If there may be life within the photo voltaic system past Earth, it is likely to be discovered within the clouds of Venus. In distinction to the planet’s blisteringly inhospitable floor, Venus’ cloud layer, which extends from 30 to 40 miles above the floor, hosts milder temperatures that would help some excessive types of life.
If it’s on the market, scientists have assumed that any Venusian cloud inhabitant would look very completely different from life varieties on Earth. That’s as a result of the clouds themselves are constituted of extremely poisonous droplets of sulfuric acid — an intensely corrosive chemical that’s recognized to dissolve metals and destroy most organic molecules on Earth.
However a brand new research by MIT researchers might problem that assumption. Showing right this moment within the journal Astrobiology, the research experiences that, in actual fact, some key constructing blocks of life can persist in options of concentrated sulfuric acid.
The research’s authors have discovered that 19 amino acids which are important to life on Earth are secure for as much as 4 weeks when positioned in vials of sulfuric acid at concentrations much like these in Venus’ clouds. Particularly, they discovered that the molecular “spine” of all 19 amino acids remained intact in sulfuric acid options ranging in focus from 81 to 98 p.c.
“What is completely shocking is that concentrated sulfuric acid is just not a solvent that’s universally hostile to natural chemistry,” says research co-author Janusz Petkowski, a analysis affiliate in MIT’s Division of Earth, Atmospheric and Planetary Sciences (EAPS).
“We’re discovering that constructing blocks of life on Earth are secure in sulfuric acid, and that is very intriguing for the concept of the potential for life on Venus,” provides research writer Sara Seager, MIT’s Class of 1941 Professor of Planetary Sciences in EAPS and a professor within the departments of Physics and of Aeronautics and Astronautics. “It doesn’t imply that life there would be the similar as right here. In actual fact, we all know it may possibly’t be. However this work advances the notion that Venus’ clouds might help advanced chemical compounds wanted for all times.”
The research’s co-authors embody first writer Maxwell Seager, an undergraduate within the Division of Chemistry at Worcester Polytechnic Institute and Seager’s son, and William Bains, a analysis affiliate at MIT and a scientist at Cardiff College.
Constructing blocks in acid
The seek for life in Venus’ clouds has gained momentum lately, spurred partly by a controversial detection of phosphine — a molecule that’s thought of to be one signature of life — within the planet’s environment. Whereas that detection stays beneath debate, the information has reinvigorated an previous query: May Earth’s sister planet truly host life?
Searching for a solution, scientists are planning a number of missions to Venus, together with the primary largely privately funded mission to the planet, backed by California-based launch firm Rocket Lab. That mission, on which Seager is the science principal investigator, goals to ship a spacecraft by way of the planet’s clouds to research their chemistry for indicators of natural molecules.
Forward of the mission’s January 2025 launch, Seager and her colleagues have been testing varied molecules in concentrated sulfuric acid to see what fragments of life on Earth may also be secure in Venus’ clouds, that are estimated to be orders of magnitude extra acidic than essentially the most acidic locations on Earth.
“Folks have this notion that concentrated sulfuric acid is an especially aggressive solvent that may chop all the things to items,” Petkowski says. “However we’re discovering this isn’t essentially true.”
In actual fact, the staff has beforehand proven that advanced natural molecules equivalent to some fatty acids and nucleic acids stay surprisingly secure in sulfuric acid. The scientists are cautious to emphasise, as they do of their present paper, that “advanced natural chemistry is in fact not life, however there isn’t a life with out it.”
In different phrases, if sure molecules can persist in sulfuric acid, then maybe the extremely acidic clouds of Venus are liveable, if not essentially inhabited.
Of their new research, the staff turned their deal with amino acids — molecules that mix to make important proteins, every with their very own particular perform. Each dwelling factor on Earth requires amino acids to make proteins that in flip perform life-sustaining features, from breaking down meals to producing vitality, constructing muscle, and repairing tissue.
“When you contemplate the 4 main constructing blocks of life as nucleic acid bases, amino acids, fatty acids, and carbohydrates, we now have demonstrated that some fatty acids can type micelles and vesicles in sulfuric acid, and the nucleic acid bases are secure in sulfuric acid. Carbohydrates have been proven to be extremely reactive in sulfuric acid,” Maxwell
Seager explains. “That solely left us with amino acids because the final main constructing block to
research.”
A secure spine
The scientists started their research of sulfuric acid throughout the pandemic, finishing up their experiments in a house laboratory. Since that point, Seager and her son continued work on chemistry in concentrated sulfuric acid. In early 2023, they ordered powder samples of 20 “biogenic” amino acids — these amino acids which are important to all life on Earth. They dissolved every kind of amino acid in vials of sulfuric acid combined with water, at concentrations of 81 and 98 p.c, which characterize the vary that exists in Venus’ clouds.
The staff then let the vials incubate for a day earlier than transporting them to MIT’s Division of Chemistry Instrumentation Facility (DCIF), a shared, 24/7 laboratory that gives quite a lot of automated and handbook devices for MIT scientists to make use of. For his or her half, Seager and her staff used the lab’s nuclear magnetic resonance (NMR) spectrometer to research the construction of amino acids in sulfuric acid.
After analyzing every vial a number of occasions over 4 weeks, the scientists discovered, to their shock, that the fundamental molecular construction, or “spine” in 19 of the 20 amino acids remained secure and unchanged, even in extremely acidic situations.
“Simply displaying that this spine is secure in sulfuric acid doesn’t imply there may be life on Venus,” notes Maxwell Seager. “But when we had proven that this spine was compromised, then there could be no probability of life as we all know it.”
“Now, with the invention that many amino acids and nucleic acids are secure in 98 p.c sulfuric acid, the potential for life surviving in sulfuric acid will not be so far-fetched or implausible,” says Sanjay Limaye, a planetary scientist on the College of Wisconsin who has studied Venus for over 45 years, and who was not concerned with this research. “In fact, many obstacles lie forward, however life that advanced in water and tailored to sulfuric acid will not be simply dismissed.”
The staff acknowledges that Venus’ cloud chemistry is probably going messier than the research’s “check tube” situations. As an illustration, scientists have measured varied hint gases, along with sulfuric acid, within the planet’s clouds. As such, the staff plans to include sure hint gases in future experiments.
“There are just a few teams on this planet now which are engaged on chemistry in sulfuric acid, and they’re going to all agree that nobody has instinct,” provides Sara Seager. “I believe we’re simply extra glad than something that this newest consequence provides another ‘sure’ for the potential for life on Venus.”
