DNA – astroengine.com

Our Universe Is a Cosmic Mixologist Looking for the Recipe of Life

Creating the conditions of interstellar space in the lab has led to a sweet discovery

The Egg Nebula, as imaged by Hubble, is a protoplanetary nebula with a young star in its core [NASA/ESA]

What do you get if you combine water with methanol and then bombard the mix with radiation? It turns out that the resulting cocktail is where the building blocks for life are found. But these chemicals aren’t bubbling out of the puddles of primordial goo pooling on some alien planet; the cocktail shaker is the frigid depths of interstellar space and the mixologist is the universe.

As described in a new study published on Tuesday in Nature Communications, a team of NASA scientists took what they knew of interstellar space and recreated it in a laboratory experiment. Interstellar space may not seem like a place where the chemistry of life could gain a foothold, but given enough time and the right ingredients, chemical reactions do happen — albeit very slowly. And if there’s one thing the universe has it’s time, and we’re beginning to understand that the cosmos we reside in could be a vast organic experiment.

“The universe is an organic chemist,” said Scott Sandford, a senior scientist in the NASA Ames Astrophysics and Astrochemistry Laboratory and co-investigator of the study. “It has big beakers and lots of time — and the result is a lot of organic material, some of which is useful to life.”

To see what chemistry might be going on in the void between the stars, the researchers simulated this extreme environment inside a vacuum chamber at Ames that was cooled to near-absolute zero. Inside, they placed an aluminum substance and then added the gaseous mixture of water vapor and methanol, a very common carbon-based molecule that is known to exist throughout our galaxy. Holding the aluminum at such low temperatures caused a frosty layer to form upon it. Then, they irradiated the substance with ultraviolet light — a form of radiation that is abundant in stellar nurseries, for example — and found that some interesting chemical reactions had occurred.

They discovered that a variety of sugar derivatives had formed on the substance — and one of those sugars was 2-deoxyribose. Yes, the same stuff you’d find in deoxyribonucleic acid. That’s the “D” in our DNA.

But this isn’t the first time an essential ingredient for life has been created in the lab while simulating the conditions of interstellar space. In 2009, the same team announced the discovery of uracil in their laboratory experiments — a key component of ribonucleic acid (RNA), which is central to protein synthesis in living systems. Also, in 2016, a French group discovered the formation of ribose, the sugar found in RNA.

“For more than two decades we’ve asked ourselves if the chemistry we find in space can make the kinds of compounds essential to life. So far, we haven’t picked a single broad set of molecules that can’t be produced,” said Sandford in a NASA statement.

Although these are significant discoveries that provide new insights to how and where the most basic ingredients for life may form, it’s a long way from helping us understand whether or not life is common throughout the universe. But it turns out that some of the coldest spaces in the cosmos could also be the most fertile environments for the formation of a range of chemicals that are essential for life on Earth. It’s not such a reach, then, to realize that the protoplanetary disks surrounding young stars will also contain these chemicals and, as planets form, these chemicals become an intrinsic ingredient in young planets, asteroids and comets. Over four billion years ago, when the planets condensed from our baby Sun’s nebulous surroundings, Earth may have formed with just the right abundance of molecules that form the backbone of DNA and RNA to kick-start the genesis of life on our planet. Or those ingredients were delivered here later in the frozen cores of ancient comets and asteroids.

The building blocks of life are probably everywhere, but what “spark” binds these chemicals in such a way that allows life to evolve? This question is probably well beyond our understanding for now, but it seems that if you give our Cosmic Mixologist enough time to concoct all the chemicals for life, life will eventually emerge from the cocktail.

The Ultimate Paternity Test: Are We Martian?

war-of-the-worlds — "Dad?" A scene from *War of the Worlds*.

This rather outlandish, sci-fi notion comes straight from the fertile minds of researchers from MIT, the Massachusetts General Hospital and Harvard University who are proposing a biology experiment that could be sent on a future Mars surface mission. If their hypothesis is proven, we wouldn’t only have an answer for the age old question: Are we alone? but we’d also have an answer for the not-so-age-old question: Did life from Mars spawn life on Earth?

