News From Space: Alpha Centauri’s “Superhabitable” World

alpha_centauri_newsScientists and astronomers have learned a great deal about the universe in recent years, thanks to craft like the Kepler space probe and the recently launched Gaian space observatory. As these and other instruments look out into the universe and uncover stars and exoplanets, it not only lets us expand our knowledge of the universe, but gives us a chance to reflect upon the meaning of this thing we call “habitability”.

Basically, our notions of what constitutes a habitable environment are shaped by our own. Since Earth is a life-sustaining environment from which we originated, we tend to think that conditions on another life-giving planet would have to be similar. However, scientists René Heller and John Armstrong contend that there might be a planet even more suitable in this galaxy, and in the neighboring system of Alpha Centauri B.

alpha_centauriBb1For those unfamiliar, Alpha Centauri A/B is a triple star system some 4.3 light years away from Earth, making it the closest star system to Earth. The nice thing about having a hypothetical “superhabitable” planet in this system is that it makes it a lot easier to indulge in a bit of a thought experiment, and will make it that much more easy to observe and examine.

According to the arguments put forward by Heller, of the Department of Physics and Astronomy, McMaster University, Hamilton; and Armstrong, of the Department of Physics, Weber State University in Ogden, this planet may be even more suitable for supporting life than our own. It all comes down to meeting the particulars, and maybe even exceeding them.

habitable_sunsFor example, a habitable planet needs the right kind sun – one that has existed and remained stable for a long time. If the sun in question is too large, then it will have a very short life; and if it’s too small, it might last a long time. But the planet will have to be very close to stay warm and that can cause all sorts of problems, such as a tidally locked planet with one side constantly facing the sun.

Our own sun is a G2-type star, which means it has been alive and stable for roughly 4.6 billion years. However, K-type dwarfs, which are smaller than the Sun, have lives longer than the age of the universe. Alpha Centauri B is specifically a K1V-type star that fits the bill with an estimated age of between 4.85 and 8.9 billion years, and is already known to have an Earth-like planet called Alpha Centauri B b.

alpha_centauriBb2As to the superhabitable planet, assuming it exists, it will be located somewhere between 0.5 and 1.4 astronomical units (46 – 130 million mi, 75 – 209 million km) from Alpha Centauri B. All things being equal, it will have a circular orbit 1. 85 AU (276 million km / 172 million miles) away, which would place it in the middle of the star’s habitable zone.

Also, for a planet to sustain life it has to be geologically active, meaning it has to have a rotating molten core to generate a magnetic field to ward off cosmic radiation and protect the atmosphere from being stripped away by solar winds. A slightly more massive planet with more gravity means more tectonic activity, so a better magnetic field and a more stable climate.

 

PlutoHowever, the most striking difference between the superhabitable world and Earth would be that the former would lack our continents and deep oceans – both of which can be hostile to life. Instead, Heller and Armstrong see a world with less water than ours, which would help to avoid both a runaway greenhouse effect and a snowball planet that an overabundance of water can trigger.

Our superhabitable planet might not even be in the habitable zone. It could be a moon of some giant planet further away. Jupiter’s moon Io is a volcanic hellhole due to tidal heating, but a larger moon that Heller and Armstrong call a “Super Europa” in the right orbit around a gas giant could heat enough to support life even if it’s technically outside the star’s habitable zone.

 

alien-worldAccording to Heller and Armstrong, this world would look significantly different from our own. It would be an older world, larger and more rugged, and would provide more places for life to exist. What water there was would be evenly scattered across the surface in the form of lakes and small, shallow seas. And, it would also be slightly more massive, which would mean more gravity.

