Name: When Earth Was Bombarded by Asteroids
Uploaded: undefined
Duration: undefined

NOVA

Four and a half billion years ago, Earth was battered by relentless asteroid impacts powerful enough to vaporize oceans and melt its crust. Despite the chaos, life emerged anyway.

What studying the surface of the Moon revealed about Earth’s apocalyptic youth.

When Earth Was Bombarded by Asteroids

Carlisle Companies

Viking

NOVA Science Trust Logo

Four and a half billion years ago, Earth was battered by relentless asteroid impacts powerful enough to vaporize oceans and melt its crust. Despite the chaos, life emerged anyway.

What studying the surface of the Moon revealed about Earth’s apocalyptic youth.

Planet Earth

When Earth Was Bombarded by AsteroidsPublished: January 30, 2025NARRATOR: Craters are a reminder of our solar system's formation around 4.56 billion years ago. It began as a disc of dust and gas in orbit around the young sun. The solid materials collided and clumped together to gradually form the rocky planets.SIMONE MARCHI: As a result of the formation of the earth, there were still lots of debris and asteroids and other smaller objects flying around the sun. Those objects kept colliding with the surface of the earth.NARRATOR: About four and a half billion years ago, a single object the size of Mars or even bigger may have crashed into the young earth. This high resolution simulation reveals how the collision flung enough molten and vaporized debris into space to create the moon.SIMONE MARCHI: I'm trying to understand the early evolution of the earth and the effects of all those impacts that were taking place during the idea on the earth. So we do this by building models.NARRATOR: One of the most important sources of data comes from NASA's lunar reconnaissance mission. This robotic spacecraft has made a 3D map of the moon's surface at extremely high resolution.SIMONE MARCHI: The first thing that we do is to look at the surface of the moon. It is much older than the surface of the earth. The surface of the moon is full of impact graters, all the impact graters, and so we can use that information by mapping how many there are and their sizes and their ages, and that will provide us the primary information that we need to build our models.NARRATOR: It took an international team decades to collect the data. But they finally created a computer model that took what happened on the moon during the Hadean and simulated the asteroids that would've hit the earth during the same stretch of time.SIMONE MARCHI: And the outcome of that, our first modeling was staggering. We are seeing the entire surface of the earth that is strongly affected by impact. Every single circle that you see here is an impact, is a collision.The prediction was that there were a tremendous number of impacts, even large one. Imagine an object the size of the moon that could have collided with the earth. That would have basically wiped out almost entirely perhaps the oceans, vaporized the oceans and melted a large portion of the crust of the earth.NARRATOR: This series of apocalyptic bombardments might look like it created a chaotic hellscape on earth. Even during asteroid impacts, there must have been enough habitable conditions somewhere on the planet for life to get a foothold.

United States

Northern Mariana Islands

Puerto Rico

American Samoa

Guam

U.S. Virgin Islands

U.S. Minor Outlying Islands

US & Territories

Colossal explosions shake a remote corner of the Siberian tundra, leaving behind massive craters. In Alaska, a huge lake erupts with bubbles of inflammable gas. Scientists are discovering that these mystifying phenomena add up to a ticking time bomb, as long-frozen permafrost melts and releases vast amounts of methane, a potent greenhouse gas. What are the implications of these dramatic developments in the Arctic? Scientists and local communities alike are struggling to grasp the scale of the methane threat and what it means for our climate future. (Premiered February 2, 2022)

In the Arctic, enormous releases of methane, a potent greenhouse gas, threaten the climate.

Arctic Sinkholes

The top half of Jupiter in blue and green against a night sky

A composite image of Jupiter using images captured by the James Webb Space Telescope. Image Credit: NASA, ESA, CSA, Jupiter ERS Team; image processing by Judy Schmidt.

Explore the cosmos, delve into ancient history, and follow an extreme rescue with NOVA’s most-watched documentaries released in 2022.

NOVA’s most popular science documentaries of 2022

Four bright orange loops brand off of a dark blue blob

A transmission electron micrograph of HIV-1 virus particles (orange) replicating from the plasma membrane of an infected H9 T cell. Credit: NIAID, Flickr

Scientists have cured a handful of people of HIV by piggybacking on treatments they received for blood cancer. But does that bring a widespread cure any closer?

When Earth Was Bombarded by Asteroids

Support Provided By

Explore More

Asteroids: Spark of Life?

Ancient Earth

Building Blocks of Life Discovered on Distant Asteroid

Transcript

Credits

Support Provided By

Explore More

Asteroids: Spark of Life?

Ancient Earth

Building Blocks of Life Discovered on Distant Asteroid