Science Archives

September 24, 2024September 24, 2024 by Evan Gough

How a Nearby Supernova Left its Mark on Earth Life

Artist's impression of a supernova. Supernovae bombarded Earth with radiation that has implications for the development of life on Earth. Image Credit: NASA

When a massive star explodes as a supernova, it does more than release an extraordinary amount of energy. Supernovae explosions are responsible for creating some of the heavy elements, including iron, which is blasted out into space by the explosion. On Earth, there are two accumulations of the iron isotope Fe60 in sea-floor sediments that scientists trace back about two or three million years ago and about five to six million years ago.

The explosions that created the iron also dosed Earth with cosmic radiation.

September 23, 2024September 23, 2024 by Evan Gough

From Frozen to Sweltering: Earth’s Climate Over the Last 485 Million Years

New research shows the global mean surface temperature across the last 485 million years. The gray shading corresponds to different confidence levels, and the black line shows the average. The colored bands along the top reflect the climate state, with cooler colors indicating icehouse (coolhouse and coldhouse) climates, warmer colors indicating greenhouse (warmhouse and hothouse) climates, and the gray representing a transitional state. Image Credit: Judd et al. 2024.

Earth’s last half-billion years were action-packed. During that time, the climate underwent many changes. There have been changes in ocean levels and ice sheets, changes in the atmosphere’s composition, changes in ocean chemistry, and ongoing biological evolution punctuated with extinction events.

A record of Earth’s temperature over the last 485 million years is helping scientists understand how it all played out and illustrating what could happen if we continue to enrich the atmosphere with carbon.

September 20, 2024September 20, 2024 by Evan Gough

Io’s Volcanoes are Windows into its Hot Interior

Juno captured this image of Io during Perijove 57. Data from Juno's JIRAM instrument is helping researchers understand how tidal heating shapes the moon's volcanic activity. Image Credit: NASA / SWRI / MSSS / Jason Perry © cc nc sa

NASA’s Juno spacecraft was sent to Jupiter to study the gas giant. But its mission was extended, giving it an opportunity to study the unique moon Io. Io is the most volcanically active body in the Solar System, with over 400 active volcanoes.

Researchers have taken advantage of Juno’s flybys of Io to study how tidal heating affects the moon.

September 19, 2024September 25, 2024 by Evan Gough

Plants Would Still Grow Well Under Alien Skies

This is an artist's illustration of the rocky super Earth HD 219134. It orbits a K-type star, a long-lived stable type of main sequence star. The light from K-type stars is different than the Sun's. Can Earth plants photosynthesize effectively near these stars? Image Credit: By NASA/JPL-Caltech - http://photojournal.jpl.nasa.gov/jpeg/PIA19833.jpg, Public Domain, https://commons.wikimedia.org/w/index.php?curid=41995148

Photosynthesis changed Earth in powerful ways. When photosynthetic organisms appeared, it led to the Great Oxygenation Event. That allowed multicellular life to evolve and resulted in the ozone layer. Life could venture onto land, protected from the Sun’s intense ultraviolet radiation.

But Earth’s photosynthetic organisms evolved under the Sun’s specific illumination. How would plants do under other stars?

September 13, 2024September 13, 2024 by Evan Gough

A Gravity Map of Mars Uncovers Subsurface Mysteries

In this new gravity map of Mars, the red circles show prominent volcanoes and the black circles show impact craters with a diameter larger than a few 100 km. A gravity high signal is located in the volcanic Tharsis Region (the red area in the center right of the image), which is surrounded by a ring of negative gravity anomaly (shown in blue). Credit: Root et al.

A team of scientists presented a new gravity map of Mars at the Europlanet Science Congress 2024. The map shows the presence of dense, large-scale structures under Mars’ long-gone ocean and that mantle processes are affecting Olympus Mons, the largest volcano in the Solar System.

September 12, 2024September 12, 2024 by Evan Gough

Groundbreaking New Maps of the Sun’s Coronal Magnetic Fields

The Daniel K. Inouye Solar Telescope has mapped the magnetic field of the Sun's corona for the first time. The corona is the source of most space weather, and this map will help scientists better understand the corona, space weather and other stars. Image Credit: Schad et al. 2024.

If you enjoyed this summer’s display of aurora borealis, thank the Sun’s corona. The corona is the Sun’s outer layer and is the source of most space weather, including aurorae. The aurora borealis are benign light shows, but not all space weather produces such harmless displays; some of it is dangerous and destructive.

In an effort to understand space weather and the solar corona, the National Science Foundation aimed the world’s most powerful solar telescope, the Daniel K. Inouye Solar Telescope, at the corona to map its magnetic fields.

September 10, 2024September 10, 2024 by Evan Gough

A Stellar Flyby Jumbled Up the Outer Solar System

This is a screenshot from a supercomputer simulation. It shows how an ancient stellar flyby shaped the Solar System. Among other things, the flyby can explain the Solar System's population of irregular moons. Image Credit: Forschungszentrum Jülich

An ancient passerby may have visited the Sun and inadvertently helped shape the Solar System into what it is today. It happened billions of years ago when a stellar drifter came to within 110 astronomical units (AU) of our Sun. The effects were long-lasting and we can see evidence of the visitor’s fleeting encounter throughout the Solar System.

September 9, 2024September 9, 2024 by Evan Gough

The True Size of Galaxies is Much Larger Than We Thought

Visualisation of the gas shroud of starburst galaxy IRAS 08339+6517. Astronomers struggle to observe this gas clearly, but new research found a way. Image Credit: Cristy Roberts ANU/ASTRO 3D

Ask most people what a galaxy is made up of, and they’ll say it’s made of stars. Our own galaxy, the Milky Way, hosts between about 100 to 300 billion stars, and we can see thousands of them with our unaided eyes. But most of a galaxy’s mass is actually gas, and the extent of the gas has been difficult to measure.

Researchers have found a way to see how far that gas extends into the cosmos.

September 5, 2024September 5, 2024 by Evan Gough

Archaeological Methods Reveal How Astronauts Work on the International Space Station

Archaeology is the study of human prehistory, so it seems incongruous to use its methods to study how humans behave in space. But that’s what astronauts aboard the International Space Station are doing.

September 3, 2024September 16, 2024 by Evan Gough

Asking the Big Question: Where Did Life Originate?

Water's Early Journey in a Solar System — Somehow, life originated on Earth. Even without knowing everything about how that happened, can we learn how likely it is to happen elsewhere? Image Credit: NASA/JPL-Caltech

Where on Earth did life originate, and where else could it occur? A comprehensive answer is most likely a long way off. But it might depend on how many suitable sites for abiogenesis there are on different worlds.