This way, the shallow waters would hold much larger populations of more diverse life than is found on Earth, while the temperatures would be more moderated. However, it would be a warmer world than Earth, which also makes for more diversity and potentially more oxygen, which the higher gravity would help with by allowing the planet to better retain its atmosphere.

panspermia1Another point made by Heller and Armstrong is that there may be more than one habitable planet in the Alpha Centauri B system. Cosmic bombardments early in the history of the Solar System is how the Earth got its water and minerals. If life had already emerged on one planet in the early history of the Alpha Centauri B system, then the bombardment might have spread it to other worlds.

But of course, this is all theoretical. Such a planet may or may not exist, and may or may not have triggered the emergence of life on other worlds within the system. But what is exciting about it is just how plausible its existence may prove to be, and how easy it will be to verify once we can get some space probes between here and there.

Just imagine the sheer awesomeness of being able to see it, the images of a super-sized Earth-moon beamed back across light years, letting us know that there is indeed life on worlds besides our own. Now imagine being able to study that life and learning that our conceptions of this too have been limited. What a time that will be! I hope we all live to see it…

 

 

Sources: gizmag.com, universetoday.com

News from Space: Full Model of Exoplanet Created

gliese_581gEver since the Kepler space probe began finding hard evidence of the existence of exoplanets – i.e. planets orbiting suns outside of our Solar System – scientists have been working hard to determine what conditions on these worlds must be like. For instance, it is known that planets that orbit closely to their red dwarf parent suns are tidally locked – meaning they do not rotate on their axis.

This, in turn, has led to the proposal that any watery worlds in the vicinity could form what’s called an “Eyeball Earth.” Being directly under the local star, with one side perpetually facing towards it, the light would be intense enough to melt a circular patch of water, while the rest of the planet would remain locked in a deep freeze. In short, not an ideal situation for supporting life.

eyeball_earthHowever, a new three-dimensional model has been created, thanks to the efforts of two researchers at Peking University. In their research paper, they suggest that ice and oceans on these planets would be dynamic, which is both good and bad. Basically, it means an Eyeball Earth has a narrower habitable zone, but that more of the surface has the potential to support life. It also means that the “eyeball” looks more like a lobster!

This paper represents the next step in scientific analysis of exoplanets. Initially, estimates of habitability – i.e. temperatures that could allow liquid water on the planet surface – were based on a single analysis of the planet’s atmosphere to see how much light reaches the surface. But, in the real world, atmospheres form clouds, distribute heat through winds and convection, and exhibit other sorts of complex behavior.

eyeball_earthThese are the sorts of things that are handled in the full, three-dimensional climate models built to study the Earth. Hence, the Peking research team adapted these same models to handle exoplanets that differed significantly from Earth. But these models didn’t capture a critical part of the distribution of heat on the Earth: the ocean circulation. Instead, it treated the entire ocean as a two-dimensional slab.

The new study corrects for that by using a coupled ocean-atmosphere climate model, the Community Climate System Model version 3. For their study, they used Gliese 581 g, a potentially Earth-like planet orbiting in the habitable zone of an red dwarf star 20 light years away. This planet, coincidentally, is ranked by NASA as being the most Earth-like exoplanet yet seen in the known universe.

Gliese_581_-_2010Critically for the model, it’s close enough to its host star to receive 866 Watts/square meter at the top of its atmosphere (whereas the Earth receives 1,366). Since it is not yet known what Gliese 581 g’s atmosphere looks like, the authors assumed an Earth-like composition, but varied the amount of CO2 to change the intensity of the greenhouse effect. From all this, the planet was assumed to be covered in a deep ocean.

After giving the model 1,100 years to come to equilibrium, the authors sampled a century of its climate. With carbon dioxide concentrations similar to the Earth’s (330 parts per million in the model), the “eyeball” vanished. That’s because ocean currents formed along the equator and brought in ice from the west that split the eyeball into two lobes that flanked the equator – which resemble the claws of the lobster.

eyeball_earth1The currents then transferred heat to the eastern portion of the planet, which melted the ice to form the lobster’s tail. In addition to the ocean current that altered ice distribution, an underwater circulation (similar to the one on Earth) formed, which sent warmer water toward the poles. In the atmosphere, a jet stream also formed over the equator, which also distributed some heat to the unlit side of the planet.

