Extraterrestrial Archives

September 20, 2020September 21, 2020 by Matthew Cimone

How Much Life Would Be Required to Create the Phosphine Signal on Venus?

How can astronomers tell exo-Earths and exo-Venuses apart? Polarimetry might be the key. Image Credits: NASA

A Biosignature

Last week, an incredible announcement was made about the search for extraterrestrial life: Phosphine gas detected in the clouds of Venus – a potential indicator of life or “biosignature.” Now some gases might be a false positive for biosignatures because they can be created by other chemical processes on a planet like photochemical processes in the atmosphere or geological processes beneath the surface that create a given gas. For example, methane can also be a biosignature, and we’ve been hunting it down on Mars, but we know that methane can also be created geologically. Finding phosphine in Venusian clouds is truly remarkable because we don’t presently know of any way to create phosphine abiotically or without life being a part of the equation. Question is – how much life??

Clouds of Venus as seen from Mariner 10’s flyby – NASA

August 22, 2020February 7, 2022 by Matt Williams

Beyond “Fermi’s Paradox” VI: What is the Berserker Hypothesis?

Welcome back to our Fermi Paradox series, where we take a look at possible resolutions to Enrico Fermi’s famous question, “Where Is Everybody?” Today, we examine the possibility that the reason for the Great Silence is that all the aliens are dead!

In 1950, Italian-American physicist Enrico Fermi sat down to lunch with some of his colleagues at the Los Alamos National Laboratory, where he had worked five years prior as part of the Manhattan Project. According to various accounts, the conversation turned to aliens and the recent spate of UFOs. Into this, Fermi issued a statement that would go down in the annals of history: “Where is everybody?“

This became the basis of the Fermi Paradox, which refers to the disparity between high probability estimates for the existence of extraterrestrial intelligence (ETI) and the apparent lack of evidence. Since Fermi’s time, there have been several proposed resolutions to his question, which includes the Berserker Hypothesis. This theory suggests we haven’t heard from any alien civilizations because they’ve been wiped out by killer robots!

July 23, 2020February 7, 2022 by Matt Williams

Beyond “Fermi’s Paradox” III: What is the Great Filter?

The Karl Jansky Very Large Array at night, with the Milky Way visible in the sky. Credit: NRAO/AUI/NSF; J. Hellerman

Welcome back to our Fermi Paradox series, where we take a look at possible resolutions to Enrico Fermi’s famous question, “Where Is Everybody?” Today, we examine the possibility that there is something in the Universe that prevents life from reaching the point where we would be able to hear from it.

This became the basis of the Fermi Paradox, which refers to the high probability estimates for the existence of extraterrestrial intelligence (ETI) and the apparent lack of evidence. Seventy years later, we still haven’t answered that question, which has led to many theories as to why the “Great Silence” endures. A popular one is that there must be “Great Filter” that prevents life from reaching an advanced stage of development.

July 5, 2020July 5, 2020 by Matt Williams

Breakthrough Listen Releases its one-of-Everything “Exotica” Catalog

In July of 2015, Breakthrough Initiatives announced that it was embarking on a ten-year initiative to conduct the largest Search for Extraterrestrial Intelligence (SETI) to date. This initiative was aptly named Breakthrough Listen, which combines state-of-the-art software and data obtained by premier observatories around the world to look for signs of extraterrestrial technological activity (aka. technosignatures).

In recent years, Breakthrough Listen has made two major releases of data, and announced a lucrative collaboration with NASA’s Transitting Exoplanet Survey Satellite (TESS) mission. And most recently, Breakthrough Listen announced the release of their catalog of “Exotica” – a diverse list of objects that could be of interest to astronomers that are searching for signs of technosignatures and extraterrestrial intelligence (ETI).

June 27, 2020June 27, 2020 by Matt Williams

A Simulation of Sunsets on Other Worlds: From Venus to Titan

When we think of exploring other planets and celestial bodies, we tend to focus on the big questions. How would astronauts live there when they’re not working? What kind of strategies and technology would be needed for people to be there long term? How might the gravity, environment, and radiation effect humans who choose to make places like the Moon, Mars, and other bodies place their home? We tend to overlook the simple stuff…

For example, what will it be like to look up at the sky? How will Earth, the stars, and any moon in orbit appear? And how will it look to watch the sun go down? These are things we take for granted here on Earth and don’t really ponder much. But thanks to NASA, we now have a tool that simulates what sunsets would look like from other bodies in the Solar System – from the hellish surface of Venus to the dense atmosphere of Uranus.

