Posted on by Nancy Atkinson

Searching for Life As We Don’t Know It

Artist's impression of exoplanets around other stars. Credits: ESA/AOES Medialab

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When discussing the possibility of finding life on other worlds, we usually add the phrase “life – as we know it.” But we’ve been surprised at exotic forms of life even on our own world and we need figure out how life might evolve elsewhere with foreign biochemistry in alien environments. Scientists at a new interdisciplinary research institute in Austria are working to understand exotic life and how we might find it.

Traditionally, planets that might sustain life are looked for in the ‘habitable zone’, the region around a star in which Earth-like planets with carbon dioxide, water vapor and nitrogen atmospheres could maintain liquid water on their surfaces. Consequently, scientists have been looking for biomarkers produced by extraterrestrial life with metabolisms resembling the terrestrial ones, where water is used as a solvent and the building blocks of life, amino acids, are based on carbon and oxygen. However, these may not be the only conditions under which life could evolve.

The University of Vienna established a research group for Alternative Solvents as a Basis for Life Supporting Zones in (Exo-)Planetary Systems in May 2009, under the leadership of Maria Firneis.

“It is time to make a radical change in our present geocentric mindset for life as we know it on Earth,” said Dr. Johannes Leitner, from the research group. “Even though this is the only kind of life we know, it cannot be ruled out that life forms have evolved somewhere that neither rely on water nor on a carbon and oxygen based metabolism.”

One requirement for a life-supporting solvent is that it remains liquid over a large temperature range. Water is liquid between 0°C and 100°C, but other solvents exist which are liquid over more than 200 °C. Such a solvent would allow an ocean on a planet closer to the central star. The reverse scenario is also possible. A liquid ocean of ammonia could exist much further from a star. Furthermore, sulphuric acid can be found within the cloud layers of Venus and we now know that lakes of methane/ethane cover parts of the surface of the Saturnian satellite Titan.

Consequently, the discussion on potential life and the best strategies for its detection is ongoing and not only limited to exoplanets and habitable zones. The newly established research group at the University of Vienna, together with international collaborators, will investigate the properties of a range of solvents other than water, including their abundance in space, thermal and biochemical characteristics as well as their ability to support the origin and evolution of life supporting metabolisms.

“Even though most exoplanets we have discovered so far around stars are probably gas planets, it is a matter of time until smaller, Earth-size exoplanets are discovered,” said Leitner.

The research group discussed their initial investigations at the European Planetary Science Conference in Potsdam, Germany.

Source: Europlanet

Posted on by Nancy Atkinson

Space Shuttle Flushes the Toilet for All the World To See

Shuttle with water dump. Copyright Clair Perry

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This picture is from last week; September 9, 2009 to be exact, but I still wanted to share it. I just got in touch with photographer Clair Perry from Prince Edward Island, Canada to get his permission to post the image. No, this is not a comet. Pictured is space shuttle Discovery executing a water dump. The shuttle needed to get rid of excess waste water before landing the next day, and jettisoned it overboard via the waste water dump line, creating a spectacular visual effect as sunlight hit the spraying water. This dump occurred just as the shuttle was flying over North America last week, and lots of people witnessed this “toilet flush.” Some reports indicated it was “pristine” water (the shuttle fuel cells’ by-product is water) and other reports said it was “waste water and urine” (the Bad Astronomer called it Constellation Urion). Whatever, it was pretty. NASA said this was an unusually large dump, about 150 pounds (68 kg), because new regulations say no shuttle water dumps can take place while docked to the ISS, so as not to contaminate the outdoor experiments on the Kibo lab.

See below for the spectacular entire image, which also includes the nearby ISS creating a streak in the sky. Thanks to Clair Perry for sharing his images.

Shuttle and ISS on 9/9/09. Copyright Clair-Perry
Shuttle and ISS on 9/9/09. Copyright Clair-Perry

And if you’re worried about the water ice freezing and becoming projectiles in orbit, NASA says that while waste water usually freezes upon jettison into a cloud of tiny ice droplets, when the sun hits, the ice sublimates directly into water vapor and disperses in space.

