Posted on by Nancy Atkinson

Exoplanet Count Rises With New Discoveries

With several space- and ground-based telescopes, as well as dedicated space missions searching for exoplanets, or planets orbiting other stars, the count of new discoveries keeps rising. The current total now stands at 287 planets. The newest spacecraft dedicated to this search, the COROT Mission (Convection, Rotation and planetary Transits), announced the finding of two new exoplanets as well as an unknown celestial object. This discovery may be a “missing link” between stars and planets astronomers have been searching for.

The two new planets are gas giants of the hot Jupiter type, which orbit very close to their parent star and tend to have extensive atmospheres because heat from the nearby star gives them energy to expand. Most of the exoplanets found so far are the gas giant variety because of the limits of current technology.

In addition, an oddity dubbed “COROT-exo-3b” has raised particular interest among astronomers. It appears to be something between a brown dwarf, a sub-stellar object without nuclear fusion at its core but with some stellar characteristics, and a planet. Its radius is too small for it to be a super-planet.

If it is a star, it would be among the smallest ever detected. Follow-up observations from the ground have determined it to be at 20 Jupiter massses. This makes it twice as dense as the metal Platinum.

COROT has also detected extremely faint signals that, if confirmed, could indicate the existence of another exoplanet, as small as 1.7 times Earth’s radius.

This is an encouraging sign in the delicate and difficult search for small, rocky exoplanets that COROT has been designed for.

COROT launched in December 2006, with operations beginning in February of 2007. So far the mission has found four exoplanets. The mission started observations of its sixth star field at the beginning of May this year. During this observation phase, which will last 5 months, the spacecraft will simultaneously observe 12,000 stars.

More about COROT.

Original News Source: ESA

Posted on by Nicholos Wethington

Over 100 Explosions Observed on the Moon

In the past two and a half years, the Moon has taken a real beating. NASA astronomers have observed over a hundred explosions on the Moon during this time, caused by meteoroids both large and small, slamming into the Moon at speeds of up to 160,000 miles per hour (257,495 kilometers per hour).

The Moon gets pelted constantly – over a metric ton of material falls on the Moon every day! Most impacts are too dim to see with the naked eye because they are small micrometeorites. The rate of the flashes from larger impacts increases dramatically – up to an impact every hour – during meteor showers such as the Perseids and Quadrantids. The sporadic impacts account for twice as many observable events as compared to meteor shower impacts.

If you were standing on the Moon, you wouldn’t see these impacts as “shooting stars,” though, since there is no atmosphere in which they can burn up. The explosion is also not something like one would see here on Earth, as the absence of oxygen doesn’t allow for any combustion. The kinetic energy of the impact heats up the rocks on the surface to the point where they become molten, and glow for a short period after the impact.

Pictured left is the flash from a confirmed impact on March 13th, 2008, as captured by amateur astronomer George Varros. The small white point in the bottom right of the picture is where the impact occurred. He has an animation of the event on his site.

Monitoring the number of impacts on the Moon is important for future missions to visit our smaller neighbor, as well as for the eventual establishment of a Moon base. It will be important to know when astronauts should take cover from potential strikes during peak periods of impacts. After all, even a small meteoroid traveling between 4500 mph (7,242 kph) and 160,000 mph (257, 495) could do a lot of damage to a space suit or lunar base. A typical blast that can be seen with a backyard telescope from Earth is equivalent to a few hundred pounds of TNT. I know I wouldn’t want to go for a Moon walk during a meteor shower…

NASA has been observing lunar impacts with one 14-inch (36 cm) telescope and one 20-inch (51 cm) located at the Marshall Space Flight Center in Alabama, and one 14-inch telescope located in Georgia.

But it’s not just NASA that can see these lunar fireworks: NASA’s Meteoroid Environment Office has called for amateur astronomers to help in recording and confirming these flashes. If you have a lot of patience, a telescope and a way to record the flashes, check out their site to get started.

