News from Space: “Life” Molecules Detected in Space!

SagitariusB2The secret to the creation to life in our universe appears to be seeding – the proper elements in the right mix in the right places to form the right kind of molecules. Only then can these molecules evolve chemically into more and more complex structures, thus following a general pathway toward biology. The pathway for life as we know it starts with carbon, but one which is specific organized and structured.

Recently, a team of astronomers  at the ALMA Observatory reported the discovery of this very element while probing distant galaxies. What they found was not just interstellar carbon, but a form of carbon with a branched structure. The discovery was made in the gaseous-star forming region known as Sagittarius B2 – a giant molecular cloud of gas and dust that is located about 390 light years from the center of the Milky Way.

radio-wave-dishesSimple carbon chains aren’t particularly unusual in the cosmos, but complex carbon is a different matter. It is what the researchers, based at Cornell University and the Max Planck Institute, describe as finding a molecular needle in a cosmic haystack. The actual molecule in question is isopropyl cyanide, and it was discerned thanks to the miracle known as radio astronomy.

Within clouds of interstellar dust and gas, elements find themselves shielded from the harsh radiation of open space and are, thus, free to form into more complex arrangements. These molecules don’t just sit there, but instead move around within their cloud-homes and bump into each other. The result of this activity are radio signals which can be detected light-years away – in this case, by radio telescopes here on Earth.

MaxPlanckIns_radiowavepulseEvery molecule has a different radio signal, so it’s possible to pick apart the contents of interstellar junk by examining a cloud’s frequency spectra. NASA, via the Ames Research Center, even maintains a radio-emission frequency database to aid in the tracking of polycyclic aromatic hydrocarbons, a form of molecule thought to contain much of the universe’s carbon stockpiles.

The branching carbon structure of isopropyle cyanide is of particular interest because it’s thought that this arrangement is a step on the way to the production of amino acids, the building blocks of proteins, and hence organic life. The discovery gives weight to the increasingly popular notion that life, or at least many of the key steps leading toward life, actually occurs off-planet.

alien-worldLife on Earth may have been well on its way while the planet was still just space dust waiting to come together into our rock-home. What’s more, the molecules discovered by the ALMA team probably aren’t alone.  As the authors, led by astronomer Arnaud Belloche, wrote:

[Isopropyle cyanide’s] detection therefore bodes well for the presence in the [interstellar medium] (ISM) of amino acids, for which such side-chain structure is a key characteristic… This detection suggests that branched carbon-chain molecules may be generally abundant in the [interstellar medium].

The discovery follows a general progression in recent years adding more and more life-ingredients to our picture of the ISM. A 2011 study revealed that complex organic matter should be created in large volumes from stars, while a 2012 report study found that conditions within the ISM are uniquely suited to the creation of increasingly complex molecules, “step[s] along the path toward amino acids and nucleotides, the raw materials of proteins and DNA, respectively.”

sugar-in-space-molecules_58724_990x742Also in 2012, astronomers working for ALMA found basic sugar molecules hanging out in the gas cloud around IRAS 16293-2422 – a young star located some 400 light-years from Earth. The particular form, glycoaldehyde, is thought to be a key component of the reaction behind the creation of DNA. Indeed, more and more, the universe is looking less and less like a harsh environment in which life must struggle to emerge, to a life factory.

Source: motherboard.vice.com

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