Searching for Alien Life? Try Failed Stars

This artist's illustration shows a brown dwarf with a disk of planet-forming material around it. Brown dwarfs are bodies without enough mass to ignite nuclear fusion and become stars. 
CREDIT: NASA/JPL-Caltech

The search for alien life usually focuses on planets around other stars. But a lesser-known possibility is that life has sprung up on planets that somehow were ejected from their original solar systems and became free-floating in the universe, as well as on small bodies called sub-brown dwarfs, which are stars so small and dim they are not really stars at all, but function more like planets.

Studies show these bodies could potentially host atmospheres and surfaces where some form ofextraterrestrial life could take hold.

Researcher Viorel Badescu of the Polytechnic University of Bucharest in Romania recently investigated the possibilities for life on free-floating planets (FFPs) and sub-brown dwarfs (SBDs) that might containlakes of the chemical ethane. He found that such life is not impossible, though it would be significantly different from life on Earth.

His findings were detailed in the August 2010 issue of the journal Planetary and Space Science.

Failed stars

Sub-brown dwarfs are not large enough to generate the nuclear fusion that powers normal stars. Having failed as stars, they slowly radiate their internal thermal energy as heat and very dim light – hence, they are extremely hard to detect. Both free-floating planets and sub-brown dwarfs don't always orbit around a parent star, and can be found in interstellar space.

Lacking a star, life on FFPs and SBDs would have to rely on the body's internal heat and the decay of radioactive elements for energy. "One may expect a rather stable heat release for long periods of time, exceeding two or three times the present age of the solar system," said Badescu. Though meager, this heat could be trapped on the object by an optically thick atmosphere.

But life needs more than just heat to thrive. Another important ingredient for habitability is a solvent – a liquid environment where important chemical reactions can occur. Life on Earth uses water as a solvent, but that's not the only option.

"Synthesis of observational data makes it possible to conceive chemical reactions that might support life involving non-carbon compounds, occurring in solvents other than water," Badescu wrote in his paper.

In particular, Badescu found that ethane – a compound of carbon and hydrogen – could function well as a solvent for alien life. [5 Bold Claims of Alien Life]

In this illustration, twin brown dwarfs orbit each other. Despite the name "brown dwarf", these objects cool and change over time, and therefore do not have a definitive color. 
CREDIT: NASA/JPL-Caltech

 

 

Life without water

It seems odd to consider the possibility of life on an object more massive than Jupiter or Saturn, especially since most scientists think such gas giant planets -- with their high radiation, hostile atmospheres and potential lack of a planetary surface -- would not harbor life as we know it. 

But Badescu said that some sub-brown dwarfs might have lakes or oceans of liquid ethane that could prove quite homey to alien microbes.

The main difference between water and ethane for use as a solvent is that water is a polar molecule, meaning one end of the molecule is positively charged, and one end of it is negatively charged. This has proven integral to Earth life, because the polar properties of water enable certain kinds of molecules to dissolve easily in water, while others remain stable.

The molecules that code for life – DNA and RNA – have electrical charge properties that allow them to change their internal structure – the specific order of the base molecules within them – and still have the same overall physical properties. This is all enabled by the way their charge properties interact with the polar quality of water.

That would not be the case with ethane, which is a non-polar molecule. With DNA and RNA in this situation, "small changes in molecular structure may create large changes in molecular behavior," Badescu said. "That is not acceptable in an encoding biopolymer that must support Darwinian evolution, in which case, the molecule's physical properties must remain relatively constant when the informational content changes."

However, the challenge is not insurmountable – a completely different type of molecule could be used to code life's blueprint on a FFP or SBD.

Scientists think sub-brown dwarfs or free-floating planets might contain lakes of ethane that could host life. This artist's concept shows similar lakes of ethane thought to exist on Saturn's moon Titan. 
CREDIT: NASA/Karl Kofoed

 

 

Searching for life

Ultimately, free-floating planets and sub-brown dwarfs could prove a fertile place to look for extraterrestrial creatures.

Besides their habitable qualities, these bodies seem to be quite common in the universe. Sub-brown dwarfs weighing between 1 and 13 Jupiter masses may be about as common as stars, Badescu said.