Source: Physorg, NASA

Posted on by Ian O'Neill

Solar Sonic Boom: Eclipses May Generate Atmospheric Shocks

The shadow of a lunar eclipse (NASA)

Something strange happens during a solar eclipse. As the Moon’s shadow passes over the surface of the Earth, observers have noticed mysterious bands of shadow ripple ahead and behind the eclipse. It seemed possible that these bands were a result of constructive and destructive interference of sunlight around the limb of the Moon (an effect known as diffraction), or atmospheric turbulence may have had a part to play. However, a new theory has come to light. As the Moon’s shadow travels across the Earth’s surface, it may be possible that the shadow cools the atmosphere suddenly, creating a pressure difference. This gives rise to a sonic phenomenon: a shock front. This may refract the path of light from the lunar limb and through the atmosphere, creating the bands of light and dark. The solar eclipse may be a sonic phenomenon as well as an optical one…

If an object travels faster than the speed of sound, a shock will form. This shock is generated as a body passes through the atmosphere faster than sound can propagate. On Earth, at sea level, the speed of sound is approximately 1,225 kilometres per hour (or 761 miles per hour; i.e. the sound of an explosion would take an hour to travel a distance of 761 miles). Should an aircraft travel at 1,225 km/hr or beyond, the pressure waves it generates cannot keep up with the plane. In this case, a shock wave will form, more commonly known as a “sonic boom” for stationary observers.

So, back to the solar eclipse. How can the shadow of the Moon create a sonic boom? It’s only a shadow, it’s not a solid body moving inside the atmosphere; surely a shock isn’t possible? Actually, research carried out by astrophysicist Dr Stuart Eves who works with the Surrey Satellite Technology Limited (SSTL) suggests it may be possible, and the phenomenon produced is known as “infrasound”. He believes that as the lunar shadow passes over the Earth’s surface, there is intense, local cooling of the atmosphere after the leading and before trailing edge of the eclipse. This cooling sets up a sudden pressure difference.

“As the eclipse shadow moves through the atmosphere, the sudden disappearance of the Sun changes the Earth’s temperature.” – Dr Eves.

If we consider that the eclipse shadow travels at supersonic velocities (1,100 miles per hour at the equator and up to 5,000 miles per hour near the poles), and the strong pressure gradient travels with the eclipse, a shock front is created in the atmosphere, generating infrasound waves. The sub-audible infrasound generated by this occurrence modifies the atmosphere to such an extent that it will deflect the path of light through the atmosphere. In this case, the light and dark bands around the eclipse shadow would be created by refraction.

Some scientists are sceptical about this new theory, but Eves thinks his explanation may also help to explain other phenomena during eclipses. Infrasound may be responsible for strange Foucault pendulum behaviour (the sensitive pendulums – used to demonstrate the rotation of the Earth – swing wildly during eclipses). The infrasound pulses may cause the ground to vibrate, interfering with the pendulum swing. Infrasound may also explain some bizarre animal behaviour during these events. Sub audible sound wave frequencies are known to distress or alarm birds, perhaps their strange behaviour during eclipses could be down to infrasound propagation.

Source: BBC

Posted on by Nancy Atkinson

Avoiding the Technicolor Yawn In Space

Astronauts don’t talk much about it, but about half of those who fly in space experience Space Adaptation Syndrome (SAS), or space sickness, which includes nausea, vertigo, visual illusions and headaches. Even though SAS isn’t life threatening, the onset of these symptoms at a crucial point in the mission could have potentially detrimental affects. The last thing any space flight needs is a violently ill commander or pilot during important maneuvers like docking to the space station, or a spacewalker doing the Technicolor Yawn in his helmet. Researchers have determined that SAS is not caused so much by the weightlessness experienced in space, but more by the body adapting to a different gravitational force. A Dutch PhD student studying SAS believes she may have developed a ground-based method for identifying people who are subject to space sickness, following her research in which she whirled test subjects around in a centrifuge.

Until now, no one could determine which astronauts would experience SAS. It can strike seasoned fighter-pilots-turned-astronauts who would claim to be immune from motion sickness, and additionally frequent flyer astronauts can experience SAS on one mission, but not another, while some rookie astronauts are symptom-free.

But Suzanne Nooij says her research shows that an astronaut who will suffer space sickness in microgravity conditions will also suffer it after being vigorously centrifuged at 3G for an hour or so. Spinning at that force is somewhat easily endured for that amount of time, but Nooij says, if you’re susceptible to SAS, once you get out of the centrifuge you’ll puke.