I remember the first time I saw a shuttle water dump. It was back in 2000, and I had gotten up early, about 4:45 am, to watch the shuttle pass over. But I saw this strange sight, like something was coming off of the shuttle. I ran inside and turned on NASA TV, just in time to see a view of a golden spray shooting out of the shuttle — the sunlight hitting the water at just the right angle made it look like a shimmering gold spray. Gold, not yellow.

Posted on by Fraser Cain

God Particle

The Large Hadron Collider at CERN. Credit: CERN/LHC

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When the media talks about the “god particle”, they’re really talking about a theoretical particle in physics known as the higgs boson. If reality matches the predictions made by theoretical physics, the higgs boson is the particle that gives objects mass. It explains why objects at rest tend to stay at rest and objects in motion tend to stay in motion.

One of the primary goals of the Large Hadron Collider in Switzerland is to search for the so called “god particle”. When it finally gets running, the Large Hadron Collider, or LHC, will run beams of protons around a 27 kilometer circle, slamming them together at close to the speed of light. All the kinetic energy of the protons is instantly frozen out as mass in a shower of particles. Remember Einstein’s famous E=mc2 formula? Well, you can reconfigure the equation to be m = E/c2.

The higgs boson is thought to be a very heavy particle, and so it takes a lot of energy in the collider to create particles this massive. When the LHC starts running, it will collide protons at higher and higher energies, searching for the higgs boson. If it is found, it will confirm a theorized class of particles predicted by the theory of supersymmetry. And even if the higgs boson isn’t found, it will help disprove the theory. Either way, physicists win.

The term “god particle” was coined by physicist Leon Lederman, the 1988 Nobel prize winner in physics and the director of Fermilab. He even wrote a book called the “God Particle”, where he defended the use of the term.

We have written many articles about the Higgs Boson and the Large Hadron Collider here on Universe Today. Here’s an article about how the LHC won’t create a black hole and destroy the Earth. And here’s more on Fermilab’s search for the Higgs Boson.

We have also recorded an episode of Astronomy Cast all about the higgs boson. Listen to it here, Episode 69: The Large Hadron Collider and the Search for the Higgs Boson.

Posted on by Jean Tate

What is Cherenkov Radiation?

How the CANGAROO Imaging Cherenkov Air Telescope works

Cherenkov radiation is named after the Russian physicist who first worked it out in detail, in 1934, Pavel Alekseyevich Cherenkov (he got a Nobel for his work, in 1958; because he’s Russian, it’s also sometimes called Cerenkov radiation).

Nothing’s faster than c, the speed of light … in a vacuum. In the air or water (or glass), the speed of light is slower than c. So what happens when something like a cosmic ray proton – which is moving way faster than the speed of light in air or water – hits the Earth’s atmosphere? It emits a cone of light, like the sonic boom of a supersonic plane; that light is Cherenkov radiation.

The Cherenkov radiation spectrum is continuous, and its intensity increases with frequency (up to a cutoff); that’s what gives it the eerie blue color you see in pictures of ‘swimming pool’ reactors.

Perhaps the best known astronomical use of Cherenkov radiation is in ICATs such CANGAROO (you guessed it, it’s in Australia!), H.E.S.S. (astronomers love this sort of thing, that’s a ‘tribute’ to Victor Hess, pioneer of cosmic rays studies), and VERITAS (see if you can explain the pun in that!). As a high energy gamma ray, above a few GeV, enters the atmosphere, it creates electron-positron pairs, which initiate an air shower. The shower creates a burst of Cherenkov radiation lasting a few nanoseconds, which the ICAT detects. Because Cherenkov radiation is well-understood, the bursts caused by gamma rays can be distinguished from those caused by protons; and by using several telescopes, the source ‘on the sky’ can be pinned down much better (that’s what one of the Ss in H.E.S.S. stands for, stereoscopic).

The more energetic a cosmic ray particle, the bigger the air shower it creates … so to study really energetic cosmic rays – those with energies above 10^18 ev (which is 100 million times as energetic as what the LHC will produce), which are called UHECRs (see if you can guess) – you need cosmic ray detectors spread over a huge area. That’s just what the Pierre Auger Cosmic Ray Observatory is; and its workhorse detectors are tanks of water with photomultiplier tubes in the dark (to detect the Cherenkov radiation of air shower particles).

