Another Key Amino Acid Found in Space: Tryptophan

Tryptophan found in the nebula IC348. Credit: Jorge Rebolo-Iglesias/NASA/Spitzer Space Telescope

Astrochemistry is the study of how molecules can form and react in space. Its roots trace back to the 1800s when astronomers such as William Wollaston and Joseph von Fraunhofer began identifying atomic elements from the spectral lines of the Sun. But it wasn’t until recent decades that the field began to mature.

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How Could We Detect Life Inside Enceladus?

Scientists recently determined that a certain strain of Earth bacteria could thrive under conditions found on Enceladus. Credit: NASA/JPL/Space Science Institute

For astrobiologists, the scientists dedicated to the search for life beyond Earth, the moons of Saturn are a virtual treasure trove of possibilities. Enceladus is especially compelling because of the active plumes of water emanating from its southern polar region. Not only are these vents thought to be connected directly to an ocean beneath the moon’s icy surface, but the Cassini mission detected traces of organic molecules and other chemicals associated with biological processes. Like Europa, Ganymede, and other “Ocean Worlds,” astrobiologists think this could indicate hydrothermal activity at the core-mantle boundary.

Both NASA and the ESA are hoping to send missions to Enceladus that could study its plumes in more detail. These include the Enceladus Orbitlander recommended in the Planetary Science and Astrobiology Decadal Survey 2023-2032 and the ESA’s Enceladus Moonraker, which could depart Earth in the next decade, taking advantage of a favorable alignment between the planets. In anticipation of what these missions could find, an international team of researchers used data from the Cassini mission to establish how samples of plume material could constrain how much biomass Enceladus has within it.

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Meteorites Bathed in Gamma Rays Produce More Amino Acids and Could Have Helped Life get Going on Earth

Carbonaceous chondrites like the Allende meteorite contain significant amounts of water and amino acids. Could they have delivered amino acids to early Earth and spurred on the development of life? Image Credit: By Shiny Things - originally posted to Flickr as AMNH - Meteorite, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=4196153

Our modern telescopes are more powerful than their predecessors, and our research is more focused than ever. We keep discovering new things about the Solar System and finding answers to long-standing questions. But one of the big questions we still don’t have an answer for is: ‘How did life on Earth begin?’

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Samples of Asteroid Ryugu Contain More Than 20 Amino Acids

Artist's impression of the Hayabusa2 spacecraft touching down on the surface of the asteroid Ryugu. Credit: JAXA/Akihiro Ikeshita?

In 2014, the Japan Aerospace Exploration Agency (JAXA) dispatched its Hayabusa2 spacecraft to rendezvous with 162173 Ryugu, a Near-Earth Asteroid (NEA) that periodically passes close to Earth. In 2018, this sample-return mission reached Ryugu and spent the next year and a half studying its surface and obtaining samples from its surface and subsurface. By 2020, these samples made it back to Earth, where scientists began analyzing them in the hopes of learning more about the early history of the Solar System and answering key questions about the origins of life.

Earlier this year, the first results of the analysis showed that Ryugu is (as expected) rich in carbon, organic molecules, and volatiles (like water) and hinted at the possibility that it was once a comet. Based on a more recent analysis, eight teams of Japanese researchers (including one from JAXA) recently announced that Ryugu carries strains of no less than 20 different amino acids -the building blocks of DNA and life itself! These findings could provide new insight into how life is distributed throughout the cosmos and could mean that it is more common than previously thought.

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One of Life’s Building Blocks can Form in Space

A new kind of chemical reaction can explain how peptides can form on the icy layers of cosmic dust grains. Those peptides could have been transported to the early Earth by meteorites, asteroids or comets. Image Credit: © S. Krasnokutski / MPIA Graphics Department

Peptides are one of the smallest biomolecules and are one of life’s critical building blocks. New research shows that they could form on the surfaces of icy grains in space. This discovery lends credence to the idea that meteoroids, asteroids, or comets could have given life on Earth a kick start by crashing into the planet and delivering biological building blocks.