"The total number of FFPs and SBDs may exceed the number of stars by two orders of magnitude, although most of them should be low-mass rock/ice planetary embryos ejected from planetary systems in formation," i.e. not the type with large gaseous atmospheres that would retain the heat required for life, Badescu said. "Thus, it might be conceivable that FFPs and SBDs are the most common sites of life in the universe."

Given this fact, he advocated ramping up our efforts to search for free-floating planets and sub-brown dwarfs and to characterize them to determine which might be habitable.

"Present day technology does not allow a systematic search for habitable FFPs and SBDs," Badescu said. "However, the existing observation programs of young star forming regions should be supplemented with activities related to FFP and SBD identification and characterization."

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Venus and the Moon to Shine Together Thursday Morning

This sky map shows how Venus and the crescent moon will appear just before sunrise on March 31, 2011 as viewed under clear morning conditions.
CREDIT: Starry Night Software

Early-bird skywatchers graced with clear weather tomorrow morning (March 31) will get a celestial treat before sunrise, when Venus and the moon appear together in the east-southeast sky. 

Venus will be low onthe horizon,a brilliant “morning star,” with a lovely waning crescent moon hovering less than 5 degrees (about half the width of a human fist) above the planet and to its left. The moon will be just 9 percent illuminated, since it is less than three days before its new phase. [Moon Phases Explained]

While not an exceptionally close conjunction, the cosmic event should not disappoint skywatchers. Venus and the moon are the two brightest luminaries of the night sky, and the pair should make for a striking sight in the dawn twilight.

How to see Venus and the moon

Make sure there are no tall obstructions like buildings or trees, since by sunup Venus will only be about 12 degrees above the horizon. Your clenched fist held at arm’s length covers about 10 degrees of the sky, so Venus will only be a little higher than one fist above the horizon at daybreak. The moon will appear a bit above that.

This sky map of Venus and the moon shows how they will appear during their March 31 rendezvous.

Considering that we’re now back on daylight saving time, and sunrise is coming rather late again, there will no doubt will be a number of morning commuters heading out to work and school who might wonder what that “bright light” below and to the right of the slender sliver of moon is. [Amazing Moon Photos]

Then again, those who only now might notice Venus probably haven’t been paying much attention to what has been visible in the early morning skyof late. 

Dance of Venus

Venus has been putting on a dazzling show in the pre-sunrise eastern sky since November. During December and January, it soared high into the sky and was visible for nearly four hours before sunrise.

But from now through the month of April, Venus will linger low in the eastern predawn sky. The brilliant orb will rise like clockwork just over an hour before sunrise, but still can be easily identified as the brightest thing besides the moon.

Late in April, Venus will be joined by three other planets – Mercury, Mars and Jupiter.

All four planets ultimately will converge in an unusual planetary gathering that will persist through much of May.But more on that next month.

 

Do you plan to photograph Venus and the moon? Do you have skywatching photos you'd like to share with SPACE.com? If so, feel free to send them to managing editor Tariq Malik at: tmalik[at]space[dot]com for potential galleries or stories.

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York.

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Cosmic Rose Blooms in Star Cluster Photo

The star cluster NGC 371 appears in this new image from ESO’s Very Large Telescope. 
CREDIT: ESO/Manu Mejias, images

A bright star cluster surrounded by iridescent red gas looks like a blooming cosmic rose in a new photo from the European Southern Observatory's Very Large Telescope.

The photo depicts the star cluster NGC 371, a stellar nursery in our neighboring galaxy the Small Magellanic Cloud, a dwarf galaxy about 200 000 light-years from Earth. Such regions of ionized hydrogen — known as HII regions — are sites of recent star birth. [More Photos by the Very Large Telescope]

NGC 371 is an open cluster surrounded by a nebula. The stars in open clusters all originate from the same diffuse HII region, and over time the majority of the hydrogen is used up by star formation, leaving behind a shell of hydrogen such as the one in this image, along with a cluster of hot young stars.

This cluster is of particular interest to astronomers due to the unexpectedly large number of variable stars it contains. These are stars that change in brightness over time. Variable stars play a pivotal role in astronomy: Some types are invaluable for determining distances to far-off galaxies and the age of the universe.

The Small Magellanic Cloud contains stars at all stages of their evolution, from the super-bright young stars found in the NGC 371 cluster to the supernova remnants of long-dead stars.

