How can we know the size, composition, and atmospheric makeup of distant exoplanets? NASA explains the details in this Alien Atmospheres video.
By observing periodic variations in the parent star’s brightness and color, astronomers can indirectly determine an exoplanet’s distance from its star, its size, and its mass. But to truly understand an exoplanet astronomers must study its atmosphere, and they do so by splitting apart the parent star’s light during a planetary transit.
Watch more astronomy videos, including Measuring the Universe and The Hubble Ultra Deep Field.
via Boing Boing.
Sea Level! What is it and how do scientists calculate it? As it turns out, there are actually many complexities in determining this measurement. For example, Earth isn’t actually a sphere, gravity is stronger and weaker at different points around the globe, and of course, there are a lot of mountains that are no where near water — so how do we know what sea level would be? In this video, Minute Physics explains the details.
After you’ve watched, check out these related links: ellipsoid, geoid, geodesists, Mount Everest, Chimborazo Volcano, Space.com’s Best Gravity Map Yet Shows a Lumpy, Bumpy Earth, and this clarifying and not-to-be-missed animated gif of Earth’s gravity field.
In the archives: videos about or involving measuring things, including Measuring the Universe.