Here’s a thorny problem: What if life doesn’t always appear on planets that can support it? What if we find more and more exoplanets and determine that some of them are habitable? What if we also determine that life hasn’t appeared on them yet?
Could we send life-bringing comets to those planets and seed them with terrestrial life? And if we could do that, should we?
On Earth, all life comes down to the polymeric molecules known as deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). These two building blocks contain all of the instructions for every living organism and its many operations. In turn, these are made up of five informational components (nucleobases), which are composed of organic molecules (purines and pyrimidines). For decades, scientists have been scouring meteorite samples for these building blocks.
To date, these efforts have resulted in the detection of three of the five nucleobases within meteorites. However, a recent analysis led by researchers from Hokkaido University, Japan (with support from NASA) has revealed the remaining two nucleobases that have eluded scientists until now. This discovery could help resolve the ongoing debate about whether life on Earth emerged on its own or was assisted by organic compounds deposited by meteorites (aka. panspermia).
Researchers at Australia’s Curtin University have discovered evidence of a massive impact on the Martian surface after 4.45 billion years ago. This may not seem like a surprising revelation – after all, we know that there were several large impacts on Mars, like Hellas and Argyre, and we know that large impacts happened frequently in the early solar system – so why is this a big deal?
Can life spread throughout a galaxy like the Milky Way without technological intervention? That question is largely unanswered. A new study is taking a swing at that question by using a simulated galaxy that’s similar to the Milky Way. Then they investigated that model to see how organic compounds might move between its star systems.
A remarkable microbe named Deinococcus radiodurans (the name comes from the Greek deinos meaning terrible, kokkos meaning grain or berry, radius meaning radiation, and durare meaning surviving or withstanding) has survived a full year in the harsh environment of outer space aboard (but NOT inside) the International Space Station. This plucky prokaryote is affectionately known by fans as Conan the Bacterium, as seen in this classic 1990s NASA article.
The JAXA (Japanese Aerospace Exploration Agency) ISS moduleKib? has an unusual feature for spacecraft, a front porch! This exterior portion of the space station is fitted with robotic equipment to complete various experiments in outer space’s brutal conditions. One of these experiments was to expose cells of D. radiodurans for a year and then test the cells to see if they not only would survive but could reproduce effectively afterward. D. radiodurans proved to be up to the challenge, and what a challenge it was!
From the study of meteorite fragments that have fallen to Earth, scientists have confirmed that bacteria can not only survive the harsh conditions of space but can transport biological material between planets. Because of how common meteorite impacts were when life emerged on Earth (ca. 4 billion years ago), scientists have been pondering whether they may have delivered the necessary ingredients for life to thrive.
In a recent study, an international team led by astrobiologist Tetyana Milojevic from the University of Vienna examined a specific type of ancient bacteria that are known to thrive on extraterrestrial meteorites. By examining a meteorite that contained traces of this bacteria, the team determined that these bacteria prefer to feed on meteors – a find which could provide insight into how life emerged on Earth.
For almost two centuries, scientists have theorized that life may be distributed throughout the Universe by meteoroids, asteroids, planetoids, and other astronomical objects. This theory, known as Panspermia, is based on the idea that microorganisms and the chemical precursors of life are able to survive being transported from one star system to the next.
Expanding on this theory, a team of researchers from the Harvard Smithsonian Center for Astrophysics (CfA) conducted a study that considered whether panspermia could be possible on a galactic scale. According to the model they created, they determined that the entire Milky Way (and even other galaxies) could be exchanging the components necessary for life.