Ultimately, the new model suggests the habitable zone of watery planets near red dwarfs is a bit more narrow than previous studies had suggested. The good news is that, in this model, the ice never got more than 3m thick on the dayside of the planet. That’s thin enough to allow light to reach the water underneath, meaning photosynthesis is a possibility over the entire dayside of the planet.

OceanPlanetAlthough this model is a major improvement, it still lacks a key feature that’s likely to exist on planets – namely continents, or at least features on the seafloor that differ greatly in height. These will radically alter the currents on the planet, and thus radically alter the distribution of heat within the ocean. Unfortunately, this information is even harder to come by at present than atmospheric conditions.

So for the time being, all we really know about Gliese 581 g and other similar exoplanets is that their surfaces are icy, but habitable – not unlike the Jovian moon Europa. However, that is not to say that we won’t have more information in the near future. With Kepler still in operation and the Gaia space observatory now in space, we might be able to construct more detailed models of nearby exoplanets in the near future.

Also a coincidence, Gliese 581 g just happens to be the setting of my writers group’s upcoming anthology, known as Yuva. And with this latest bit of info under our belts (basically, that the entire planet is a big, watery ball), I imagine we’ll have to adjust our stories somewhat!

Source: arstechnica.com

Looking Forward: Science Stories to Watch for in 2014

BrightFutureThe year of 2013 was a rather big one in terms of technological developments, be they in the field of biomedicine, space exploration, computing, particle physics, or robotics technology. Now that the New Year is in full swing, there are plenty of predictions as to what the next twelve months will bring. As they say, nothing ever occurs in a vacuum, and each new step in the long chain known as “progress” is built upon those that came before.

And with so many innovations and breakthroughs behind us, it will be exciting to see what lies ahead of us for the year of 2014. The following is a list containing many such predictions, listed in alphabetical order:

Beginning of Human Trials for Cancer Drug:
A big story that went largely unreported in 2013 came out of the Stanford School of Medicine, where researchers announced a promising strategy in developing a vaccine to combat cancer. Such a goal has been dreamed about for years, using the immune system’s killer T-cells to attack cancerous cells. The only roadblock to this strategy has been that cancer cells use a molecule known as CD47 to send a signal that fools T-cells, making them think that the cancer cells are benign.

pink-ribbonHowever, researchers at Stanford have demonstrated that the introduction of an “Anti-CD47 antibody” can intercept this signal, allowing T-cells and macrophages to identify and kill cancer cells. Stanford researchers plan to start human trials of this potential new cancer therapy in 2014, with the hope that it would be commercially available in a few years time. A great hope with this new macrophage therapy is that it will, in a sense, create a personalized vaccination against a patient’s particular form of cancer.

Combined with HIV vaccinations that have been shown not only to block the acquisition of the virus, but even kill it, 2014 may prove to be the year that the ongoing war against two of the deadliest diseases in the world finally began to be won.

Close Call for Mars:
A comet discovery back in 2013 created a brief stir when researchers noted that the comet in question – C/2013 A1 Siding Springs – would make a very close passage of the planet Mars on October 19th, 2014. Some even suspected it might impact the surface, creating all kinds of havoc for the world’s small fleet or orbiting satellites and ground-based rovers.

Mars_A1_Latest_2014Though refinements from subsequent observations have effectively ruled that out, the comet will still pass by Mars at a close 41,300 kilometers, just outside the orbit of its outer moon of Deimos. Ground-based observers will get to watch the magnitude comet close in on Mars through October, as will the orbiters and rovers on and above the Martian surface.

Deployment of the First Solid-State Laser:
The US Navy has been working diligently to create the next-generation of weapons and deploy them to the front lines. In addition to sub-hunting robots and autonomous aerial drones, they have also been working towards the creation of some serious ship-based firepower. This has included electrically-powered artillery guns (aka. rail guns); and just as impressively, laser guns!