The energetic young stars emit copious amounts of ultraviolet radiation, causing surrounding gas, such as leftover hydrogen from the stars' parent nebula, to light up with a colorful glow that extends for hundreds of light-years in every direction.

This new image was created using the FORS1 instrument on the Very Large Telescope at the Paranal Observatory in Chile's Atacama desert.

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Japanese Spaceship Loaded with Garbage Burns Up in Earth's Atmosphere

An unmanned Japanese space cargo ship met its fiery demise overnight when it intentionally re-entered the Earth’s atmosphere late Tuesday (March 29) one day after its departure from the International Space Station.

The robotic spacecraft, an H-2 Transfer Vehicle called Kounotori 2 (which means "White Stork" 2), was destroyed to dispose of itself and its cargo of space station trash after a successful two-month mission to the orbiting laboratory.

Along with the station trash aboard Kounotori 2, a high-tech sensor onboard the cargo ship successfully monitored the hot and fiery details of the spacecraft’s plunge to destruction into the South Pacific Ocean. It related its data via satellite to researchers for later analysis. The spacecraft also carried three paper cranes folded by the space station's three-person crew as a symbol of hope for the victims of the massive Japanese earthquake and tsunami that struck the country on March 11.

 

The sensor on Kounotori 2 – a small and autonomous device called the Re-entry Breakup Recorder, or REBR for short – recorded temperature, acceleration, rotational rate and other data during the spacecraft's high dive into Earth’s atmosphere.

“REBR collected data during the breakup of the Kounotori 2 vehicle and successfully 'phoned home' that data prior to final impact,” said William Ailor, Director of the Center for Orbital and Reentry Debris Studies at The Aerospace Corporation in El Segundo, Calif. “In fact, it is still transmitting while floating in the ocean.”

Recovery of the device is not planned.

REBR was made possible by using tiny sensors and miniature cell phone technology, built as basically a satellite phone with a heat shield. [Photos: Spotting Spaceships From Earth]

Ailor told SPACE.com that analysis of the data will take six to eight weeks. The Aerospace Corporation designed REBR to collect data during atmospheric reentries of space hardware in order to help understand breakup and increase the safety of such reentries. 

The REBR project was supported by the U.S. Air Force, NASA, and the Boeing Company. The first flight test of the small, autonomous device was coordinated by the Department of Defense’s Space Test Program. A second test will be REBR’s reentry aboard the European Autonomous Transfer Vehicle 2, called Johannes Kepler, in early June.

Kounotori 2, also known as HTV-2, was the second disposable H-2 Transfer Vehicle built by the Japan Aerospace Exploration Agency (JAXA) to ferry tons of cargo to the International Space Station. The first HTV spacecraft, HTV-1, visited the station in 2009.

 

"The HTV-2 carried various important cargo, including spare units of the external ISS system and potable water for the crew, which has been mostly transported by the space shuttle up to now," JAXA President Keiji Tachikawa said in a statement. "I believe that this success proves that the HTVs are reliable transportation vehicles essential for maintaining the ISS, and that Japan, as an international partner of the ISS, is eligible to play an important role for ISS operations."

The spacecraft are about 33 feet (10 meters) long and 14 feet (4.4 m) wide. They can carry cargo inside a pressurized compartment – which astronauts can retrieve after docking – as well as haul spare station parts on an unpressurized pallet to be retrieved by a robotic arm.

JAXA's HTV spacecraft are part of an international robot spaceship fleet that regularly resupplies the space station. Russia's unmanned Progress spacecraft and Europe's ATV vehicles also make supply shipments.

The Kounotori 2 spacecraft launched in January and arrived at the station on Jan. 27. The next HTV spacecraft is expected to fly in January 2012.

Leonard David has been reporting on the space industry for more than five decades. He is past editor-in-chief of the National Space Society's Ad Astra and Space World magazines and has written for SPACE.com since 1999.

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European Rocket to Launch New Satellites Today

Communications satellites for the Middle East and Africa are buttoned up for blastoff today (March 30) inside an Ariane 5 rocket.

The 165-foot-tall rocket is scheduled to lift off at 2145 GMT (5:45 p.m. EDT) from the ELA-3 launch zone at the Guiana Space Center, a French-run spaceport in Kourou, French Guiana.

