctic region. Although the satellite is still undergoing checkout and calibration, the first results from CryoSat-2 were released to the participants at the Living Planet Symposium. The symposium is being held in Bergen, Norway this year, from 28 June to 2 July 2010 and organized with the support of the Norwegian Space Centre. Learn more about sea ice thickness and the latest data released by ESA from CryoSat-2 online now here.

NASA’s Tropical Rainfall Measuring Mission satellite (TRMM) has been monitoring the hurricane in the Gulf of Mexico now called Alex. The TRMM satellite was specifically designed to measure precipitation in the tropics region of Earth. It has been in orbit since its launch on 27 November 1997.
Check out the images of hurricane Alex from NASA’s TRMM satellite online now here and here.

 
The “big” event of the month of July 2010 is actually a daytime event, namely a total solar eclipse. Unfortunately, the path of totality of this total solar eclipse is over the south Pacific Ocean. One island in the path of totality is Easter Island. This is the island most well known for its unique statues. No one really knows how and why these stone monuments were built. If you have clear skies and are able to stay up all night, you should be able to catch all 5 of the naked eye planets (Mercury, Venus, Mars, Jupiter and Saturn). Learn more about what is up in the sky in the evening this month of July online now in the latest “Our Night Sky” segment of Astrocast.TV.

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.