David Bowie might have asked if there was life on Mars, but scientists now think life may have started on a very different red world.
Experts in France and the United States say that a snowman-shaped space rock called Arrokoth, on the outskirts of our solar system beyond Pluto, is covered in sugars.
These include glucose and ribose, sugars that are “building blocks” of RNA, the molecule found in the cells of humans and most life forms on Earth.
At 4 billion miles away from the sun, Arrokoth is “too cold to support life as we know it,” NASA says.
But the new findings suggest that smaller comets could have transported sugar molecules necessary for the origin of life from Arrokoth to the early Earth, about 4.5 billion years ago.
Arrokoth is a strange red, snowman-shaped rock found in our solar system, about 4 billion miles away from the sun. Pictured is Arrokoth in a 2019 snapshot from NASA’s New Horizons spacecraft.
Researchers say Arrokoth is rich in glucose and ribose, which are fundamental components of RNA (a nucleic acid present in all living cells).
The team of experts, led by Dr. Cornelia Meinert of the CNRS-Côte d’Azur University in France, believes that cosmic rays transform methanol ices into sugars in Arrokoth, giving it its red color.
Arrokoth is not a planet but a “planetesimal”, meaning it is a very early remnant of the solar system left over from the formation of the planets.
It consists of two bodies, 21 and 14 kilometers in diameter, that probably orbited each other before coming together billions of years ago.
Orbiting in the distant Kuiper Belt and 3.93 billion miles (6.33 billion kilometers) from Earth, it is the most distant object ever visited by a spacecraft.
In 2019, the New Horizons spacecraft completed a flyby of Arrokoth revealing its unusual shape and striking red hue.
But it remains a mystery why Arrokoth, which means “sky” in the Native American Powhatan or Algonquian language, turned so red.
Arrokoth’s surface is covered in a layer of frozen methanol, the type of alcohol that blinds humans, as well as organic compounds responsible for its red color.
One theory proposed that at very low temperatures, methanol could be converted into these red compounds under the radiation of “galactic cosmic rays,” high-energy particles that bombard the solar system.
In 2019, Arrokoth became the most distant object visited by a spacecraft when New Horizons passed by this distant object.
To test this theory, the researchers cooled samples of frozen methanol to -233°C (40 Kelvin) with electrons to simulate 1.8 billion years of Arrokoth’s exposure to galactic cosmic rays.
Not only did they find that this process produced a red color extremely similar to that of Arrokoth, but it also produced a “complex set” of “biologically significant” sugars.
However, Dr Meinert told MailOnline that this does not mean that Arrokoth had been transformed into a delicious delicacy.
Dr Meinert says: ‘We detected glucose and galactose in those samples that are known to trigger the sweet taste.
“Given the low abundance of these individual sugars and especially other organic molecules that are considered toxic in these ices, I definitely would not lick those ices.”
Gastronomic importance aside, this discovery could be vital to understanding how life could arise in the solar system.
The sugars found in Arrokoth are the same simple organic compounds that make up RNA, a DNA-like molecule found in all living cells.
Although these are organic compounds, that does not mean that Arrokoth, or similar rocks, are home to any form of life.
Instead, billions of years ago the sugars from Arrokoth could have been transferred via comets to the inner solar system, acting as one of the many ingredients needed for life to form.
Researchers suggest that a “sugar world” like Arrokoth could have been pulled from the Kuiper Belt and collided with our planet billions of years ago.
This discovery makes an object like Arrokoth a strong candidate for the origins of the molecules that started life on Earth.
Although Arrokoth (pictured) is rich in organic molecules and is believed to contain ice in its core, it is not likely to host any form of life.
However, Dr. Meinert explains: “The simple building blocks of life do not automatically lead to living cells.
“Evolution is required to assemble simple molecules into functional polymers.”
Although studies suggest that the planetesimal could contain ancient ice in its core, it is too cold for the formation of liquid water.
Arrokoth and other planetesimals are remnants of the formation of planets 4.5 billion years ago and are found in the Kuiper belt, which is home to comets.
In his article, published in proceedings of the National Academy of SciencesThe researchers write that this could have “brought biologically important molecules, such as carbohydrates, to the early Earth.”
Studies have even shown that comets slowed by the gravity of other planets could keep biological molecules safe in the event of a fierce collision with Earth.
That could mean that the origins of life as we know it could have begun with a sugary red rock in the icy reaches of space.
WHAT IS ARROKOTH?
Ultima Thule, now known as Arrakoth, was originally thought to be two separate objects.
The Kuiper Belt object was discovered by the Hubble Space Telescope in 2014. Officially known as 2014 MU69, it was nicknamed Ultima Thule in an online vote.
In classical and medieval literature, Thule was the farthest and northernmost place beyond the known world.
In November 2019 it was formally renamed Arrakoth to avoid unwanted connections with the Nazi regime.
Arrokoth means “heaven” in the Powhatan and Algonquian languages.
The Nazi party used the phrase ‘Ultima thule’ to refer to the mythical homeland of the Aryan people.
When New Horizons first glimpsed the rocky ice ball in August, it was just a dot.
NASA’s New Horizons passed by the object on January 1, 2019, 4.1 billion miles from Earth.
In 2019, an ongoing investigation into data sent back from New Horizons revealed that it was not two items, but a single snowman-like object.
In 2019, an ongoing investigation into the data sent from New Horizons revealed that it was not two elements, but a single connected element.
High-resolution images revealed that it had a “snowman” appearance.
It is now the most distant, most primitive and most pristine object ever explored by a spacecraft.
It is now known to be about the size of Seattle, at 22 miles long and 12 miles wide.
It also has a uniformly reddish, smooth and wavy surface with few craters.
It has now been officially classified as planetesimals, objects that were among the original building blocks of the solar system.