June 26, 2023: Gravity hole under the Indian Ocean, why some people are always sick and California's largest lake is drying up. Read it all below! —Andrea Gawrylewski, Chief Newsletter Editor | | | There's a hole under the Indian Ocean. Spanning more than three million square kilometers, the gouge is centered about 1,200 km southwest of the southern tip of India. Because of a low pull of gravity there, combined with higher gravity in surrounding areas, the sea level over the hole is 106 meters lower than the global average, according to a new study.
Why this is cool: Earth is not perfectly round. Rather, it is flatter at the poles and bulges around the equator, with other irregular peaks and valleys caused by different regions' mass exerting different gravitational pulls. The hole under the Indian Ocean is the planet's most prominent gravitational anomaly.
What the experts say: Slabs of the floor of an ancient sea called the Tethys Ocean which existed 200 million years ago sank into the mantle, creating plumes of molten rock. The hole under the Indian Ocean probably took its present shape about 20 million years ago, when the plumes started to spread within the upper mantle, says Debanjan Pal, a doctoral student at the Indian Institute of Science in Bangalore, and lead author of the new study. | | | An exaggerated visualization of our planet's gravitational high and low spots called the global geoid. Credit: Science History Images/Alamy Stock Photo | | |
Key factors at play: The first factor is genetic propensity to become infected more readily. The second is environmental–a heavy burden of infection where someone works, for example, like in a hospital or classroom. And the last factor is how the body handles inflammation, which is different in each person.
What the experts say: Although we can't predict how often or severely one person gets sick, some ways to ward off infection include regular sustained exercise and mask wearing by vulnerable populations, says Sunil Ahuja, a professor of medicine at the University of Texas Health Science Center at San Antonio. | | | Toxic Drying Sea East of Los Angeles, there's a landlocked salty lake called the Salton Sea. Once advertised as a swanky tourist destination in the 1950s and 60s, it's now drying up. Toxic dust from the exposed lake bed is severely impacting the health of local residents. Listen to this episode of Science, Quickly, which dives into how communities and scientists are working together to figure out what makes the lake so poisonous to humans. | | | • Comet Tsuchinshan-ATLAS is on track to zip quite close to the sun and Earth in the autumn of 2024, when it should be a remarkable celestial display. | 4 min read | | | • Privately owned space colonies are more likely to be totalitarian nightmares than libertarian utopias, writes Matthew R. Francis, physicist and journalist. "Tech billionaires in general appear fond of writing their own rules while rejecting others' legal authority," even with governments watching over their shoulders, he says; so why would we expect them to behave better off Earth? | 5 min read | | | Welcome to a new week! We've got some exciting news heading your way, especially in the space and physics realm, so stay tuned! A merciless "heat dome" has settled over Texas, keeping the state locked in the swelter. In case you missed it last week, here's one of our latest features on the dangers of extreme heat. Sadly I fear this will continue to become more common in the years ahead. | Please let me know how you're liking this newsletter (or not? I can take it) by emailing me at newsletters@sciam.com. | —Andrea Gawrylewski, Chief Newsletter Editor | | Subscribe to this and all of our newsletters . | | | | Scientific American
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