Space and astronomy news
The origin of Earth’s water has been an enduring mystery. There are different hypotheses and theories explaining how the water got here, and lots of evidence supporting them.
But water is ubiquitous in protoplanetary disks, and water’s origin may not be so mysterious after all.
Continue reading “Earth’s Water is 4.5 Billion Years Old”
Can we build an enormous umbrella to dim the Sun? Such a feat would be a megaproject on a scale like no other. It would take at least 400 dedicated rocket launches a year, for ten years (There have been 172 rocket launches by all nations so far in 2022). The project would weigh in at 550,000 tons: at its lightest. And it would be an ecological experiment that puts us all – the entire planet – in the petri dish, with high risk and high reward. But could such a project actually reverse climate change and bring us back from the brink of global disaster?
The answer seems to be yes, it could work. But there are consequences, and with the planet at stake, it seems wise to examine them before committing to such a thing.
Continue reading “To Fight Climate Change, We Could Block the Sun. A Lightweight Solar Sail Could Make it Feasible”
There are 8 billion of us now. The UN says when the population peaks around the year 2100, there’ll be 11 billion human souls. Our population growth is colliding with the natural world on a greater scale than ever, and we’re losing between 200 and 2,000 species each year, according to the World Wildlife Federation.
An Engineer from the UK says that one way to mitigate the damage from the clash between humanity and nature is to create more habitat. We could do that by building Terran ecosystem preserves on Mars.
Continue reading “Should We Build a Nature Reserve on Mars?”
Have you ever seen a lunar eclipse of the Earth from the far side of the Moon? Now we have.
On Monday (November 28, 2022) NASA’s Orion spacecraft streamed back live video showing the Earth and Moon right next to each other, followed by a stunning view of the Moon eclipsing the Earth.
What a time to be alive! Image editor Kevin Gill might have said it best:
Continue reading “OK, Artemis. Now You’re Just Showing Off. A Stunning View of the Moon Eclipsing Earth From the Orion Spacecraft”
Earth is about 29% land and 71% oceans. How significant is that mix for habitability? What does it tell us about exoplanet habitability?
Continue reading “What’s the Best Mix of Oceans to Land for a Habitable Planet?”
Is there anything good about volcanoes? They can be violent, dangerous, and unpredictable. For modern humans, volcanoes are mostly an inconvenience, sometimes an intriguing visual display, and occasionally deadly.
But when there’s enough of them, and when they’re powerful and prolonged, they can kill the planet that hosts them.
Continue reading “Volcanoes are the worst. They’ve caused extinctions on Earth, and probably killed Venus”
Earth is a strange world. A warm, rocky planet covered with oceans of liquid water. This strangeness is central to life on Earth, but it has been a longstanding puzzle for astronomers. Just why is our planet wet while other terrestrial worlds are dry? Where did all of Earth’s water come from?
Continue reading “Mapping the Interiors of Meteorites to Learn how Earth got its Water”
650 million years ago, Earth was completely or almost completely frozen, according to the Snowball Earth Hypothesis. As the atmosphere changed and Earth warmed up, it heralded the beginning of the Ediacaran Period. The Ediacaran Period marks the first time multicellular life was widespread on the planet. It predates the more well-known Cambrian Period, when more complex life emerged, diversified, and flourished.
Life during the Ediacaran Period faced a mass extinction, and it was Earth’s first one.
What happened?
Continue reading “Earth’s First Known Mass Extinction Event Starved Life of Oxygen”
An asteroid 1.5 km across is no joke. Even a much smaller one, about the size of a house, can explode with more power than the first nuclear weapons. When an asteroid is greater than 1 km in diameter, astronomers call them “planet-killers.” The impact energy released from a planet-killer striking Earth would be devastating, so knowing where these asteroids are and where they’re headed is critically important.
Our defensive capability against asteroid strikes is in its infancy, so advance notice of asteroids that could cross Earth’s orbit is critical. We’ll need time to prepare.
Continue reading “Three New Potentially Hazardous Asteroids Discovered, Including a big one That Measures 1.5 km Across”
Most of us don’t think about ozone as we go about our daily lives. Yet, this pale blue gas plays a huge role in keeping our planet habitable. There’s a layer of it in Earth’s stratosphere, and it absorbs most of the ultraviolet radiation streaming from the Sun. Without the ozone layer, the UV would cause severe damage to most life on Earth. What would happen if we had an ozone hole?
Continue reading “Good News! The Ozone Hole is Continuing to Shrink”