The Ariane 5 launcher has 67 minutes to get off the ground Wednesday evening or else wait until another day.

Positioned atop a mobile rail platform, the workhorse expendable rocket rolled from the space center's final assembly building to the launch pad Tuesday. Workers planned to make electrical, communications and fueling connections between the ground and the launcher later Tuesday.  [Spaceflight Now's Ariane 5 Mission Archive]

The European rocket will haul the Yahsat 1A and Intelsat New Dawn communications satellites into an egg-shaped transfer orbit stretching more than 22,200 miles above Earth.

It will take 35 minutes for the Ariane 5 to deploy both satellites in the correct orbit.

First to separate from the Ariane 5 will be the Yahsat 1A spacecraft.

The high-powered Yahsat 1A satellite will be located in geosynchronous orbit along the equator at 52.5 degrees east longitude, putting the craft in range of communications customers across the Middle East, Africa, Europe and Southwest Asia.

Operated by Al Yah Satellite Communications Co. of Abu Dhabi, Yahsat 1A will provide direct-to-home television programming, secure Ka-band communications capacity for government and military applications in the United Arab Emirates and other nations.

Yahsat 1A will also support communications links for corporate data networks and Internet trunking, according to the satellite operator.

"The launch of Yahsat's first satellite is a fantastic achievement and a moment of pride for all involved," said Jassem Mohamed Al Zaabi, Yahsat's CEO. "By expanding our satellite communication capabilities, we are supporting the development of an advanced information and communications infrastructure that will drive economic diversification and social progress across the whole region."

Weighing 13,150 pounds at launch, Yahsat 1A is based on the Eurostar E3000 satellite bus from Astrium. Thales Alenia Space of France built Yahsat 1A's Ku-band, C-band and Ka-band communications payload.

Yahsat 1A is designed to work in space for more than 15 years.

Intelsat New Dawn will ride in the lower position during the Ariane 5's ascent into orbit. Once Yahsat 1A deploys, the rocket will jettison a Sylda dual-payload adapter to make way for the Intelsat satellite's release.

The $250 million satellite was built by Orbital Sciences Corp. and is based on that firm's Star 2 platform.

The 6,600-pound spacecraft will link Africa, Western Europe, the Middle East and Pakistan through Ku-band and C-band transponders and antennas. Intelsat New Dawn is geared for wireless broadband, television and other media applications.

Mostly financed by South African investment houses, Intelsat New Dawn is one of four satellites Intelsat is launching between 2010 and 2012 to bolster the company's presence in Africa.

Intelsat New Dawn will be parked at 32.8 degrees east longitude, where it will operate for more than 15 years.

Final countdown procedures are scheduled to begin at 1015 GMT (6:15 a.m. EDT). A check of electrical systems is expected around 1415 GMT (10:15 a.m. EDT), and the launch team will begin fueling the rocket with super-cold liquid hydrogen and liquid oxygen propellants at about 1645 GMT (12:45 p.m. EDT).

Chilldown conditioning of the Vulcain 2 first stage engine will occur at 1845 GMT (2:45 p.m. EDT), and a communications check between the rocket and ground telemetry, tracking and command systems is scheduled for 2035 GMT (4:35 p.m. EDT).

The computer-controlled synchronized countdown sequence will begin seven minutes before launch to pressurize propellant tanks, switch to on-board power and take the rocket's guidance system to flight mode.

The Vulcain 2 engine will ignite as the countdown clock reaches zero, followed by a health check and ignition of the Ariane 5's solid rocket boosters seven seconds later to send the 1.7 million-pound launcher skyward.

Five seconds after blastoff, the rocket will begin pitching east from the ELA-3 launch pad, surpassing the speed of sound less than a minute into the mission. The Ariane 5's twin solid rocket boosters will jettison 2 minutes and 21 seconds after liftoff.

Once above the dense atmosphere, the launcher's payload fairing will fall away at an altitude of nearly 70 miles. The Ariane 5's first stage will shut down at 8 minutes, 53 seconds, followed moments later by stage separation and ignition of the hydrogen-fueled cryogenic HM7B upper stage engine.

The rocket's upper stage will fire for more than 16 minutes, accelerating to a velocity of 5.8 miles per second to reach an orbit with a planned high point of 22,236 miles and a targeted low point of 155 miles.

