Ancient Earth Archives

January 31, 2024January 31, 2024 by Laurence Tognetti

How Did Life Get Started on Earth? Atmospheric Haze Might Have Been the Key

Color-composite of Titan made from raw images acquired by Cassini on April 7, 2014. (NASA/JPL-Caltech/SSI/J. Major)

A recent study accepted to The Planetary Science Journal investigates how the organic hazes that existed on Earth between the planet’s initial formation and 500 million years afterwards, also known as Hadean geologic eon, could have contained the necessary building blocks for life, including nucleobases and amino acids. This study holds the potential to not only help scientists better understand the conditions on an early Earth, but also if these same conditions on Saturn’s largest moon, Titan, could produce the building blocks of life, as well.

November 14, 2023November 14, 2023 by Evan Gough

Earth’s Past and Future Habitability Depends on Our Protection from Space Weather

Sun with a huge coronal mass ejection. Image credit: NASA

A bewildering number of factors and variables led up to the planet we occupy today, where life finds a way to survive and even thrive in the most marginal conditions. The Sun is the catalyst for it all, propelling life on its journey to greater complexity with its steady fusion.

But the Sun is only benign because of Earth’s built-in protection, the magnetosphere. Both the Sun and the magnetosphere have changed over time, with each one’s strength ebbing and flowing. The Sun drives powerful space weather our way, and the magnetosphere shields the Earth.

How have these two phenomena shaped Earth’s habitability?

August 4, 2020August 4, 2020 by Evan Gough

Microbes Were Dormant for Over 100 Million Years, But They Were Able to Spring Back to Life

Magnified image showing microbes revived from 101.5-million-year-old sediment. Image Credit:Japan Agency for Marine-Earth Science and Technology

At the bottom of the ocean in the South Pacific Gyre, there’s a sediment layer that is among the most nutrient-starved environments on Earth. Because of conditions in that area, there’s almost no “marine snow”—the shower of organic debris common in the ocean—that falls to the ocean floor. Without all that organic debris falling to the floor, there’s a severe lack of nutrients there, and that makes this one of the least hospitable places on Earth.

A team of researchers took sediment samples from that area, and extracted 101.5 million year old microbes. When they “fed” those microbes, they sprang back to life.

The results are expanding our knowledge of microbial life and how long it can be dormant when conditions force it to be.

July 24, 2020July 24, 2020 by Evan Gough

What Cracked the Earth’s Outer Shell and Started its Plate Tectonics?

A snapshot of a model from the new work, showing the late stages of growth and coalescence of a new global fracture network. Fractures are in black / shadow, and colors show stresses (pink color denotes tensile stress, blue color denotes compressive stress). Image Credit: Tang et al, 2020.

Earth’s lithosphere is made up of seven large tectonic plates and a number of smaller ones. The theory of plate tectonics that describes how these plates move is about 50 years old. But there’s never really been an understanding of how this system developed, and how the Earth’s shell split into separate plates and started moving.

Now a group of researchers have a possible explanation.

June 15, 2020June 15, 2020 by Evan Gough

Space Dust Delivered Water to Vesta, Could it Have Done the Same for Earth?

An artful image of dwarf planet Vesta, with an image of micrometeorite overlaid. Image Credit: Ogliore Lab

One of the most enduring questions about Earth regards the origins of its water. Where did it come from? One widely-held theory gives comets the honor of bringing water to Earth. Another one says that Earth’s water came when a protoplanet crashed into early Earth, not only delivering a vast quantity of water, but creating the Moon.

Now a new study shows that the minor planet Vesta got its water from space dust. Could that help explain the origin of Earth’s water?

March 3, 2020March 3, 2020 by Evan Gough

3 Billion Years Ago, the World Might Have Been a Waterworld, With No Continents At All

Artist's depiction of a waterworld. A new study suggests that Earth is in a minority when it comes to planets, and that most habitable planets may be greater than 90% ocean. Credit: David A. Aguilar (CfA)

Evidence from an ancient section of the Earth’s crust suggest that Earth was once a water-world, some three billion years ago. If true, it’ll mean scientists need to reconsider some thinking around exoplanets and habitability. They’ll also need to reconsider their understanding of how life began on our planet.