The idea goes like this: countless tons of material from Mars has landed on Earth. We know this to be true; meteorites have been discovered on Earth that originate from the Red Planet. These rocks were blasted from the Martian surface after eons of asteroid impacts, and the rocks then drifted to Earth.

If there was once life on Mars — a concept that isn’t that far-fetched, considering Mars used to boast liquid water in abundance on its surface — then perhaps some tiny organisms (not dislike the hardy cyanobacteria that is thought to have been one of the earliest forms of life to evolve on our planet) hitched a ride on these rocks. If some of these organisms survived the harsh conditions during transit from Mars to Earth and made it though the searing heat as the meteorite fell through our atmosphere, then perhaps (perhaps!) that is what sparked life on Earth.

You may have heard a few variations of this mechanism, it is of course the “panspermia” hypothesis. Panspermia assumes that life isn’t exclusive to just one rocky body like Earth, perhaps life has the ability to hop from one planet to the next, helped on its way by asteroid impacts. Not only that, but perhaps (perhaps!) tiny microorganisms could drift, encased in interstellar dust, akin to pollen drifting in the wind, seeding distant star systems.

Naturally, when considering the distance between the planets (let alone the light-years between the stars!), one might be a little skeptical of panspermia. But it certainly would help us understand how life first appeared on Earth. After all, it’s not as if the solar system has a natural quarantine system in place — if Mars had (or has) bacteria on its surface, perhaps they have been spread to Earth, like an interplanetary flu bug. Also, as experiments are showing us, microorganisms have an uncanny ability to survive in space for extended periods of time.

So, according to my esteemed Discovery News colleague Ray Villard, the MIT team led by Christopher Carr and Maria Zuber and Gary Ruvkun, a molecular biologist at the Massachusetts General Hospital and Harvard University, are proposing to build an instrument to send to Mars. But this instrument won’t be looking for signs of life, it will be testing the hypothetical Martian DNA and RNA. Should this interplanetary paternity test prove positive, proving a relationship between Earth Brand™ Life and Mars Brand™ Life, then this could be proof of some extraterrestrial cross-pollination.

Although this is complete conjecture at this time, as there is no proof that life has ever existed on Mars (despite what research in dodgy research journals tell us), it is certainly an interesting idea that would not only test the hypothesis of panspermia, but also give us a clue about the potential human colonization of Mars.

To quote Ray:

This could give us pause about sending humans to a germ-laden alien world. It would be an ironic twist on the H.G. Wells classic 1898 novel “The War of the Worlds,” where invading Martians succumb to the common cold from Earth microbes.

See, Wells’ Martian warriors should have done genome testing first.

Could Extraterrestrial Genes Be Like Ours?

DNA and amino acids. Not just a terrestrial thing? (©CG4TV)

This is probably one of the biggest questions that hang over science fiction story lines: Will extraterrestrials have any resemblance to Life As We Know It™? To be honest, to toy with the thought of anything other than carbon-based life is pure conjecture, just because there might be some other form of life (such as silicon-based creatures), doesn’t mean there is (doesn’t mean there isn’t, either). So, here we are with the only form of life we know and understand, carbon-based life that was somehow spawned via a crazy mix of amino acids and some astronomical or terrestrial event that sparked the formation of prokaryotes (a.k.a. the simplest single-celled speck of life) some 4 billion years ago.

So we have an understanding of what formed life on Earth, perhaps if we look for the traces of evidence that evolved into Life As We Know It™ we can gauge whether extraterrestrial life has-formed/is-forming/will-form elsewhere in the observable Universe. From simulations of Earth evolution, scientists have predicted that 10 types of amino acids should form with the planet. These 10 amino acids are found inside the proteins of all living things on Earth. The same 10 amino acids have been found inside meteorites. Therefore, we already have a connection with the amino acids we find here on Earth and amino acids found in chunks of rock from elsewhere in the Solar System.

Now, a group of Canadian researchers have found that the same 10 amino acids are readily available elsewhere in the cosmos. Does this mean the components for life are common, not only on Earth, in the Solar System, but also in the Milky Way (and beyond)? It looks like it…
Continue reading “Could Extraterrestrial Genes Be Like Ours?”