Navy_LAWS_laser_demonstrator_610x406Sometime in 2014, the US Navy expects to see the USS Ponce, with its single solid-state laser weapon, to be deployed to the Persian Gulf as part of an “at-sea demonstration”. Although they have been tight-lipped on the capabilities of this particular directed-energy weapon,they have indicated that its intended purpose is as a countermeasure against threats – including aerial drones and fast-moving small boats.

Discovery of Dark Matter:
For years, scientists have suspected that they are closing in on the discovery of Dark Matter. Since it was proposed in the 1930s, finding this strange mass – that makes up the bulk of the universe alongside “Dark Energy” – has been a top priority for astrophysicists. And 2014 may just be the year that the Large Underground Xenon experiment (LUX), located near the town of Lead in South Dakota, finally detects it.

LUXLocated deep underground to prevent interference from cosmic rays, the LUX experiment monitors Weakly Interacting Massive Particles (WIMPs) as they interact with 370 kilograms of super-cooled liquid Xenon. LUX is due to start another 300 day test run in 2014, and the experiment will add another piece to the puzzle posed by dark matter to modern cosmology. If all goes well, conclusive proof as to the existence of this invisible, mysterious mass may finally be found!

ESA’s Rosetta Makes First Comet Landing:
This year, after over a decade of planning, the European Space Agency’s Rosetta robotic spacecraft will rendezvous with Comet 67P/Churyumov-Gerasimenko. This will begin on January 20th, when the ESA will hail the R0setta and “awaken” its systems from their slumber. By August, the two will meet, in what promises to be the cosmic encounter of the year. After examining the comet in detail, Rosetta will then dispatch its Philae lander, equipped complete with harpoons and ice screws to make the first ever landing on a comet.

Rosetta_and_Philae_at_comet_node_full_imageFirst Flight of Falcon Heavy:
2014 will be a busy year for SpaceX, and is expected to be conducting more satellite deployments for customers and resupply missions to the International Space Station in the coming year. They’ll also be moving ahead with tests of their crew-rated version of the Dragon capsule in 2014. But one of the most interesting missions to watch for is the demo flight of the Falcon 9 Heavy, which is slated to launch out of Vandenberg Air Force Base by the end of 2014.

This historic flight will mark the beginning in a new era of commercial space exploration and private space travel. It will also see Elon Musk’s (founder and CEO of Space X, Tesla Motors and PayPal) dream of affordable space missions coming one step closer to fruition. As for what this will make possible, well… the list is endless.

spaceX-falcon9Everything from Space Elevators and O’Neil space habitats to asteroid mining, missions to the Moon, Mars and beyond. And 2014 may prove to be the year that it all begins in earnest!

First Flight of the Orion:
In September of this coming year, NASA is planning on making the first launch of its new Orion Multi-Purpose Crew Vehicle. This will be a momentous event since it constitutes the first step in replacing NASA’s capability to launch crews into space. Ever since the cancellation of their Space Shuttle Program in 2011, NASA has been dependent on other space agencies (most notably the Russian Federal Space Agency) to launch its personnel, satellites and supplies into space.

orion_arrays1The test flight, which will be known as Exploration Flight Test 1 (EFT-1), will be a  short uncrewed flight that tests the capsule during reentry after two orbits. In the long run, this test will determine if the first lunar orbital mission using an Orion MPCV can occur by the end of the decade. For as we all know, NASA has some BIG PLANS for the Moon, most of which revolve around creating a settlement there.

Gaia Begins Mapping the Milky Way:
Launched on from the Kourou Space Center in French Guiana on December 19thof last year, the European Space Agency’s Gaia space observatory will begin its historic astrometry mission this year. Relying on an advanced array of instruments to conduct spectrophotometric measurements, Gaia will provide detailed physical properties of each star observed, characterising their luminosity, effective temperature, gravity and elemental composition.

