Sound DOES Travel in Space (and 10 Other Space Things You Got Wrong)

About this video

• Video Title: Sound DOES Travel in Space (and 10 Other Space Things You Got Wrong)
• Channel: SciShow
• Speakers: Hank Green
• Duration: 00:16:08

Overview

This video debunks common misconceptions about space, astronomy, and physics. Host Hank Green uses a "Aristotle Scale of Wrongness" to rate the accuracy of these myths, explaining the scientific reasoning behind why they are incorrect and what the reality is.

Key takeaways

• The Moon's "Dark Side" vs. Far Side: The "dark side" of the Moon is the half not illuminated by the Sun, while the "far side" is the half never visible from Earth. Both exist, but the terms are often confused.
• Polaris (North Star) Brightness: Polaris is not exceptionally bright; it's only in the top 50 brightest stars and Sirius is 25 times brighter. Its importance for navigation is due to its position, not its luminosity.
• Water and Organic Matter in Space: Water is common in space as ice and vapor, formed from abundant hydrogen and oxygen. Organic molecules are also widespread, existing independently of life.
• The Sun's Nature: The Sun is not a ball of fire but a glowing ball of plasma, powered by nuclear fusion, not chemical combustion.
• Nebula Density: Nebulas appear dense and opaque in images due to their vast scale and light-years of depth, but in reality, they are extremely diffuse, with far fewer particles per cubic centimeter than Earth's atmosphere.
• Outer Space Temperature: Space itself has no temperature as it's a vacuum. Objects in space experience extreme temperature variations depending on their proximity to stars and their ability to retain heat.
• Sound in Space: While space is largely a vacuum, it's not a perfect one. Sound (or acoustic waves) can travel through the sparse matter in space, and objects can transmit sound through direct contact (like helmet-to-helmet).
• Photograph of the Milky Way: We do not have a true top-down photograph of the Milky Way. Images seen are artist's concepts or models based on data and observations of other galaxies.
• Heliocentric vs. Barycentric Model: While commonly taught that planets orbit the Sun, technically, all bodies in the solar system, including the Sun, orbit a common center of mass called the barycenter, which can sometimes be outside the Sun itself.
• Closest Planet to Earth: The "closest planet to Earth" is not static. While Venus can get very close, Mercury is often closer due to its smaller, tighter orbit. On average, Mercury is the closest planet to all planets in the solar system.
• Why Objects Burn Up in Atmosphere: Objects burning up upon atmospheric entry is not primarily due to friction. It's caused by the object colliding with air molecules at high speeds, creating a superheated plasma that erodes the object.
• The Sun's Color: The Sun is technically white, emitting all colors of the visible spectrum. Apparent yellow or green hues are due to atmospheric effects or the distribution of emitted light.