Exploring Astrobiology

The first known interstellar object to visit our solar system, 1I/2017 U1 ‘Oumuamua, was discovered Oct. 19, 2017 by the University of Hawaii’s Pan-STARRS1 telescope, funded by NASA’s Near-Earth Object Observations (NEOO) Program, which finds and tracks asteroids and comets in Earth’s neighborhood. While originally classified as a comet, observations revealed no signs of cometary activity after it slingshotted past the Sun on Sept. 9, 2017 at a blistering speed of 196,000 miles per hour (87.3 kilometers per second). It was briefly classified as an asteroid until new measurements found it was accelerating slightly, a sign it behaves more like a comet.

Murchison meteorite, meteorite that fell as a shower of stones (see meteorite shower) in Victoria, Austl., in 1969. More than 100 kg (220 pounds) of the meteorite were collected and distributed to museums all over the world.

The Murchison meteorite is classified as a carbonaceous chondrite. It was pervasively altered by water, probably when it was part of its parent asteroid, and it consists mostly of hydrated clay minerals. Because of the availability of samples and its freedom from contamination with terrestrial material, the meteorite has been widely studied for the organic matter that it contains. Amino acids, alcohols, aldehydes, ketones, amines, kerogens, and other organic compounds have been detected and analyzed. The molecular structures of these organic compounds preclude their origin in biological life on Earth

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Carl Edward Sagan, (born November 9, 1934, Brooklyn, New York, U.S.—died December 20, 1996, Seattle, Washington), American astronomer and science writer. A popular and influential figure in the United States, he was controversial in scientific, political, and religious circles for his views on extraterrestrial intelligence, nuclear weapons, and religion

He was an American astronomer, planetary scientist, cosmologist, astrophysicist, astrobiologist, author, and science communicator. His best known scientific contribution is research on extraterrestrial life, including experimental demonstration of the production of amino acids from basic chemicals by radiation. Sagan assembled the first physical messages sent into space: the Pioneer plaque and the Voyager Golden Record, universal messages that could potentially be understood by any extraterrestrial intelligence that might find them. Sagan argued the now-accepted hypothesis that the high surface temperatures of Venus can be attributed to and calculated using the greenhouse effect.

FOR MORE DETAILS-

https://www.nationalgeographic.com/science/article/140316-carl-sagan-science-galaxies-space

Saturn's largest moon, Titan, is an icy world whose surface is completely obscured by a golden hazy atmosphere. Titan is the second largest moon in our solar system. Only Jupiter's moon Ganymede is larger, by just 2 percent. Titan is bigger than Earth's moon, and larger than even the planet Mercury.This mammoth moon is the only moon in the solar system with a dense atmosphere, and it’s the only world besides Earth that has standing bodies of liquid, including rivers, lakes and seas, on its surface. Like Earth, Titan’s atmosphere is primarily nitrogen, plus a small amount of methane. It is the sole other place in the solar system known to have an earthlike cycle of liquids raining from clouds, flowing across its surface, filling lakes and seas, and evaporating back into the sky (akin to Earth’s water cycle). Titan is also thought to have a subsurface ocean of water

An alternate explanation for life's hypothetical existence on Titan has been proposed: if life were to be found on Titan, it could have originated from Earth in a process called panspermia. It is theorized that large asteroid and cometary impacts on Earth's surface have caused hundreds of millions of fragments of microbe-laden rock to escape Earth's gravity. Calculations indicate that a number of these would encounter many of the bodies in the Solar System, including Titan. On the other hand, Jonathan Lunine has argued that any living things in Titan's cryogenic hydrocarbon lakes would need to be so different chemically from Earth life that it would not be possible for one to be the ancestor of the other. In Lunine's view, presence of organisms in Titan's lakes would mean a second, independent origin of life within the Solar System, implying that life has a high probability of emerging on habitable worlds throughout the cosmos.

