Earth has had a long and complex history since its formation roughly 4.5 billion years ago. Initially, it was a molten ball, but eventually, it cooled and became differentiated. The Moon formed from a collision between Earth and a protoplanet named Theia (probably), the oceans formed, and at some point in time, about 4 billion years ago, simple life appeared.
Those are the broad strokes, and scientists have worked hard to fill in a detailed timeline of Earth’s history. But there are a host of significant and poorly-understood periods in the timeline, lined up like targets for the scientific method. One of them concerns UV radiation and its effects on early life.
A new study probes the effects of UV radiation on Earth’s early life-forms and how it might have shaped our world.
Continue reading “The Early Earth was Really Horrible for Life”
A lot has to go right for a planet to support life. Some of the circumstances that allow life to bloom on any given planet stem from the planet’s initial formation. Here on Earth, circumstances meant Earth’s crust contains about 5% iron by weight.
A new paper looks at how Earth’s iron diminished over time and how that shaped the development of complex life here on Earth. Is iron necessary for complex life to develop on other worlds?
Continue reading “Life on Earth Needed Iron. Will it be the Same on Other Worlds?”
If NASA and other space agencies don’t want us to freak out about asteroids colliding with Earth, why do they give them names like Apophis? It sounds apocalyptic.
Apophis was the ancient Egyptian god of Chaos. He was an evil serpent that dwelled in endless darkness, the enemy of light and truth. So when they informed us that an asteroid named Apophis was due for a close encounter with Earth in 2029, people were understandably anxious. After all, Earth’s previous dominant inhabitants were evicted by an asteroid.
Continue reading “Asteroid Apophis’ 2029 Flyby Will Provide a Bonanza of Asteroid Science”
Where did Earth’s water come from? Comets may have brought some of it. Asteroids may have brought some. Icy planetesimals may have played a role by crashing into the young Earth and depositing their water. Hydrogen from inside the Earth may have contributed, too. Another hypothesis states the collision that formed the Moon gave Earth its water.
There’s evidence to back up all of these hypotheses.
But new research suggests that the Sun and its Solar Wind may have helped delivered some water, too.
Continue reading “Did the Earth’s Water Come From the Sun?”
Without phosphorus, there’s no life. It’s a necessary part of DNA, RNA, and other biological molecules like ATP, which helps cells transport energy. But any phosphorus that was present when Earth formed would’ve been sequestered in the center of the molten planet.
So where did phosphorus come from?
It might have come from cosmic dust.
Continue reading “Did Cosmic Dust Deliver the Phosphorus Needed for Life?”
It’s one of nature’s topsy-turvy tricks that the deep interior of the Earth is as hot as the Sun’s surface. The sphere of iron that resides there is also under extreme pressure: about 360 million times more pressure than we experience on the Earth’s surface. But how can scientists study what happens to the iron at the center of the Earth when it’s largely unobservable?
With a pair of lasers.
Continue reading “There’s So Much Pressure at the Earth’s Core, it Makes Iron Behave in a Strange Way”
Planets without plate tectonics are unlikely to be habitable. But currently, we’ve never seen the surface of an exoplanet to determine if plate tectonics are active. Scientists piece together their likely surface structures from other evidence. Is there a way to determine what exoplanets might be eggshells, and eliminate them as potentially habitable?
The authors of a newly-published paper say there is.
Continue reading “Eggshell Planets Have a Thin Brittle Crust and No Mountains or Tectonics”
The latest satellite in the Landsat family of Earth observation spacecraft has collected its “first light” images of our planet. Landsat 9 launched on September 27, 2021 and it continues the nearly 50-year tradition of making critical observations to help with energy and water management, forest monitoring, human and environmental health, urban planning, disaster recovery and agriculture.
Continue reading “Landsat 9’s First Images are Here”
Science fiction author Frank Herbert is renowned for the richly-detailed worlds he created. None of his work is more well-known than “Dune,” which took him six years to complete. Like his other work, Dune is full of detail, including the description of planet Dune, or as the Fremen call it, Arrakis.
Dune is an unforgiving desert world that suffers powerful dust storms and has no rainfall. Scientists who specialize in modelling climates set out to see how realistic Dune is compared to exoplanets. Their conclusion?
Frank Herbert did a great job, considering he created Dune in the 1960s.
Continue reading “Scientists Simulate the Climate of Arrakis. It Turns Out Dune is a Pretty Realistic Exoplanet”
Auroral activity on Earth varies over time. As the magnetic poles drift, auroras can appear at different latitudes around the globe. Solar activity also affects them, with powerful solar storms pushing the auroras further into mid-latitudes.
In an effort to better understand how auroras move around, how they’ll move in the future, and when powerful solar storms might pose a threat, a team of researchers have tracked auroral activity for the last 3,000 years.
Continue reading “Researchers Use Ancient Literature to Track 3,000 Years of Auroras”