This Scientist Sunday goes to Harlow Shapley (1885–1972), the astronomer who figured out our true place in the Milky Way! His work shattered the belief that the Sun was at the center of our galaxy, changing our cosmic perspective forever. ⬇️1/6 Shapley began by studying the distribution of globular clusters (dense collections of ancient stars) in the sky. He noted that these clusters were not uniformly distributed, but instead were more concentrated in one part of the sky⬇️2/6

Why do hurricanes spin the way they do? Why do they spin in opposite directions on opposite sides of the equator? It's all thanks to our Earth's rotation and something called the Coriolis Effect! But how does it work? Let's dive in! ⬇️1/6 The surface of the Earth rotates at different speeds depending on latitude. On the equator you move faster eastward than you do close to the poles! ⬇️2/6

The blue sky is a beautiful result of physics in action! But why is it blue? Why does the sky appear more orange-red at sunset? Let's dive in!⬇️1/4

Sunlight, though appearing white, is a mix of many colors. Each color has its wavelength, with blue and violet being the shortest and red the longest. Our atmosphere is mainly tiny molecules of nitrogen and oxygen...⬇️2/4

Ever wondered why soap bubbles, peacock feathers, and oil slicks display a mesmerizing array of colors? It's all thanks to a phenomenon called iridescence. How does it work? Let's dive in! ⬇️1/5 Soap bubbles consist of two layers of soap molecules with water sandwiched in between. Light reflecting off these layers interferes, either amplifying or canceling out certain colors. ⬇️2/5

A simple homopolar motor that you can make at home to demonstrate Lorentz force, electromagnetism, and electric motors! How does it work?⬇️1/4 When the wire touches both the battery and the magnet, it completes an electrical circuit. Current flows (I) from the positive terminal of the battery, through the wire, and into the magnet, finally returning to the negative terminal of the battery.⬇️2/4

Contrary to popular belief, the majority of the Earth's oxygen isn't produced by trees but by tiny ocean plants called phytoplankton. These microscopic heroes contribute between 50 to 80% of the oxygen in our atmosphere!⬇️1/4 Beyond oxygen production, phytoplankton also play a crucial role in the global carbon cycle. They absorb large quantities of CO2 from the atmosphere, mitigating some of the impacts of climate change. When phytoplankton die or are eaten, they can sink to deeper ocean layers.⬇️2/4

Honey never spoils! Archaeologists have even found pots of honey in ancient Egyptian tombs that are over 3,000 years old and still perfectly edible. Why is this the case? Here is a break down⬇️ 1) Low Water Content: Most water in honey is bound with sugar, leaving little free water for microbes to thrive. This lack of available water makes it hard for bacteria to grow.

This Scientist Sunday we're going back to ancient Greece. Aristarchus of Samos (310–230 BC) was an ancient Greek mathematician and astronomer who was centuries ahead of his time. Here's why he's so important!⬇️1/5 He was the first known person to suggest a sun-centered model of the universe. His ideas were so revolutionary that they were largely rejected by his contemporaries. His theory wasn't widely accepted until nearly 2000 years later, when Copernicus and Kepler revived it.⬇️2/5

Leaf-cutter ants are one of the few species that practice a form of agriculture. These ants cut pieces from leaves, bring them back to their colony, and use them as a substrate to grow a specific type of fungus. This fungus serves as the colony's primary food source.⬇️1/2 This farming is quite complex and involves not just farming but also pest control. The ants secrete substances that suppress harmful molds that could harm the fungus, similar to how human farmers might use pesticides. 2/2

There's a common misconception about the word "theory" in science. When you hear, "Evolution is just a theory," remember, in science, a theory isn't a guess or hunch, but a well-substantiated explanation of some aspect of the natural world.⬇️1/6 Let's break down the difference between "fact", "law", and "theory" in science. A "fact" is an observation that's been repeatedly confirmed. It's a fact that an apple falls to the ground when dropped.⬇️2/6

This Scientist Sunday goes to Hedy Lamarr (1914 - 2000). Lamarr was a unique figure in the 20th century as both a glamorous Hollywood actress and a significant inventor. She co-invented a frequency-hopping signal during WWII that is now a part of Wi-Fi, CDMA and Bluetooth.⬇️1/6 Born Hedwig Eva Maria Kiesler in Austria, she made her film debut in the controversial Czech film "Ecstasy" (1933), gaining her recognition in Europe. In 1937, she fled from her controlling husband, who was associated with fascist leaders in Europe, and moved to Hollywood.⬇️2/6

Our bodies are constantly at war, fending off pathogens at the microscopic level. The innate immune system is our body's first line of defense in this never ending battle. It is non-specific and fights anything that tries to invade. Let's dive in deeper!⬇️(1/6) If a pathogen breaches physical barriers like skin or mucus, our Complement System comes into play. It identifies, tags, and even perforates pathogens! Tagged pathogens attract macrophages to engulf and destroy them. Complement helps distinguish self from non-self.⬇️(2/6) twitter.com/i/web/status/1…

To this day we don't have a picture of our home galaxy, from the outside. This is because it is so large that sending a probe far enough to grab the selfie would take far too long. If we can't see it from the outside then how do we know its size and our location within it?⬇️1/6 Harlow Shapley, an American astronomer (1885-1972), began by studying the distribution of globular clusters (dense collections of ancient stars) in the sky. He noted that these clusters were not uniformly distributed, but instead were more concentrated in one part of the sky⬇️2/

This Physicist Friday goes to Lise Meitner. Meitner (1878-1968) was an Austrian-Swedish physicist known for her role in the discovery of nuclear fission. Working with chemist Otto Hahn, they bombarded uranium atoms with neutrons, splitting the nucleus and detecting barium. ⬇️1/4 Meitner, along with her nephew Otto Frisch, interpreted the results using Einstein's E=mc^2 to explain the observed energy release. They realized that the splitting of the atomic nucleus into smaller nuclei released a significant amount of energy.⬇️2/4

Snake venoms are complex mixtures of proteins, peptides, and other molecules that have evolved for various purposes, such as prey immobilization and digestion. This video demonstrates how procoagulants in some snake venom promote blood clotting. How does this work? See Next⬇️1/3 These procoagulants directly interact with proteins involved in the blood clotting process. Often these are proteases (cleave proteins) which ultimately lead to the rapid formation of fibrin, the protein mesh that stabilizes blood clots. ⬇️2/3

Retrograde motion is the apparent backwards motion that planets make as they travel across the sky.
Prior to the sun-centered model of the solar system, it was believed planets made loopty loops as they circled the earth.
The Copernican model explains this motion w/o loops. (1/2) Here's an actual time-lapse image showing what it looks like in the sky. (2/2)
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