How Common Are Potential Habitable Worlds In Our Galaxy?
Imagine this scenario: You are planning to buy a new house in a nice neighborhood. The schools in the area are good, the neighborhood is very safe, but you want to know the ‘kid friendly’ area (so that your kids can have friends). You drive around, looking at the available houses, watching for any ‘kid signatures’. You notice that a good proportion of the homes in your neighborhood show some ‘potential’ to have kids. Based on your observation, you estimate the percentage of houses with kids. A very similar process is currently being carried out in the field of ‘exoplanets’: planets orbiting other stars. The past two decades have seen a rapid increase in the discoveries of exoplanets (although, if you follow the International Astronomical Union’s definition of a planet, exoplanets are not technically ‘planets’. But that discussion is for another time). Just this year, the number of confirmed exoplanets…
HABITABLE WORLDS AND THE FUTURE OF CIVILIZATIONS
Humans have gazed up at the sky in wonder since before the dawn of civilization, and the age-old question of “are we alone?” has occupied philosophers and priests for centuries on end. Today the interdisciplinary field of astrobiology strives toward an answer to this mystery by examining this history of life on Earth in an effort to search for life elsewhere and better understand our future. Astrobiology is a collaborative effort among scientists of different fields to examine the origin, distribution, and future of life in the universe. Earth is the only known example of an inhabited planet, but this at least provides astrobiologists with a rich geological and biological history to examine the conditions that led to the formation of life. Investigation into the interplay between life and climate can lead toward a more fundamental understanding of exactly what is needed for an environment to be “habitable”. This in…
MEET AN ASTROBIOLOGIST: DR. SANJOY SOM
Geologist, Astrobiologist, Engineer – NASA Ames Research Centre Research Scientist, Director – Blue Marble Space Institute of Science Dr. Sanjoy Som is a research scientist at the Exobiology Branch of NASA Ames Research Center. His is also a systems engineer for Fruit Fly Lab, a scientific program to study fruit flies on the International Space Station. Fruit Fly Lab – 1 launched in December 2014. Broadly, his research involves investigating the connection between geology, geochemistry, and microbiology in geological systems that involve the reaction of water with sea-floor rocks, through a combination of field, laboratory and theoretical studies. His work on investigation of fossil raindrop imprints to study the ancient Earth atmosphere was published in Nature. He is also the CEO of Blue Marble Space, a non-profit organization whose mission is to enable and promote international unity through space exploration. Blue Marble Space has started several outstanding initiatives including…
India joins an international initiative to build world’s largest and most sensitive radio telescope, the Square Kilometre Array (SKA)
Transmission of radio waves or optical light is the most plausible mechanism of communication between us and any intelligent civilization, if existent in the Milky Way. Search for ExtraTerrestrial Intelligence (SETI) is largely dependent on tapping the radio signals coming from other worlds which are several light years away from us. International community of scientists involved in SETI research have been employing huge radio telescopes like the Arecibo radio telescope, the National Radio Astronomy 140 foot radio telescope, the Big Ear telescope and others, to search for radio signals from extraterrestrial civilizations since 1960s. Indian astrophysicists are now all set to make significant contributions in establishment of the world’s largest and most sensitive radio telescope – the Square Kilometre Array (SKA). The SKA radio telescope project will be built in sparsely populated and remote areas of Australia and South Africa, with a total collecting area of approximately one square kilometre,…
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Ice ages in the Southern Hemisphere are influenced primarily by sea surface temperature and atmospheric carbon dioxide rather than changes in the Earth’s orbit
A new international study casts doubt on the leading theory of what causes ice ages around the world — changes in the way the Earth orbits the sun. The researchers found that glacier movement in the Southern Hemisphere is influenced primarily by sea surface temperature and atmospheric carbon dioxide rather than changes in the Earth’s orbit, which are thought to drive the advance and retreat of ice sheets in the Northern Hemisphere. The findings appear in the journal Geology. The study raises questions about the Milankovitch theory of climate, which says the expansion and contraction of Northern Hemisphere continental ice sheets are influenced by cyclic fluctuations in solar radiation intensity due to wobbles in the Earth’s orbit; those orbital fluctuations should have an opposite effect on Southern Hemisphere glaciers. “Records of past climatic changes are the only reason scientists are able to predict how the world will change in the…
Convergent evolution in land to sea transitions in marine predators across major mass extinctions
For more than 250 million years, four-limbed land animals known as tetrapods have repeatedly conquered the Earth’s oceans. These creatures–such as plesiosaurs, penguins and sea turtles–descended from separate groups of terrestrial vertebrates that convergently evolved to thrive in aquatic environments. In a new scientific review, a team of Smithsonian scientists synthesized decades of scientific discoveries to illuminate the common and unique patterns driving the extraordinary transitions that whales, dolphins, seals and other species underwent as they moved from land to sea. Drawing on recent breakthroughs in diverse fields such as paleontology, molecular biology and conservation ecology, their findings offer a comprehensive look at how life in the ocean has responded to environmental change over time. The paper also highlights how evolutionary history informs an understanding of the impact of human activities on marine species today. More information is available in the April 17 issue of Science. Marine tetrapods represent a…
New meltwater is not likely to further lubricate the Greenland Ice Sheet waterslide
Surface meltwater regularly travels to the bottom of the Greenland Ice Sheet and lubricates the flow of the ice into the ocean, but new research indicates that future increasing volumes of this meltwater are unlikely to speed the flow of the ice sheet. How is the Greenland Ice Sheet like an oil drill site? They both host the process of fracking, which is the use of high-pressure fluid to enhance existing cracks. In an oil field, high-pressure drilling fluid widens and deepens cracks in oil-bearing rocks, opening access to more deeply buried fossil fuels. On the Greenland Ice Sheet surface, meltwater fills cracks in the ice. Water is more dense than ice, which creates pressure that pries the cracks open. If there is enough water, a crack can reach the bottom of the ice sheet, opening a path for surface water to flow down to the bottom of the ice…