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Category Archives: 20. Life in the Universe

From an article in the New York Times, August 31, 2016:

Geologists in Greenland have discovered evidence for ancient life in rocks that are 3.7 billion years old.

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Credit: Allen Nutman/NYT

They are thought to be stromatolites, layers of sediment packed together by microbial communities living in shallow water. They are some 220 million years more ancient than the oldest previously known fossils, also stromatolites, from the Pilbara region of Western Australia.

The find, if confirmed, would make these fossils the oldest on Earth and may change scientific understanding of the origins of life.

Link: the full NYT article.

From a press release of the SETI Institute, March 30, 2016:

The SETI Institute has inaugurated a greatly expanded hunt for deliberately produced radio signals that would indicate the presence of extraterrestrial intelligence. Over the course of the next two years, it will scrutinize the vicinities of 20,000 so-called red dwarf stars.

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Credit: SETI Institute

 

Red dwarfs are dimmer and cooler than the Sun, but they make up the bulk of stars in the Galaxy, increasing the odds of finding life there. They are also, on average, billions of years older than stars than Sun-like stars, so have had more time to potentially produce intelligent species.

The two-year search will be conducted at the Allen Telescope Array in the Cascade Mountains of northern California. This grouping of 42 antennas can currently observe three stars simultaneously.

Links: Full SETI Institute press release.

From a UC Berkeley press release, July 20, 2015:

The Breakthrough Prize Foundation and its founder, internet investor Yuri Milner, have signed a contract with UC Berkeley to lead a major escalation in the search for extraterrestrial intelligence (SETI). The foundation has committed $100 million over 10 years to UC Berkeley and other participating institutions for a project called Breakthrough Listen, the most comprehensive scientific SETI project yet.

The Breakthrough Prize Foundation has already contracted with two of the world’s largest radio telescopes – the 100-meter Robert C. Byrd Green Bank Telescope in West Virginia and the 64-meter Parkes Telescope in New South Wales, Australia – to devote between 20 and 25 percent of their telescope time to searching for signals from other civilizations. The funding will also allow the Automated Planet Finder at the Lick Observatory near San Jose, CA, to search for optical laser signals from other planets.

For the Breakthrough Listen program, UC Berkeley will build high-speed digital electronics and high-bandwidth signal processing instruments to gather and analyze the radio and optical data collected by the telescopes, and will train the next generation of SETI scientists.

The program will generate vast amounts of data, all of which will be open to the public. Over time this could constitute the largest amount of scientific data ever made available to the public, according to the foundation.

Links: the full UC Berkeley press release, Breakthrough Listen homepage.

In an article in the New York Times, January 31, 2015, Peter Brannen reports on the ongoing debate about what caused the extinction of the non-bird dinosaurs at the end of the Cretaceous period (see A Closer Look 8.5, p. 220).

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Credit: Emiliano Ponzi/NY Times

While to many, the NEO impact theory and the discovery of the Chicxulub impact crater is compelling evidence, some geologists point to enormous floods of lava in India, called the Deccan Traps, as an alternate explanation.

Read more about the debate here.

An article in ScienceNews describes experiments on Earth about making a probe that can penetrate far enough into Europa’s surface ice to figure out what might be in Europa’s invisible ocean.

Credit: JPL-Caltech/NASA

Jupiter’s moon, Europa, looks just as desolate and uninviting as any other place in the outer Solar System. Its frozen façade is colder than the most frigid spot on Earth  by more than 100 degrees Celsius. Blasts of radiation sweep the surface. But beneath Europa’s inhospitable exterior, scientists think a vast ocean of liquid water flows. The moon’s seafloor might also bustle with activity from volcanoes and hydrothermal vents. If chemicals from the surface trickle down through the ice, as some scientists suspect, Europa could hold all the necessary ingredients for life.

