Members Can Post Anonymously On This Site
By Amazing Space
NASA LIVE Views From The International Space Station ISS
Some 74,000 years ago, the Toba volcano in Indonesia exploded with a force 1,000 times more powerful than the 1980 eruption of Mount St. Helens. The mystery is what happened after that – namely, to what degree that extreme explosion might have cooled global temperatures.
Crew aboard the International Space Station photographed the eruption of Mount Etna in Sicily in October 2002. Ashfall was reported more than 350 miles away. When it comes to explosive power, however, no eruption in modern times can compare with a super eruption – which hasn’t occurred for tens of thousands of years. NASA When it comes to the most powerful volcanoes, researchers have long speculated how post-eruption global cooling – sometimes called volcanic winter – could potentially pose a threat to humanity. Previous studies agreed that some planet-wide cooling would occur but diverged on how much. Estimates have ranged from 3.6 to 14 degrees Fahrenheit (2 to 8 degrees Celsius).
In a new study in the Journal of Climate, a team from NASA’s Goddard Institute for Space Studies (GISS) and Columbia University in New York used advanced computer modeling to simulate super-eruptions like the Toba event. They found that post-eruption cooling would probably not exceed 2.7 degrees Fahrenheit (1.5 degrees Celsius) for even the most powerful blasts.
“The relatively modest temperature changes we found most compatible with the evidence could explain why no single super-eruption has produced firm evidence of global-scale catastrophe for humans or ecosystems,” said lead author Zachary McGraw, a researcher at NASA GISS and Columbia University.
To qualify as a super eruption, a volcano must release more than 240 cubic miles (1,000 cubic kilometers) of magma. These eruptions are extremely powerful – and rare. The most recent super-eruption occurred more than 22,000 years ago in New Zealand. The best-known example may be the eruption that blasted Yellowstone Crater in Wyoming about 2 million years ago.
Small Particles, Big Questions
McGraw and colleagues set out to understand what was driving the divergence in model temperature estimates because “models are the main tool for understanding climate shifts that happened too long ago to leave clear records of their severity.” They settled on a variable that can be difficult to pin down: the size of microscopic sulfur particles injected miles high into the atmosphere.
In the stratosphere (about 6 to 30 miles in altitude), sulfur dioxide gas from volcanoes undergoes chemical reactions to condense into liquid sulfate particles. These particles can influence surface temperature on Earth in two counteracting ways: by reflecting incoming sunlight (causing cooling) or by trapping outgoing heat energy (a kind of greenhouse warming effect).
Over the years, this cooling phenomenon has also spurred questions about how humans might turn back global warming – a concept called geoengineering – by intentionally injecting aerosol particles into the stratosphere to promote a cooling effect.
The researchers showed to what extent the diameter of the volcanic aerosol particles influenced post-eruption temperatures. The smaller and denser the particles, the greater their ability to block sunlight. But estimating the size of particles is challenging because previous super eruptions have not left reliable physical evidence. In the atmosphere, the size of the particles changes as they coagulate and condense. Even when particles fall back to Earth and are preserved in ice cores, they don’t leave a clear-cut physical record because of mixing and compaction.
By simulating super-eruptions over a range of particle sizes, the researchers found that super-eruptions may be incapable of altering global temperatures dramatically more than the largest eruptions of modern times. For instance, the 1991 eruption of Mount Pinatubo in the Philippines caused about a half-degree drop in global temperatures for two years.
Luis Millán, an atmospheric scientist at NASA’s Jet Propulsion Laboratory in Southern California who was not involved in the study, said that the mysteries of super-eruption cooling invite more research. He said the way forward is to conduct a comprehensive comparison of models, as well as more laboratory and model studies on the factors determining volcanic aerosol particle sizes.
Given the ongoing uncertainties, Millán added, “To me, this is another example of why geoengineering via stratospheric aerosol injection is a long, long way from being a viable option.”
The study, titled “Severe Global Cooling After Volcanic Super-Eruptions? The Answer Hinges on Unknown Aerosol Size,” was published in the Journal of Climate.
By Sally Younger
Earth Science News Team
NASA’s Jet Propulsion Laboratory, Pasadena, Calif.
Last Updated Mar 01, 2024 LocationJet Propulsion Laboratory Related Terms
Earth Earth's Atmosphere General View the full article
By European Space Agency
Space has led to technological innovations with wide-ranging applications in healthcare. Beyond consumer gadgets, such as wireless headsets and scratch-resistant lenses, space exploration is a catalyst for understanding the human body and advancing scientific results that benefit people worldwide. Here are Europe’s top 5 stories in space for your health.
Gravity affects everything we do and everything that happens inside and around us. On Earth’s surface, everything is subject to an average gravitational acceleration of 9.81 m/s2, or what we call 1 g. This acceleration keeps us grounded but it also influences all reactions and phenomena around us, from falling apples to cell growth.
Microgravity conditions allow scientists to study phenomena free from the influence of gravity and investigate in depth the fundamental mechanisms at play. The International Space Station provides uninterrupted periods of weightlessness and offers the opportunity for scientists to conduct research, with the help of astronauts on board, that would be impossible to perform on Earth.
View the full article
By European Space Agency
Image: This Copernicus Sentinel-2 image features the ice tongue of the Dawson-Lambton Glacier in Antarctica. View the full article
By European Space Agency
Video: 00:07:30 Meet the people working on the testing of Ariane 6. Europe’s next rocket, Ariane 6, has passed all its qualification tests in preparation for its first flight, and now the full-scale test model will be removed from the launch pad to make way for the real rocket that will ascend to space.
To make way for launch, teams from ArianeGroup, France’s space agency CNES and ESA have started to remove the Ariane 6 test model by disconnecting the cables and fuel lines that pass through the launch tower.
Find out about the progress being made at the end of testing by the people who know Ariane 6 best. Featuring interviews with ESA’s launch system architect Pier Domenico Resta, CNES Inspector General Bernard Chemoul, CNES Ariane 6 project manager Olivier Bugnet, ESA Launch system engineer Frank Saingou, ArianeGroup system test program manager Valérie and ArianeGroup production engineering manager Lydia Amakoud.
Ariane 6 is an all-new design, created to succeed Ariane 5 as Europe's heavy-lift launch system. With Ariane 6's upper stage restart capability, Europe's launch capability will be tailored to the needs of multiple payload missions, for example to orbit satellite constellations. This autonomous capability to reach Earth orbit and deep space supports Europe's navigation, Earth observation, scientific and security programmes. Ongoing development of Europe's space transportation capabilities is made possible by the sustained dedication of thousands of talented people working in ESA's 22 Member States.
View the full article
Check out these Videos