Nooij focused her research on the organ of balance, the area in the inner ear made of semi-circular canals, which are sensitive to rotation, and “otoliths,” saccules inside the ear which are sensitive to linear acceleration. Previous research suggests that a difference between the functioning of the left and right otolith contributes to susceptibility to sickness among astronauts. If this is the case, this should also apply after lengthy rotation.

Nooij tested this otolith asymmetry hypothesis. The otolith and semi-circular canals functions on both sides were measured of fifteen test subjects known to be susceptible to space sickness. Those who suffered from space sickness following rotation proved to have high otolith asymmetry and more sensitive otolith and canal systems. These people could not be classified as sensitive or non-sensitive on the basis of this asymmetry alone, but could on the basis of a combination of various otolith and canal features. This demonstrates that the entire organ of balance is involved in space sickness and that it probably entails complex interactions between the various parts of the organ of balance.

While researchers have yet to find a cure for this, previous knowledge of a space flyer’s susceptibility to SAS would allow for preventative measures such as taking motion sickness medicine, limiting food intake, and avoiding quick head movements.

While Nooij is not an astronaut, her PhD supervisor at TU Delft, is Wubbo Ockels, the first Dutchman in space in 1986, who suffered from SAS.

Original News Sources: Physorg, The Register

Posted on by Nancy Atkinson

More Satellite Images of China’s Earthquake

Beichuan Region of China, before and after Earthquake. Image credit: Formosat 2

More satellite images have been released portraying the devastation caused by the May 12, 2008 earthquake that struck China’s Sichaun Basin. This pair of images, captured by Taiwan’s Formosat-2, illustrates the challenges faced by rescuers bringing equipment and supplies to survivors of the massive 7.9-magnitude earthquake. The top “before” image from 2006 shows the tree-covered mountain terrain of China’s Beichuan County. A river curves along the base of the mountain, and a road follows the banks of the river.

In the lower image, taken on May 14, 2008, the landscape is almost unrecognizable. A landslide engulfed the entire mountainside, turning its green slopes brown. Both the road and the river are entirely gone, buried under the rubble, which rises in a mound up the opposite slope. Landslides, flooding and buckled roads have made travel within quake-affected regions difficult.


Landslides have created earthen dams, and new lakes were formed overnight. This pair of high-resolution images from Taiwan’s Formosat-2 satellite show a “before” and “after” comparison from May 14, 2006 (top),and May 14, 2008 (bottom.) Several landslides, a collapsed bridge, and a bridge submerged by a newly formed lake are visible in the “after” the earthquake image.


Finally, this bottom series of images show how devastation continues to occur as the earthquake and its aftershocks has sent earth and rock tumbling down mountains into rivers, creating natural dams behind which lakes quickly built up. The first, a “before” image taken in 2006, show normal springtime conditions.

On May 15, 2008, three days after the initial earthquake, both the bridge and the roads it connected had disappeared under murky water. Some sections of the villages remained above the waterline, as did portions of the roads leading to the villages. The tops of trees, perhaps on slightly higher ground, formed tiny islands near the shores of the growing lake.

Formosat-2 took the final image on May 19, 2008. By this time, water levels in the earthquake lake had risen enough to immerse both villages and the entire road network. Tan debris floats on the surface of the water, concentrated over the locations of the villages.

Earthquake-created dams present a dual danger. Apart from the upstream floods that occur as a lake builds behind the natural dam, the piles of rubble that form the dam may be unstable. Another quake or simply the pressure of water behind it could burst the dam, sending a wall of water downstream. Downstream floods may also occur when water begins to cascade over the top of the dam. Thousands of people were evacuated from Beichuan on May 17 when one such lake threatened to burst, said China Daily.

Original News Source: NASA’s Earth Observatory

Posted on by Fraser Cain

The Difference Between Reflectors and Refractors

When you choose a telescope, there are two main kinds you can pick from, reflectors and refractors. Both can be wonderful for viewing the night sky. They use basically different methods to boost light from dim objects in the sky. Here’s how they work, and how they’re different.