The release of Yahsat 1A is scheduled for 27 minutes, 27 seconds. The rocket's barrel-shaped Sylda 5 dual-payload adapter will be jettisoned a few minutes later.

Intelsat New Dawn will separate from the lower portion of the payload stack at 35 minutes, 2 seconds.

Click here for Spaceflight Now's coverage of rocket launches and all Arianespace and other spaceflights.

Copyright 2011 SpaceflightNow.com, all rights reserved.

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NASA nixes James Cameron Mars 3D camera

James Cameron (right) inspects a mast camera system designed for NASA's Curiosity Mars rover.

(Credit: NASA)

NASA has shelved a special 3D camera system that was developed with filmmaker James Cameron for the $2.4 billion Mars rover Curiosity, which is due to launch later this year.

The zoom mast camera for Curiosity was nixed because there isn't enough time to prepare it for launch in November, according to developer Malin Space Science Systems and NASA.

The system was in the final stages of development, but time ran out. Technical difficulties prevented engineers from delivering it as scheduled last December. The system did not work as well as the fixed focal length cameras now installed on Curiosity, Malin said.

The Fixed Focal Length Mast Camera (Mastcam) has two cameras--a 100-millimeter telephoto lens and a 34-millimeter wide-angle lens.

"While Curiosity won't benefit from the 3D motion imaging that the zooms enable, I'm certain that this technology will play an important role in future missions," Cameron was quoted as saying. "In the meantime, we're certainly going to make the most of our cameras that are working so well on Curiosity right now."

Curiosity's mission is to make observations on Mars and help assess whether the planet could support microbial life.

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01.Entropy

After some time, this cold glass
will reach thermal equilibrium

Perhaps there’s no better way to understand entropy than to grasp the second law of thermodynamics, and vice versa. This law states that the entropy of an isolated system that is not in equilibrium will increase as time progresses until equilibrium is finally achieved.

Let’s try to elaborate a little on this equilibrium thing. Note that in the succeeding examples, we’ll assume that they’re both isolated systems.

First example. Imagine putting a hot body and a cold body side by side. What happens after some time? That’s right. They both end up in the same temperature; one that is lower than the original temperature of the hotter one and higher than the original temperature of the colder one.

Second example. Ever heard of a low pressure area? It’s what weather reporters call a particular region that’s characterized by strong winds and perhaps some rain. This happens because all fluids flow from a region of high pressure to a region of low pressure. Thus, when the fluid, air in this case, comes rushing in, they do so in the form of strong winds. This goes on until the pressures in the adjacent regions even out.

In both cases, the physical quantities which started to be uneven between the two bodies/regions even out in the end, i.e., when equilibrium is achieved. The measurement of the extent of this evening-out process is called entropy.

During the process of attaining equilibrium, it is possible to tap into the system to perform work, as in a heat engine. Notice, however, that work can only be done for as long as there is a difference in temperature. Without it, like when maximum entropy has already been achieved, there is no way that work can be performed.

Since the concept of entropy applies to all isolated systems, it has been studied not only inphysics but also in information theory, mathematics, as well as other branches of science and applied science.

Because the accepted view of the universe is that of one that is finite, then it can very well be considered as a closed system. As such, it should also be governed by the second law of thermodynamics. Thus, like in all isolated systems, the entropy of the universe is expected to be increasing.

So what? Well, also just like all isolated systems, the universe is therefore also expected to end up in a useless heap in equilibrium, a.k.a. a heat death, wherein energy can no longer be extracted from anymore. To give you some relief, not everyone involved in the study of cosmology is totally in agreement with entropy’s so-called role in the grand scheme of things though.

You can read more about entropy here in Universe Today. Want to know why time might flow in one direction? Have you ever thought about the time before the Big Bang? The entire entropy concept plays an important role in understanding them.

There’s more about entropy at NASA and Physics World too. Here are a couple of sources there:

• Entropy of a Gas
• Max Planck: The Reluctant Revolutionary

Here are two episodes at Astronomy Cast that you might want to check out as well:

• Avoiding the Heat Death, Orbiting Galaxies, and the Dangers of Space Radiation
• Black black holes, Unbalancing the Earth, and Space Pollution

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