Kevin Hand of NASA’s Jet Propulsion Laboratory in Pasadena, CA, says  “You’ve got incredible ecosystems of tube worms and crabs and fish and microbes [on Earth]. It’s anybody’s guess whether or not you’d find tube worms on Europa.”

The idea of exploring this vast ocean has launched a number of scientists on a quest for a space-ready ice drill. Somehow, such a device has to breach the moon’s icy shell — perhaps with blazing hot metal or the jagged teeth of a drill bit — and carry enough power for the job. The device has to be simpler and more reliable than anything used to bore through ice on Earth, and it will have to take care of itself — there’s no way to send a team of engineers to the far edges of the Solar System. And the entire ice-tunneling, power-toting, problem-free package needs to be light enough to launch beyond Earth’s gravitational grip. Research teams are now exploring the different approaches to penetrate, drill, burrow or melt through Europa’s icy shell.

Read more about these varied projects at ScienceNews.

Is Earth the only known world that can support life? In an effort to find life-habitable worlds outside our Solar System, stars similar to our Sun are being monitored for slight light decreases that indicate eclipsing, or transiting, planets (see section 9.2d, pp. 240-243). Many previously-unknown planets are being found, including over 700 worlds recently uncovered by NASA’s Kepler satellite.

Credit: Planetary Habitability Laboratory (UPR Arecibo)

Depicted above in artist’s illustrations are twelve extrasolar planets that orbit in the habitable zones of their parent stars. These exoplanets have the right temperature for water to be a liquid on their surfaces, and so water-based life on Earth might be able to survive on them. Although technology cannot yet detect resident life, finding habitable exoplanets is a step that helps humanity to better understand its place in the cosmos.

Links: APOD for full-size image; Kepler mission website.

On December 4, 2013, the U.S. House of Representatives Committee on Science, Space, and Technology met for a hearing on “Astrobiology: Search for Biosignatures in our Solar System and Beyond”.

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Credit: NASA/Ames/JPL-Caltech

The hearing’s purpose was to examine astrobiology research and the search for signs of life in our Solar System and beyond. It included a general assessment of the multi- and interdisciplinary nature of astrobiology research, including the role astrobiology plays in formulating NASA space missions. It also examined the techniques and capabilities necessary to determine the potential for the existence of biosignatures within our Solar System.

With the discovery of potential Earth-like planets outside of our Solar System, the committee heard three experts discuss what methods are being used to determine if any of these planets may harbour life and explored existing and planned astrobiology research strategies and roadmaps.

Links: House Committee on Science and Technology website, including the witnesses’ testimony in transcript form and an archived webcast of the proceedings.

NASA’s Voyager 1 spacecraft is officially the first human-made object to venture into interstellar space. The 36-year-old probe is about 12 billion miles (19 billion kilometers) from the Sun.

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Credit: NASA/JPL-Caltech

New and unexpected data indicate Voyager 1 has been traveling for about one year through plasma, or ionized gas, present in the space between stars. Voyager is in a transitional region immediately outside the solar bubble, where some effects from our sun are still evident. A report on the analysis of this new data, led by Don Gurnett and the plasma wave science team at the University of Iowa, Iowa City, is published in the journal Science.

Voyager 1 does not have a working plasma sensor, so scientists needed a different way to measure the spacecraft’s plasma environment to make a definitive determination of its location. A coronal mass ejection, a massive burst of solar wind and magnetic fields, that erupted from the Sun in March 2012 provided scientists with the data they needed. When this blast from the Sun eventually overtook Voyager 1 some 13 months later, in April 2013, the plasma around the spacecraft began to vibrate like a violin string. On April 9, Voyager 1’s plasma wave instrument detected the movement. The pitch of the oscillations helped scientists determine the density of the plasma. The particular oscillations meant the spacecraft was bathed in plasma more than 40 times denser than what they had encountered in the outer layer of the heliosphere. This density is that which is expected in interstellar space.

Much more information is available on NASA’s Voyager page, and via this JPL press release, which includes more images and a short video. The sound of interstellar space may be heard here.