Refractor Telescopes
Here’s what’s inside a basic refractor telescope. The job of the objective lens, opposite the eyepiece end, is to gather the light coming from a distant object, such as a star, and bend it into a single point of focus. A second lens’ (the eyepiece) job is to enlarge that focused image for our retina; it acts as a magnifying glass. Think of the focused light coming in from the first lens as a bug, and think of the eyepiece magnifier as a basic magnifying glass that we look at the bug with. That’s it in a nutshell.


Reflector Telescopes
A reflector telescope uses two mirrors instead of two lenses. Isaac Newton developed this telescope to combat chromatic aberration (a rainbow seen around some objects viewed with a refractor telescope). A mirror used to gather light doesn’t suffer from this effect. Light from an object enters the telescope tube and is reflected off a curved mirror at the end of the tube. A second, small, flat mirror in the middle of the tube reflects this image to the eyepiece. There are potential problems associated with the mirrors. Firstly, some light is always lost in the reflection; good quality telescopes can usually gather 90% of the light coming in. Secondly, the mirror might not be a perfect curve, so the image being reflected will not come to a perfect point. This results in a dragging effect; a point could be seen as a line or cross. Also, the mirrors need to be cleaned and realigned from time to time.
Posted on by Nancy Atkinson

Congress Considering Additional Shuttle Flight and More Science Funding

A bill directing NASA to fly an additional space shuttle mission to deliver the $1 billion Alpha Magnetic Spectrometer to the International Space Station cleared the House Science and Technology space and aeronautics subcommittee. The NASA Authorization Act of 2008 (H.R. 6063) was quickly approved sent on to the full committee for consideration. The bill also authorizes a $19.2 billion budget for NASA for 2009, or about $1.6 billion more than the White House is requesting. Additionally, it would authorize an additional $1 billion in 2009 to accelerate development of the Orion Crew Exploration Vehicle and Ares I launcher. Rep. Mark Udall (D-Colo.), the subcommittee’s chairman, introduced the legislation five days ago, stating concerns about the five-year gap between when the shuttle is retired to when the Orion vehicle will be ready to transport crew and supplies to the ISS.

The legislation would still put NASA on pace to return to the Moon around 2020. But it also would provide more funds for climate monitoring satellites, such as a new Landsat satellite, and Glory, which would gather data on aerosols and black carbon in Earth’s atmosphere. The additional shuttle flight to bring the spectrometer science payload to the ISS would ease concerns of the international partners and reverse a controversial cut to the ISS’s science capabilities.

If you are a US citizen and agree with these appropriations, consider contacting your congressmen to encourage their support of this bill.

Text of full bill.

Original News Source: Yahoo News

Posted on by Fraser Cain

What are Telescopes?

This artist’s rendering shows the Extremely Large Telescope in operation on Cerro Armazones in northern Chile. The telescope is shown using lasers to create artificial stars high in the atmosphere. Image: ESO/E-ELT
This artist’s rendering shows the Extremely Large Telescope in operation on Cerro Armazones in northern Chile. The telescope is shown using lasers to create artificial stars high in the atmosphere. Image: ESO/E-ELT

Early theories of the Universe were limited by the lack of telescopes. Many of modern astronomy’s findings would never have been made if it weren’t for Galileo Galilei’s discovery. Pirates and sea captains carried some of the first telescopes: they were simple spyglasses that only magnified your vision about four times and had a very narrow field of view. Today’s telescopes are huge arrays that can view entire quadrants of space. Galileo could never have imagined what he had set into motion.

Here are a few facts about telescopes and below that is a set of links to a plethora of information about them here on Universe Today.

Galileo’s first telescopes were simple arrangements of glass lenses that only magnified to a power of eight, but in less than two years he had improved his invention to 30 power telescope that allowed him to view Jupiter. His discovery is the basis for the modern refractor telescope.

There are two basic types of optical telescopes; reflector and refractor. Both magnify distant light, but in different ways. There is a link below that describes exactly how they differ.

Modern astronomer’s have a wide array of telescopes to make use of. There are optical observation decks all around the world. In addition to those there are radio telescopes, space telescopes, and on and on. Each has a specific purpose within astronomy. Everything you need to know about telescopes is contained in the links below, including how to build your own simple telescope.