However I think the coolest use of Cherenkov radiation in astronomy is IceCube, which detects the Cherenkov radiation produced by muons in Antarctic ice … traveling upward. These muons are produced by rare interactions of muon neutrinos with hydrogen or oxygen nuclei (in the ice), after they have traveled through the whole Earth, from the Artic (and before that perhaps a few hundred megaparsecs from some distant blazer).

ICAT: imaging Cherenkov Air Telescope
CANGAROO: Collaboration of Australia and Nippon (Japan) for a Gamma Ray Observatory in the Outback
H.E.S.S.: High Energy Stereoscopic System
VERITAS: Very Energetic Imaging Telescope Array System
UHECR: ultra-high-energy cosmic ray

This NASA webpage gives more details of how ICATs work.

Quite a few Universe Today stories are about Cherenkov radiation; for example Astronomers Observe Bizarre Blazar with Battery of Telescopes, and High Energy Gamma Rays Go Slower Than the Speed of Light?.

Examples of Astronomy Casts which include this topic: Cosmic Rays, and Gamma Ray Astronomy.

Sources:
http://en.wikipedia.org/wiki/Cherenkov_radiation
http://abyss.uoregon.edu/~js/glossary/cerenkov_radiation.html

Posted on by Tammy Plotner

Weekend SkyWatcher’s Forecast – September 18-20, 2009

Greetings, fellow SkyWatchers! It’s an awesome weekend forecast for many of us attending Fall Star Parties, and all over the world we’re looking forward to moonless nights and the fellowship with our brother and sister amateur astronomers. If you’ve never been to a star party, try the Goggle pages for information… you just might find one going on near you! In the meantime, let’s have us a “Snowball” fight, chase some galaxies and ponder double stars! I’ll see you in the night…

Friday, September 18, 2009 – One of the most interesting features of the autumn sky is how slowly the stars and constellations seem to proceed across the heavens. This is only an illusion, since skydark arrives earlier each night (after summer solstice in the Northern Hemisphere), making the progress of the constellations across the sky seems to ‘‘freeze.’’ Tonight, Capella can be seen rising to the northeast just as Antares settles southwest. Four planets—Jupiter, Pluto, Neptune, and Uranus—are still above the horizon, with Jupiter now very low to the west-southwest. Descending to the northwest is Ursa Major, the ‘‘Big Dipper.’’ Across the sky is Piscis Austrinus, and lonely but bright Fomalhaut is beginning its rise. Seven stars of the first magnitude now grace the heavens. Against this backdrop, one of the darkest skies of the month is now upon us. It’s the New Moon…

Let’s have a look at another fine planetary nebula—NGC 7662. At 9 magnitude, this one is more commonly known as the ‘‘Blue Snowball’’ and can be found about three finger-widths east of Omicron Andromedae, or a little less than a handspan northwest of Alpha Pegasi (RA 23 25 54 Dec +42 32 06).

snowball

Similar in size to M57, even low power with a small scope easily reveals the planetary nature of this very fine study. Power up and you’ll discover that the annulus of this roughly circular planetary is definitely brighter inside than out. Large telescopes will highlight NGC 7662’s blue coloration and reveal a bright inner globe surrounded by a faint outer ring.

Saturday, September 19, 2009 – On this date in 1848, William Boyd was observing Saturn and discovered the planet’s eighth moon, Hyperion. If you’re out before sunset, some lucky stargazers are going to discover that the slender crescent Moon is about to occult Mercury! Check the Resources in this book and IOTA for locations and dates. Then check them both out in binoculars!

Would you like to try for another pair? Then wait until the skies are fully dark and head north for a galaxy and cluster pairing—NGC 6946 (RA 20 34 51 Dec +60 09 18) and NGC 6939 (RA 20 31 30
Dec +60 39 42).

6946

Located in western Cepheus, you’ll find them about a finger-width southwest of Eta.

