Mars Might Have Lost its Water Quickly

Mars is an arid place, and aside from a tiny amount of water vapour in the atmosphere, all water exists as ice. But it wasn’t always this arid. Evidence of the planet’s past wet chapter dots the surface. Paleolakes like Jezero Crater, soon to be explored by NASA’s Perseverance Rover, provide stark evidence of Mars’ ancient past. But what happened to all that water?

It disappeared into space, of course. But when? And how quickly?

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Scientists in Japan Have Found a Detailed Record of the Earth’s Last Magnetic Reversal, 773,000 Years Ago

Every 200,000 to 300,000 years Earth’s magnetic poles reverse. What was once the north pole becomes the south, and vice versa. It’s a time of invisible upheaval.

The last reversal was unusual because it was so long ago. For some reason, the poles have remained oriented the way they are now for about three-quarters of a million years. A new study has revealed some of the detail of that reversal.

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Ancient Meteorites Can be Found Embedded in Rocks, Like Fossils

Comets visit the inner Solar System, and leave without saying goodbye. Maybe they leave a trail of dust behind, and when the Earth passes through it, we get a pretty light show in the night sky, in the form of a meteor shower. Likewise, asteroids frequently go whizzing by, though they don’t leave us with a pyrotechnic display.

Sometimes these rocky interlopers head straight for Earth. And when they do, the results can be cataclysmic, like when an asteroid struck Earth about 66 million years ago, wiping out the dinosaurs and 75% of life on Earth. Other times, it’s not quite as cataclysmic, but still devastating, like in about 2350 BC, when debris from a disintegrating comet may have caused the collapse of an ancient empire.

But regardless of the severity of any of these individual events, the conclusion is crystal clear: Earth’s history is intertwined with the coming and going of space rocks. The evidence is all around us, sort of.

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NASA’s Long-Term Climate Predictions have Proven to be Very Accurate, Within 1/20th of a Degree Celsius

There are a handful of major science institutions around the world that keep track of the Earth’s temperature. They all clearly show that the world’s temperature has risen in the past few decades. One of those institutions is NASA.

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Astronomy Cast Ep. 516: Polar Vortices

It’s cold right now. Okay, fine, here on Vancouver Island, it’s actually pretty warm. But for the rest of Canada and big parts of the US, it’s terrifyingly cold. Colder than Mars or the North Pole cold. This is all thanks to the break up of the polar vortex. What are polar vertices, how do they form, and where else to we find them in the Solar System?

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We Have the Technology. Airplanes Could Spray Particles into the Atmosphere to Battle Climate Change. But Should We?

Our beautiful, precious, life-supporting Earth as seen on July 6, 2015 from a distance of one million miles by a NASA scientific camera aboard the Deep Space Climate Observatory spacecraft. Credits: NASA

If climate change models are correct, humanity is working itself—and dragging the rest of life on Earth with it—into a corner. Scientific pleas to control emissions and battle climate change are starting to have some effect, but not enough. So now we have some tough decisions looming.

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Satellite Images Show a Trillion Ton Iceberg Broke Off Antarctica

For several months, scientists have been keeping an eye on a piece of Antarctica’s Larsen C ice shelf, waiting for the inevitable. And now it has happened.

Sometime between July 10 and July 12, 2017 a trillion ton iceberg split off, “changing the outline of the Antarctic Peninsula forever,” said one scientist.

The new iceberg is now called A68, and at 2,240 square miles (5,800 square km) it is one of the biggest ever recorded, about the size of Delaware in the US, or twice the size of Luxembourg.

A fissure on the ice shelf first appeared several years ago, but seemed relatively stable until January 2016, when it began to lengthen. In January 2017 alone, the crack grew by 20 km, reaching a total length of about 175 km.

Witnessed by the Copernicus Sentinel-1 mission on 12 July 2017, a large iceberg has broken off the Larsen-C ice shelf, one of the largest icebergs on record. Credit: Modified Copernicus Sentinel data (2017), processed by ESA.

The calving of the iceberg was confirmed by the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite and was reported this morning by Project MIDAS, an Antarctic research project based in the UK.

The MODIS instrument on NASA’s Aqua satellite also confirmed the complete separation of the iceberg.

Larsen C is a floating platform of glacial ice on the east side of the Antarctic Peninsula, is the fourth largest ice shelf ringing Earth’s southernmost continent. With the break-off of this iceberg, the Larsen C shelf area has shrunk by approximately 10 percent.

Some scientists say the Larsen C rift and iceberg calving is not a warning of imminent sea level rise, and linking climate change to this specific event is complicated. Adrian Luckman, Professor of Glaciology and Remote Sensing from Swansea University wrote a detailed explanation of this for The Conversation.

The new iceberg would barely fit inside Wales. Credit: Adrian Luckman / MIDAS

David Vaughan, glaciologist and Director of Science at British Antarctic Survey (BAS), said, “Larsen C itself might be a result of climate change, but, in other ice shelves we see cracks forming, which we don’t believe have any connection to climate change. For instance on the Brunt Ice Shelf where BAS has its Halley Station, there those cracks are a very different kind which we don’t believe have any connection to climate change.”

While Vaughan said they see no obvious signal that climate warming is causing the whole of Antarctica to break up, he added that there is little doubt that climate change is causing ice shelves to disappear in some parts of Antarctica at the moment.

“Around the Antarctic Peninsula, where we saw several decades of warming through the latter half of the 20th century, we have seen these ice shelves collapsing and ice loss increasing,” he said. “There are other parts of the Antarctica that which are losing ice to the oceans but those are affected less by atmospheric warming and more by ocean change.

Scientists said the loss of such a large piece is of interest because ice shelves along the peninsula play an important role in ‘buttressing’ glaciers that feed ice seaward, effectively slowing their flow.

“The interesting thing is what happens next, how the remaining ice shelf responds,” said Kelly Brunt, a glaciologist with NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and the University of Maryland in College Park. “Will the ice shelf weaken? Or possibly collapse, like its neighbors Larsen A and B? Will the glaciers behind the ice shelf accelerate and have a direct contribution to sea level rise? Or is this just a normal calving event?”

The U.S. National Ice Center will monitor the trajectory of the new iceberg, but they don’t expect it to travel far very fast, and it shouldn’t cause any immediate problems for navigation of ships.

See additional imagery and animations from Goddard Space Flight Center.

Sources and additional reading:
ESA, British Antarctic Survey, NASA.