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The Arrokoth space rock shaped like a snowman may have sparked life on Earth

Jack Austin, February 16, 2020 2:05PM

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An artist's illustration obtained from NASA showing the New Horizons spacecraft encountering the space “snowman. Picture: HO / NASA/JHUAPL/SwRI / AFP) media_cameraAn artist's illustration obtained from NASA showing the New Horizons spacecraft encountering the space “snowman. Picture: HO / NASA/JHUAPL/SwRI / AFP)


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A distant space rock shaped like a snowman that formed 4.6 billion years ago may have sparked life on Earth.

The peanut-like object named Arrokoth is the most distant object humans have ever explored, at 6.5 billion kilometres from our home planet.

Arrokoth, previously named Ultima Thule, was pictured early last year by NASA’s New Horizons spacecraft.

Images of the “snowman” released in January 2019 wowed the world – and space scientists have been investigating the data* ever since.

media_cameraArrokoth, the farthest, most primitive object in the solar system. Picture: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Roman Tkachenko via AP)

The rock sits in the Kuiper Belt, a mysterious region of our solar system beyond the eight major planets.

And now scientists have detailed the object’s true nature and history in three separate studies.

“Arrokoth is the most distant, most primitive* and most pristine* object ever explored by spacecraft,” said Alan Stern, who works on the New Horizons project.

“We believe the result marks a significant advance in understanding overall planetesimal* and planet formation.”

Arrokoth is now believed to have been two separate objects that eventually joined into a single entity*.

They were likely created by an ancient planetary collision billions of years ago, and gently came together due to their gravitational* pulls.

The “space snowman” is about 35km long and 19km wide, and marked with several craters.

The space rock is also very cold, and is covered with methanol* ice.

New Horizons Ultima Thule Flyby media_cameraNew Horizons principal investigator Alan Stern. Picture: NASA/Joel Kowsky / AFP

Importantly, it has an obvious reddish colour – which could link it to the presence of life on Earth.

Scientists think that it’s likely because of evidence of organic molecules* on Arrokoth. Organic molecules are carbon-based. And carbon is a primary component of all known life on Earth.

“That these complex organics are so ubiquitous* in colder parts of the universe means they are readily available to lead to formation of life,” said Dr Will Grundy, of the University of Arizona, speaking to London’s The Telegraph newspaper.

Dr Grundy, who has been analysing the New Horizons data, said: “Objects like Arrokoth certainly could have delivered them to early Earth from the far edge of the solar system, but that’s not the only possible source.”

NASA releases clearest image yet of 'snowman' space rock

New Horizons is now millions of kilometres beyond Arrokoth.

During its fly-by on January 1, it spent several hours collecting data which scientists will study over the next 20 months.

The spacecraft will continue downloading images and other data in the days and months ahead.

The latest research on Arrokoth was published in the journal Science.


  • data: facts and statistics collected together for reference or analysis
  • primitive: ancient
  • pristine: unspoilt or in good condition
  • planetesimal: a body which could come together with many others under gravitation to form a planet.
  • entity: a being
  • gravitational: relating to movement towards a centre of gravity
  • methanol: a toxic, colourless, volatile flammable liquid alcohol
  • organic molecules: a molecule of the kind normally found in living systems.
  • ubiquitous: common or found everywhere


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  1. What is the name of the space “snowman”
  2. How do scientists think it formed?
  3. How far is it from Earth?
  4. Why is its red colour important?
  5. When did New Horizons do its fly-by?


1. Facts, theories, wonderings
Space exploration like that of NASA’s New Horizon spacecraft can help humans find out new information, form theories and ponder new questions.

Create a table with three headings — Facts, Theories and Wonderings.

  • Under the Facts heading record three things that have been found out about Arrokoth that are definitely true.
  • Under the Theories heading write down three things that researchers believe could be true.
  • Under the Wonderings heading record three questions that the article has raised for you.

Time: allow 30 minutes to complete this activity
Curriculum Links: English; Science

2. Extension
Create a mini picture glossary containing six space-related nouns you can find in the article. Write each noun and draw a picture of the object.

Time: allow 15 minutes to complete this activity
Curriculum Links: English; Science

After reading the article, with a partner, highlight as many wow words or ambitious pieces of vocabulary that you can find in yellow. Discuss the meanings of these words and see if you can use them orally in another sentence.

HAVE YOUR SAY: Do you believe a space rock such as Arrokoth could have delivered life to Earth?
No one-word answers. Use full sentences to explain your thinking. No comments will show until approved by editors.

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