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One of the Building Blocks of Life Can Form in the Harsh Environment of Deep Space Itself. No Star Required

A new study from the University of Edinburgh suggests that life could be distributed throughout the cosmos by interstellar dust. Credit: ESO/R. Fosbury (ST-ECF)

In many ways, stars are the engines of creation. Their energy drives a whole host of processes necessary for life. Scientists thought that stellar radiation is needed to create compounds like the amino acid glycine, one of the building blocks of life.

But a new study has found that glycine detected in comets formed in deep interstellar space when there was no stellar energy.

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Astronomers Report They’ve Detected the Amino Acid Glycine in the Atmosphere of Venus

The planet Venus, as imaged by the Magellan mission. Credit: NASA/JPL

Does it feel like all eyes are on Venus these days? The discovery of the potential biomarker phosphine in the planet’s upper atmosphere last month garnered a lot of attention, as it should. There’s still some uncertainty around what the phosphine discovery means, though.

Now a team of researchers claims they’ve discovered the amino acid glycine in Venus’ atmosphere.

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The Raw Materials for Amino Acids – Which are the Raw Materials for Life – Were Found in the Geysers Coming out of Enceladus

Credit: NASA/JPL-Caltech

The joint NASA/ESA Cassini-Huygens mission revealed some amazing things about Saturn and its system of moons. In the thirteen years that it spent studying the system – before it plunged into Saturn’s atmosphere on September 15th, 2017 – it delivered the most compelling evidence to date of extra-terrestrial life. And years later, scientists are still poring over the data it gathered.

For instance, a team of German scientists recently examined data gathered by the Cassini orbiter around Enceladus’ southern polar region, where plume activity regularly sends jets of icy particles into space. What they found was evidence of organic signatures that could be the building blocks for amino acids, the very thing that life is made of! This latest evidence shows that life really could exist beneath Enceladus’ icy crust.

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All Life on Earth is Made up of the Same 20 Amino Acids. Scientist Now Think They Know Why

Artist impression of the early Earth. Credit: NASA Goddard Space Flight Center Conceptual Image Lab

The question of how life on Earth first emerged is one that humans have been asking themselves since time immemorial. While scientists are relatively confident about when it happened, there has been no definitive answer as to why it did. How did amino acids, the chemical building blocks of life, come together roughly four billion years ago to create the first protein molecules?

While that question is still unanswered, scientists are making new discoveries that could help narrow it down. For instance, a team of researchers from the Georgia Institute of Technology’s Center for Chemical Evolution (CCT) recently conducted a study that showed how some of the earliest predecessors of the protein molecule may have spontaneously linked up to form a chain.

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Researchers May Have Found the Missing Piece of Evidence that Explains the Origins of Life

Structure of DNA
Deoxyribonucleic acid (DNA) is the genetic material for all known life on Earth. DNA is a biopolymer consisting of a string of subunits. The subunits consist of nucleotide base pairs containing a purine (adenine A, or guanine G) and a pyrimidine (thymine T, or cytosine C). DNA can contain nucleotide base pairs in any order without its chemical properties changing. This property is rare in biopolymers, and makes it possible for DNA to encode genetic information in the sequence of its base pairs. This stability is due to the fact that each base pair contains phosphate groups (consisting of phosphorus and oxygen atoms) on the outside with a net negative charge. These repeated negative charges make DNA a polyelectrolyte. Computational genomics researcher Steven Benner has hypothesized that alien genetic material will also be a polyelectrolyte biopolymer, and that chemical tests could therefore be devised to detect alien genetic molecules. Credit: Zephyris

The question of how life first emerged here on Earth is a mystery that continues to elude scientists. Despite everything that scientists have learned from the fossil record and geological history, it is still not known how organic life emerged from inorganic elements (a process known as abiogenesis) billions of years ago.

One of the more daunting aspects of the mystery has to do with peptides and enzymes, which fall into something of a “chicken and egg” situation. Addressing this, a team of researchers from the University College London (UCL) recently conducted a study that effectively demonstrated that peptides could have formed in conditions analogus to primordial Earth.

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