The Cassini spacecraft’s numerous gravity measurements of Titan revealed that the moon is hiding an underground ocean of liquid water (likely mixed with salts and ammonia). The European Space Agency’s Huygens probe also measured radio signals during its descent to the surface, in 2005, that strongly suggested the presence of an ocean 35 to 50 miles (55 to 80 kilometers) below the icy ground. The discovery of a global ocean of liquid water adds Titan to the handful of worlds in our solar system that could potentially contain habitable environments. Additionally, Titan’s rivers, lakes and seas of liquid methane and ethane might serve as a habitable environment on the moon’s surface, though any life there would likely be very different from Earth’s life. Thus, Titan could potentially harbor environments with conditions suitable for life—meaning both life as we know it (in the subsurface ocean) and life as we don’t know it (in the hydrocarbon liquid on the surface). Although there is so far no evidence of life on Titan, its complex chemistry and unique environments are certain to make it a destination for continued exploration.

LET'S EXPLORE OUR OWN SOLAR SYSTEM

Many of us have been led, over the years, to believe something that’s not necessarily true. When we wonder about the absence of alien life or the enormity of the universe, we are told that Earth is a world like many others. It is not of tremendous size nor is it located in any special sort of galaxy. The fact that we are the only intelligent life in the universe is such a mystery to us because there is nothing special about our planet. Dr. Frank Drake’s equation arrives at the conclusion that, after taking into consideration seven distinct factors, there should be at least 1,000 civilizations in our galaxy alone. Carl Sagan estimated this number to be 1 million in 1974.

There are two ways to test the Rare Earth hypothesis. Both involve the continued search for life beyond our home. Finding either living microbes or their fossils on other worlds would help confirm that single-celled life appears easily and perhaps even frequently on warm worlds with liquid oceans. The second test is the search for advanced alien civilizations. Large telescopes in space would help us part the heavy and mysterious curtain of uncertainty. In the book Rare Earth by evolutionary biologist Peter Ward and astrobiologist Donald E. Brownlee, the authors emphasize just how much more significant the loss of every animal species is in the light of their hypothesis. If we are at a special moment in time — and in a special place in the great breathy cosmos — where life can exist when all the odds are otherwise against it, then every species of animal on this planet is that much more precious

Panspermia is the astrobiological hypothesis that life exists elsewhere in the universe due to a distribution of microorganisms being inadvertently transported on asteroids, other traveling planetoids, or even spacecraft. Hypotheses of panspermia could both allow us to explain abiogenesis or, in other words, the origin of life and how it may travel from places known to hold living organisms to populate distant galaxies or planets.

When scientists approach the question of how life began on Earth, or elsewhere, their efforts generally involve attempts to understand how non-biological molecules bonded, became increasingly complex, and eventually reached the point where they could replicate or could use sources of energy to make things happen. Ultimately, of course, life needed both.

Interstellar travel refers to the currently theoretical idea of interstellar probes or crewed spacecraft moving between stars or planetary systems in a galaxy. Interstellar travel would be much more difficult than interplanetary spaceflight. Whereas the distances between the planets in the Solar System are less than 30 astronomical units (AU), the distances between stars are typically hundreds of thousands of AU, and usually expressed in light-years. Because of the vastness of those distances, practical interstellar travel based on known physics would need to occur at a high percentage of the speed of light; even so, travel times would be long, at least decades and perhaps millennia or longer.

The speeds required for interstellar travel in a human lifetime far exceed what current methods of space travel can provide. Even with a hypothetically perfectly efficient propulsion system, the kinetic energy corresponding to those speeds is enormous by today's standards of energy development. Moreover, collisions by the spacecraft with cosmic dust and gas can be very dangerous for both passengers and the spacecraft itself.

Kepler-452b (a planet sometimes quoted to be an Earth 2.0 or Earth's Cousin^. based on its characteristics; also known by its Kepler Object of Interest designation KOI-7016.01) is a super-Earth exoplanet orbiting within the inner edge of the habitable zone of the Sun-like star Kepler-452, and is the only planet in the system discovered by Kepler

The exoplanet was identified by the Kepler space telescope, and its discovery was announced by NASA on 23 July 2015.

Scientists with the SETI (Search for Extraterrestrial Intelligence Institute) have already begun targeting Kepler-452b, the first near-Earth-size world found in the habitable zone of a Sun-like star. SETI Institute researchers are using the Allen Telescope Array, a collection of 6-meter (20 feet) telescopes in the Cascade Mountains of California, to scan for radio transmissions from Kepler-452b. As of July 2015, the array has scanned the exoplanet on over 2 billion frequency bands, with no result. The telescopes will continue to scan over a total of 9 billion channels, searching for alien radio signals.