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Showing posts from June, 2020

Why there is Land?

 Earth has land. You know that — the odds are pretty goodyou’re on some of it right now. But here’s a weird thing to think about:It’s possible that land didn’t always exist. And technically-speaking, it doesn’t /have/to. I mean, if you were just to simply smooth out the Earth’scrust, the oceans contain enough water to cover the planet in a sea more than two kilometersdeep. So… why does land exist? Why is it so varied, with all those mountainsand valleys and flat plains? And — here’s a fun one: Could anythingever get rid of land on Earth? To answer those questions, which god knowsI want to do, you need to travel back more than four billion years.  Billions of years ago, Earth started as acloud of dust and grains left over from the Sun’s formation. Then, over time, those pieces slowly balledtogether into proto-Earth. That ball was made of all kinds of elements. And as it aged, the denser ones, like iron,sank towards the center of the ball to become Earth’s core, while lighter on...

How Cells Hack Entropy to Live 2020

Hello i am Dhruv One of the most fundamental ideas in physics is that the disorder of the universe is constantly increasing. Which is funny, because life as we understand it is pretty darn… ordered. And it turns out life’s inherent chemicalmakeup has been hacking the disorder of the universe for billions of years. To understand this disorder, otherwise known as entropy, imagine you have given a bag of glitter to a toddler.  Is all that glitter going to stay in the bag?No, probably not. And once it’s out there, it’s there forever.It’s not going back in the bag. You’re just going to have to make peace with glitter being a permanent feature of your floors, your furniture, maybe even your food and hair and skin. But your two-year-old force of nature wasonly abiding by the second law of thermodynamics.  The second law holds that entropy, which is a measure of how spread out the energy of a system is, is constantly increasing. Initially, your bag of glitter had low entropy because...

How Long Does SARS-CoVID-19 Last on Surfaces?

. If a surface is contaminated with the SARS-CoV-2virus, how long does it pose a risk of infection? The virus is thought to mainly spread throughrespiratory droplets. These are produced in a cloud when a personcoughs or sneezes, or even talks. Some potentially-virus-laden droplets mightend up getting breathed in by other people in the vicinity. But many of them end up landing on objectslike door handles or water faucets.  When that happens, infectious disease expertsrefer to that door handle as a fomite. And if a person then touches the fomite whilethe virus is still infectious, they can then spreadit to new surfaces, or actually infect themselves. Fomites aren’t just for viruses -- any typeof pathogen can create fomites -- but we’re talking about virusesfor… obvious reasons.  The good news is that SARS-CoV-2 virus particlesdon’t last forever -- or even all that long. Eventually, the protein coat that allows thevirus to actually bind to and infect cells will degrade. This ne...