6939Discovered by William Herschel on September 9, 1798, 10 million-light-year-distant face-on spiral NGC 6946 spreads itself pretty thin in modest instruments. Lacking a bright core, this oval mist orients southwest to northeast. Larger telescopes will reveal traces of rotating spiral arms, especially in the southwest. This galaxy would appear extraordinary if we weren’t looking through Milky Way obscuration to view it! Through smaller scopes, northwestern open cluster NGC 6939 appears like a tight little formation of 11th and 12th magnitude stars similar in pattern to a very small M11. It resolves well in larger scopes.

humboldtSunday, September 20, 2009 – Today we recognize the passing of cosmonaut Gherman S. Titov in 2000; Titov was not only the second human in space but also the youngest! Perhaps when he was orbiting Earth in Vostok 2 he had a chance to see the Moon. Why don’t we join him? Tonight, your lunar mission is to journey to the edge of the east limb and slightly south of central to identify crater Humboldt. Seen on the curve, this roughly 200-kilometer-wide crater holds a wealth of geographical details. Its flat, cracked floor has central peaks and a small mountain range, as well as a radial Rille structure. If libration and steadiness of skies are in your favor, power up and look for dark pyroclastic areas and a concentric inner crater.

betalyraeNow, let’s have a look at Beta and Gamma Lyrae, the lower two stars in the ‘‘Harp.’’ Beta is actually a quick-changing variable, which drops to less than half the brightness of Gamma in about 12 days. For a few days, the pair will seem of almost equal brightness, and then you will notice the star closest to Vega fade away. Beta is one of the most unusual spectroscopic stars in the sky, and it is possible that its eclipsing binary companion may be the prototype of a ‘‘collapsar’’ (yep, a black hole!), rather than a true luminous body.

Enjoy your weekend!!

This week’s awesome images (in order of appearance) are: NGC 7662 (credit—Adam Block/NOAO/AURA/NSF), NGC 6946 and NGC 6939 (credit—Palomar Observatory, courtesy of Caltech), Crater Humboldt (credit—Ricardo Borba) and Beta Lyrae (credit—Palomar Observatory, courtesy of Caltech). We thank you so much!!

Posted on by Tammy Plotner

IYA (Almost) Live Telescope!

Greetings! In case you weren’t tuned into Galactic TV yesterday… We had us a regular skyfest! Truly pristine dark skies ruled and the IYA “Live” telescope rocked the Aussie night away. For more than 8 hours we went from target to target – and loved every minute of it. While we could have done a lot more than four objects, allowing you time to enjoy them is a worthwhile effort, too. While I’d ordinarily spread this over a couple of days I’m going to post all our objects – M2, M41, M93 and M46 – right now because I’m outta’ here for the Hidden Hollow Star Party. Want to party at your end? Then check out information on our iPhone Galactic TV Weekend Marathon! Enjoy!!

Messier 2 or M2 (also designated NGC 7089) is a globular cluster in the constellation Aquarius, five degrees north of the star Beta Aquarii. It was discovered by Jean-Dominique Maraldi in 1746 and is one of the largest known globular clusters.

M2 was discovered by the French astronomer Jean-Dominique Maraldi in 1746 while observing a comet with Jacques Cassini. Charles Messier rediscovered it in 1760 but thought it a nebula without any stars associated with it. William Herschel was the first to resolve individual stars in the cluster, in 1794. M2 is, under extremely good conditions, just visible to the naked eye. Binoculars or small telescopes will identify this cluster as non-stellar while larger telescopes will resolve individual stars, of which the brightest are of apparent magnitude 13.1.

M2 is about 37,500 light-years away from Earth. At 175 light-years in diameter, it is one of the larger globular clusters known. The cluster is rich, compact, and significantly elliptical. It is 13 billion years old and one of the older globulars associated with the Milky Way Galaxy. M2 contains about 150,000 stars, including 21 known variable stars. Its brightest stars are red and yellow giants. The overall spectral type is F4.

Messier 41 (also known as M41 or NGC 2287) is an open cluster in the Canis Major constellation. It was discovered by Giovanni Batista Hodierna before 1654 and was perhaps known to Aristotle about 325 BC.