Gaia_galaxyThis will effectively create the most accurate map yet constructed of our Milky Way Galaxy, but it is also anticipated that many exciting new discoveries will occur due to spin-offs from this mission. This will include the discovery of new exoplanets, asteroids, comets and much more. Soon, the mysteries of deep space won’t seem so mysterious any more. But don’t expect it to get any less tantalizing!

International Climate Summit in New York:
While it still remains a hotly contested partisan issue, the scientific consensus is clear: Climate Change is real and is getting worse. In addition to environmental organizations and agencies, non-partisan entities, from insurance companies to the U.S. Navy, are busy preparing for rising sea levels and other changes. In September 2014, the United Nations will hold another a Climate Summit to discuss what can be one.

United-Nations_HQThis time around, the delegates from hundreds of nations will converge on the UN Headquarters in New York City. This comes one year before the UN is looking to conclude its Framework Convention on Climate Change, and the New York summit will likely herald more calls to action. Though it’ll be worth watching and generate plenty of news stories, expect many of the biggest climate offenders worldwide to ignore calls for action.

MAVEN and MOM reach Mars:
2014 will be a red-letter year for those studying the Red Planet, mainly because it will be during this year that two operations are slated to begin. These included the Indian Space Agency’s Mars Orbiter Mission (MOM, aka. Mangalyaan-1) and NASA’ Mars Atmosphere and Volatile EvolutioN (MAVEN) mission, which are due to arrive just two days apart – on September 24th and 22nd respectively.

mars_lifeBoth orbiters will be tasked with studying Mars’ atmosphere and determining what atmospheric conditions looked like billions of years ago, and what happened to turn the atmosphere into the thin, depleted layer it is today. Combined with the Curiosity and Opportunity rovers, ESA’s Mars Express,  NASA’s Odyssey spacecraft and the Mars Reconnaissance Orbiter, they will help to unlock the secrets of the Red Planet.

Unmanned Aircraft Testing:
A lot of the action for the year ahead is in the area of unmanned aircraft, building on the accomplishments in recent years on the drone front. For instance, the US Navy is expected to continue running trials with the X-47B, the unmanned technology demonstrator aircraft that is expected to become the template for autonomous aerial vehicles down the road.

X-47BThroughout 2013, the Navy conducted several tests with the X-47B, as part of its ongoing UCLASS (Unmanned Carrier Launched Airborne Surveillance and Strike) aircraft program. Specifically, they demonstrated that the X-47B was capable of making carrier-based take offs and landings. By mid 2014, it is expected that they will have made more key advances, even though the program is likely to take another decade before it is fully realizable.

Virgin Galactic Takes Off:
And last, but not least, 2014 is the year that space tourism is expected to take off (no pun intended!). After many years of research, development and testing, Virgin Galactic’s SpaceShipTwo may finally make its inaugural flights, flying out of the Mohave Spaceport and bringing tourists on an exciting (and expensive) ride into the upper atmosphere.

spaceshiptwo-2nd-flight-2In late 2013, SpaceShipTwo and passed a key milestone test flight when its powered rocket engine was test fired for an extended period of time and it achieved speeds and altitudes in excess of anything it had achieved before. Having conducted several successful glide and feathered-wing test flights already, Virgin Galactic is confident that the craft has what it takes to ferry passengers into low-orbit and bring them home safely.

On its inaugural flights, SpaceShipTwo will carry two pilots and six passengers, with seats going for $250,000 a pop. If all goes well, 2014 will be remembered as the year that low-orbit space tourism officially began!

Yes, 2014 promises to be an exciting year. And I look forward to chronicling and documenting it as much as possible from this humble little blog. I hope you will all join me on the journey!

Sources: Universetoday, (2), med.standford.edu, news.cnet, listosaur, sci.esa.int