Posted on by Nancy Atkinson

Caught in the Act: Astronomers See Supernova As it Explodes

First supernova caught in the act (Alicia Soderberg, Princeton University)

The Swift satellite has made another fortuitous observation. This time, and for the first time ever, astronomers have caught a star in the act of going supernova. These stellar explosions have been observed before, but always after the fireworks were well underway. “For years we have dreamed of seeing a star just as it was exploding, but actually finding one is a once-in-a-lifetime event,” says Alicia Soderberg, from Princeton University, who is leading the international group studying this explosion. “This newly born supernova is going to be the Rosetta Stone of supernova studies for years to come.”

In January of 2008 Soderberg was expecting to study a month-old supernova that was already underway. But as she and her assistant studied the X-ray emissions conveyed from space by NASA’s Swift satellite, they saw an extremely bright light that seemed to jump out of the sky. They didn’t know it at the time, but they had just become the first astronomers to have caught a star in the act of exploding.

“In the old days — last year — people found supernovae by their optical light and then started to study them to understand which stars blow up, what the mechanism is and what they produce,” said Robert Kirshner, a professor of astronomy at Harvard University. “But this is something new — the X-rays come right at the beginning and provide a very early alert to the event.”

Soderberg regards the discovery as a case of extreme serendipity. The satellite was pointing in the right place at the right time, she said, because she had asked Neil Gehrels, Swift’s lead scientist at NASA’s Goddard Space Flight Center to turn it that way to look at another supernova. And while she was away lecturing, she had asked her colleague, Edo Berger, to keep an eye on the data for her.

“It’s a really lucky chain of events — a surprise,” said Soderberg, who is leading the group studying the explosion. “It was all over in a matter of minutes.”

Other observatories also turned their telescopes toward this stellar explosion, making detailed observations of the event, including the Hubble Space Telescope, the Chandra X-ray Observatory, Palomar’s 60- and 200-nch telescopes, the Gemini Observatory and Kitt 1 Telescope in Hawaii, and the Very Large Array and Apache Point Observatories in New Mexico. This will allow a very detailed study of this event.

A typical supernova occurs when the core of a massive star runs out of nuclear fuel and collapses under its own gravity to form an ultradense object known as a neutron star. The newborn neutron star compresses and then rebounds, triggering a shock wave that plows through the star’s gaseous outer layers and blows the star to smithereens. Until now, astronomers have only been able to observe supernovae brightening days or weeks after the event, when the expanding shell of debris is energized by the decay of radioactive elements forged in the explosion.

Original News Source: Princeton University Press release

Posted on by Nancy Atkinson

Test Your Knowledge With Another “Where In The Universe” Challenge

It’s Wednesday, so that means its time for another “Where In The Universe” challenge to test your visual knowledge of the cosmos. We’ve been busy searching hither and yon for unusual and unique astronomical images to see how well our readers are acquainted with the various locals across the universe. This week’s image is an unusual looking object. Just what is this thing? Could it be an asteroid, a wierd moon, or something you can find on Earth? Hmmm…… Ponder the image for awhile, and no peeking below before you make a guess. If only I could insert some music here, like the “Think!” theme song from the Jeopardy game show. I’ll have to talk to Fraser about that…

Have you made your guess?

And are you sure?

This is a Cassini image of Saturn’s unusual moon Hyperion. Hyperion is the largest highly irregular (non-spherical) body in the solar system. Scientists believe its very likely that is a fragment of a larger body that was broken by a large impact in the distant past. Is this a coral reef in space?

This sponge-like looking moon is a remarkable world strewn with strange craters and basically a strange surface. At the bottom of most craters lies some type of unknown dark material. Astronomers think the dark material might be only tens of meters thick in some places. Hyperion is about 250 kilometers across, rotates chaotically, and has a density so low that it might be mostly hollow inside — it may house a vast system of caverns. Wouldn’t that be fun to explore!

Or its low density could indicate that it is composed of water ice with only a small amount of rock and considerably porous. It’s very low density also seems to allow impacts to form deeper and sharper craters.

But unlike most of Saturn’s moons, Hyperion has a low albedo (.2 – .3) indicating that it is covered by at least a thin layer of dark material. Cassini data from 2007 indicates that this material is rich in organic molecules. Quite an interesting place, this Hyperion.

How did you do on this week’s challenge?

Original Source: APOD, Nine Planets