June 24, 2020June 24, 2020 by Matt Williams

Calculate the Number of Alien Civilizations in the Milky Way for Yourself.

Planets everywhere. So where are all the aliens? Credit: ESO/M. Kornmesser

In recent years, the explosive nature of exoplanet discovery (over 4,164 confirmed so far!) has led to renewed interest in the timeless question: “are we alone in the Universe?” Or, as famed Italian physicist Enrico Fermi put it, “Where is everybody?” With so many planets to choose from and the rate at which our instruments and methods are improving, the search for life beyond Earth is really kicking into high gear.

At the same time, these discoveries have inspired a plethora of new studies regarding the ongoing Search for Extraterrestrial Intelligence (SETI). This includes the Alien Civilization Calculator, which is the brainchild of physicists Steven Woodling and Dominick Czernia. Inspired by recent attempts to address the statistical likelihood of advanced life in our galaxy, they offer a mathematical tool that can crunch the numbers for you!

February 20, 2020February 20, 2020 by Matt Williams

SETI Researchers Release Petabytes of Data in the Search For Aliens

Last week (Friday. Feb. 14th), the Breakthrough Listen Initiative released about 2 petabytes of optical and radio data that they have accumulated over the past four years. This is the second data release by the non-profit effort (as part of Breakthrough Initiatives) and the public is once again invited to search through the data for possible signs of extraterrestrial communications.

December 2, 2019December 2, 2019 by Matt Williams

Giant Meteor Impacts Might Have Triggered Early Earth’s Plate Tectonics

Mining asteroids might be necessary for humanity to expand into the Solar System. But what effect would asteroid mining have on the world's economy? Credit: ESA.

Plate tectonics have played a vital role in the geological evolution of our planet. In addition, many scientists believe that Earth’s geologically activity may have played an important role in the evolution of life – and could even be essential for a planet’s habitability. For this reason, scientists have long sought to determine how and when Earth’s surface changed from molten, viscous rock to a solid crust that is constantly resurfacing.

August 21, 2019August 21, 2019 by Matt Williams

Earth is an Exoplanet to Aliens. This is What They’d See

Reconstruction of what Earth's light curve would look like. Credit: S. Fan et. al., arXiv (2019) arXiv:1908.04350

The study of exoplanets has matured considerably in the last ten years. During this time, the majority of the over 4000 exoplanets that are currently known to us were discovered. It was also during this time that the process has started to shift from the process of discovery to characterization. What’s more, next-generation instruments will allow for studies that will reveal a great deal about the surfaces and atmospheres of exoplanets.

This naturally raises the question: what would a sufficiently-advanced species see if they were studying our planet? Using multi-wavelength data of Earth, a team of Caltech scientists was able to construct a map of what Earth would look like to distant alien observers. Aside from addressing the itch of curiosity, this study could also help astronomers reconstruct the surface features of “Earth-like” exoplanets in the future.

August 21, 2019August 23, 2019 by Matt Williams

AI Could Help the Europa Clipper Mission Make New Discoveries!

Artist's concept of a Europa Clipper mission. Credit: NASA/JPL

In 2023, NASA plans to launch the Europa Clipper mission, a robotic explorer that will study Jupiter’s enigmatic moon Europa. The purpose of this mission is to explore Europa’s ice shell and interior to learn more about the moon’s composition, geology, and interactions between the surface and subsurface. Most of all, the purpose of this mission is to shed light on whether or not life could exist within Europa’s interior ocean.

This presents numerous challenges, many of which arise from the fact that the Europa Clipper will be very far from Earth when it conducts its science operations. To address this, a team of researchers from NASA’s Jet Propulsion Laboratory (JPL) and Arizona State University (ASU) designed a series of machine-learning algorithms that will allow the mission to explore Europa with a degree of autonom.