Weekly Space Hangout – April 14, 2017: Brad Peterson and LUVOIR

Host: Fraser Cain (@fcain)

Special Guest:
This week’s special guest is Brad Peterson. Brad is a returning guest, and since his last appearance, he has been asked by NASA to serve as a community co-chair, with Debra Fischer of Yale, for the Science and Technology Definition Team for the Large Ultraviolet, Optical, and Infrared Surveyor (LUVOIR).

Brad has carried out research on active galactic nuclei for his entire career. He has been developing the technique of reverberation mapping for over 25 years. He is currently on appointment at STScI as Distinguished Visiting Astronomer, after retiring from the faculty of The Ohio State University in 2015 with 35 years of service, the last nine as chair of the Department of Astronomy. He is also a member of the NASA Advisory Council, for which he chairs the Science Committee. He was recently named chair-elect for the Astronomy Section of the AAAS.

Guests:

Morgan Rehnberg (MorganRehnberg.com / @MorganRehnberg ChartYourWorld.org)

Their stories this week:

Updates on ocean worlds

A half-trillion dollar trip to Mars?

Could an asteroid strike be the source of RNA?

We use a tool called Trello to submit and vote on stories we would like to see covered each week, and then Fraser will be selecting the stories from there. Here is the link to the Trello WSH page (http://bit.ly/WSHVote), which you can see without logging in. If you’d like to vote, just create a login and help us decide what to cover!

Announcements:
On Friday, May 12, the WSH will welcome authors Michael Summers and James Trefil to the show to discuss their new book, Exoplanets: Diamond Worlds, Super Earths, Pulsar Planets and the New Search for Life Beyond Our Solar System. In anticipation of their appearance, the WSH Crew is pleased to offer our viewers a chance to win one of two hard cover copies of Exoplanets. Two winners will be drawn live by @fraser during our show on May 12th. To enter for a chance to win a copy of Exoplanets, send an email to: [email protected] with the Subject: Exoplanets. Be sure to include your name and email address in the body of your message so that we can contact the winners afterward. All entries must be electronically postmarked by 23:59 EST on May 10, 2017, in order to be eligible. No purchase necessary. Two winners will be selected at random from all eligible entries. Good luck!

If you’d like to join Fraser and Paul Matt Sutter on their tour to Iceland in February 2018, you can find the information at astrotouring.com.

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We record the Weekly Space Hangout every Friday at 12:00 pm Pacific / 3:00 pm Eastern. You can watch us live on Universe Today, or the Universe Today YouTube page<

Catastrophic Impacts Made Life on Earth Possible

How did life on Earth originally develop from random organic compounds into living, evolving cells? It may have relied on impacts by enormous meteorites and comets — the same sort of catastrophic events that helped bring an end to the dinosaurs’ reign 65 million years ago. In fact, ancient impact craters might be precisely where life was able to develop on an otherwise hostile primordial Earth.

This is the hypothesis proposed by Sankar Chaterjee, Horn Professor of Geosciences and the curator of paleontology at the Museum of Texas Tech University.

“This is bigger than finding any dinosaur. This is what we’ve all searched for – the Holy Grail of science,” Chatterjee said.

Our planet wasn’t always the life-friendly “blue marble” that we know and love today. At one point early in its history it was anything but hospitable to life as we know it.

“When the Earth formed some 4.5 billion years ago, it was a sterile planet inhospitable to living organisms,” Chatterjee said. “It was a seething cauldron of erupting volcanoes, raining meteors and hot, noxious gasses. One billion years later, it was a placid, watery planet teeming with microbial life – the ancestors to all living things.”

Exactly how did this transition happen? That’s the Big Question in paleontology, and Chatterjee believes he may have found the answer lying within some of the world’s oldest and largest impact craters.

After studying the environments of the oldest known fossil-containing rocks in Greenland, Australia and South Africa, Chatterjee said these could be remnants of ancient craters and may be the very spots where life began in deep, dark and hot environments — similar to what’s found near thermal vents in today’s oceans.

Larger meteorites that created impact basins of about 350 miles in diameter inadvertently became the perfect crucibles, according to Chatterjee. These meteorites also punched through the Earth’s crust, creating volcanically driven geothermal vents. They also brought the basic building blocks of life that could be concentrated and polymerized in the crater basins.

In addition to new organic compounds — and, in the case of comets, considerable amounts of water — impacting bodies may also have brought the necessary lipids needed to help protect RNA and allow it to develop further.

“RNA molecules are very unstable. In vent environments, they would decompose quickly. Some catalysts, such as simple proteins, were necessary for primitive RNA to replicate and metabolize,” Chatterjee said. “Meteorites brought this fatty lipid material to early Earth.”

How organic compounds in crater basins were encapsulated in lipid membranes and became the first cells (Chatterjee)
How organic compounds in crater basins were encapsulated in lipid membranes and became the first cells (Chatterjee)

Based on research in Australia by University of California professor David Deamer, the ingredients for all-important cell membranes were delivered to Earth via meteorites and existed in water-filled craters.

“This fatty lipid material floated on top of the water surface of crater basins but moved to the bottom by convection currents,” suggests Chatterjee. “At some point in this process during the course of millions of years, this fatty membrane could have encapsulated simple RNA and proteins together like a soap bubble. The RNA and protein molecules begin interacting and communicating. Eventually RNA gave way to DNA – a much more stable compound – and with the development of the genetic code, the first cells divided.”

And the rest, as they say, is history. (Well, biology really, and no small amount of chemistry and paleontology… and some astrophysics… well you get the idea.)

Chatterjee recognizes that further experiments will be needed to help support or refute this hypothesis. He will present his findings Oct. 30 during the 125th Anniversary Annual Meeting of the Geological Society of America in Denver, Colorado.

Source: Texas Tech news article by John Davis