M41 lies about four degrees almost exactly south of Sirius. It contains about 100 stars including several red giants, the brightest being a spectral type K3 giant near the cluster’s center. The cluster is estimated to be moving away from us at 23.3 km/s. The diameter of the cluster is between 25 and 26 light years. Its age is estimated at between 190 and 240 million years old. M41 is also referred to as NGC 2287.

Messier 93 (also known as M 93 or NGC 2447) is an open cluster in the constellation Puppis. It was discovered by Charles Messier in 1781.

M93 is at a distance of about 3,600 light years from Earth and has a spatial radius of some 10 to 12 light years. Its age is estimated at some 100 million years.

Messier 46 (also known as M 46 or NGC 2437) is an open cluster in the constellation of Puppis. It was discovered by Charles Messier in 1771. Dreyer described it as “very bright, very rich, very large.” M46 is about 5,500 light-years away with an estimated age on the order of several 100 million years.

The planetary nebula NGC 2438 appears to lie within the cluster near its northern edge, but it is most likely unrelated since it does not share the cluster’s radial velocity. The case is yet another example of a superposed pair, joining the famed case of NGC 2818.

M46 is about a degree east of M47 in the sky, so the two fit well in a binocular or wide-angle telescope field.

If you had fun with this, then make sure to tune into your TVU Channel Number 79924 on your iPhone for a weekend marathon of all the best of our IYA Live Telescope! Wishing you all clear skies and a great weekend….

Factual information courtesy of Wikipedia.

Posted on by Nancy Atkinson

Planck First Light

Strips of the sky measured by Planck. Credit: ESA

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One of the newest telescopes in space, the Planck spacecraft, recently completed its “first light” survey which began on August 13. Astronomers say the initial data, gathered from Planck’s vantage point at the L2 point in space, is excellent. Planck is studying the Cosmic Microwave Background, looking for variations in temperature that are about a million times smaller than one degree. This is comparable to measuring from Earth the body heat of a rabbit sitting on the Moon.

The initial survey yielded maps of a strip of the sky, one for each of Planck’s nine frequencies. Each map is a ring, about 15° wide, stretching across the full sky.

The the differences in color in the strips indicate the magnitude of the deviations of the temperature of the Cosmic Microwave Background from its average value, as measured by Planck at a frequency close to the peak of the CMB spectrum (red is hotter and blue is colder).

The large red strips trace radio emission from the Milky Way, whereas the small bright spots high above the galactic plane correspond to emission from the Cosmic Microwave Background itself.

In order to do its work, Planck’s detectors must be cooled to extremely low temperatures, some of them being very close to absolute zero (–273.15°C, or zero Kelvin, 0K).

Routine operations are now underway, and surveying will continue for at least 15 months without a break. In approximately 6 months, the first all-sky map will be assembled.

Within its projected operational life of 15 months, Planck will gather data for two complete sky maps. To fully exploit the high sensitivity of Planck, the data will require delicate adjustments and careful analysis. It promises to return a treasure trove that will keep both cosmologists and astrophysicists busy for decades to come.

Source: ESA

Posted on by Nancy Atkinson

A New “Drake” Equation for Potential of Life

An image showing microbes living in sandstone in Antarctica (credit: C Cockell)

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The famed Drake equation estimates the number of technologically advanced civilizations that might exist in our Galaxy. But is there a way to mathematically quantify a habitat’s potential for hosting life?
“At present, there is no easy way of directly comparing the suitability of different environments as a habitat for life” said Dr. Axel Hagermann, who is proposing a method to find a “habitability index” at the European Planetary Science Congress.

“The classical definition of a habitable environment,” said Hagermann, “is one that has the presence of a solvent, for example water, availability of the raw materials for life, clement conditions and some kind of energy source, so we tend to define a place as ‘habitable’ if it falls into the area where these criteria overlap on a Venn diagram. This is fine for specific instances, but it gives us no quantifiable way of comparing exactly how habitable one environment is in comparison with another, which I think is very important.”
Drake Equation
Hagermann and colleague Charles Cockell have the ambitious aim of developing a single, normalized indicator of habitability, mathematically describing all the variables of each of the four habitability criteria. Initially, they are focusing on describing all the qualities of an energy source that may help or hinder the development of life.

“Electromagnetic radiation may seem simple to quantify in terms of wavelengths and joules, but there are many things to consider in terms of habitability,” Hagermann said. “For instance, while visible and infrared wavelengths are important for life and processes such as photosynthesis, ultraviolet and X-rays are harmful. If you can imagine a planet with a thin atmosphere that lets through some of this harmful radiation, there must be a certain depth in the soil where the ‘bad’ radiation has been absorbed but the ‘good’ radiation can penetrate. We are looking to be able to define this optimal habitable region in a way that we can say that it is ‘as habitable’ or ‘less habitable’ than a desert in Morocco, for example.”

The pair will be presenting their initial study and asking for feedback from colleagues at the European Planetary Science Congress. “There may be good reasons why such a habitability index is not going to work and, with so many variables to consider, it is not going to be an easy task to develop. However, this kind of index has the potential to be an invaluable tool as we begin to understand more about the conditions needed for life to evolve and we find more locations in our Solar System and beyond that might be habitable.”

Source: Europlanet

Posted on by Nancy Atkinson

This Week’s Where In The Universe Challenge

Here’s this week’s image for the WITU Challenge, to test your visual knowledge of the cosmos. You know what to do: take a look at this image and see if you can determine where in the universe this image is from; give yourself extra points if you can name the spacecraft responsible for the image. We’ll provide the image today, but won’t reveal the answer until tomorrow. This gives you a chance to mull over the image and provide your answer/guess in the comment section. Please, no links or extensive explanations of what you think this is — give everyone the chance to guess.

UPDATE: The answer has been posted below.

The location of this feature sounds like it could be on the Klingon homeworld, but this is actually a crater on Earth. You can find it in southeastern Mongolia, roughly halfway between Ulaanbaatar and Beijing. It is an ancient crater, called Tabun Khara Obo. This recent image was taken by the Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite, acquired August 28, 2009. The crater was first identified as a probable impact crater in 1976, although confirmation of the hypothesis only occurred decades later. Drilling at the site in 2008 revealed rock features consistent with high-speed impacts such as those caused by meteorites.

A few of you had Qapla’ in answering this one. SoH ‘oH intelligent.

Find out more about this image as NASA’s Earth Observatory website, and check back next week for another WITU Challenge!

Posted on by Fraser Cain

Composite Volcano

Mount Fuji - a composite volcano

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Geologists have identified 3 major types of volcanoes. There’s the shield volcano, formed from low viscosity lava that can flow long distances. There are cinder cone volcanoes, which are made by the eruption of lava, ash and rocks that build up around a volcanic vent. But the last type is the composite volcano, and these are some of the most famous volcanoes (and most dangerous) in the world.

A composite volcano is formed over hundreds of thousands of years through multiple eruptions. The eruptions build up the composite volcano, layer upon layer until it towers thousands of meters tall. Some layers might be formed from lava, while others might be ash, rock and pyroclastic flows. A composite volcano can also build up large quantities of thick magma, which blocks up inside the volcano, and causes it to detonate in a volcanic explosion.

Composite volcanoes are fed by a conduit system which taps into a reservoir of magma deep within the Earth. This magma can erupt out of several vents across the composite volcano’s flanks, or from a large central crater at the summit of the volcano.

Some of the most famous volcanoes in the world are composite volcanoes. And some of the most devastating eruptions in history came from them. For example, Mount St. Helens, Mount Pinatubo, and Krakatoa are just examples of composite volcanoes that have erupted. Famous landmarks like Mount Fuji in Japan, Mount Ranier in Washington State, and Mount Kilimanjaro in Africa are composite volcanoes that just haven’t erupted recently.

When large composite volcanoes explode, they can leave behind a collapsed region called a caldera. These are deep, steep-walled depressions which marked the location of the volcano. And it’s in this region that a new composite volcano will build back up again.

Another name for composite volcanoes are stratovolcanoes.

We have written many articles about composite volcanoes for Universe Today. Here’s an article about the recent eruption of Mount Redoubt in Alaska, and here’s an article about Mount Etna.

You can learn more about composite volcanoes from the USGS.

And we have recorded an entire episode of Astronomy Cast just about volcanoes. Listen to it here, Episode 141: Volcanoes, Hot and Cold.