50 space terms for understanding the universe
Oct. 1, 2019, marks the 61st birthday of the National Aeronautics and Space Agency, or NASA. The agency was founded in 1958, the same year President Dwight D. Eisenhower signed the National Aeronautics and Space Act and one year after the Soviets launched Sputnik 1, the world’s first artificial satellite. NASA was designed from the start to push the bounds of space exploration with research into aerospace and aeronautics as well as with a civilian space program.
From putting footprints on the moon in 1969, to launching satellites into space in 1972 to take images of the Earth’s surface, to a proposed 2020 mission to gather samples from Mars, NASA continues to expand our understanding of the vastness of space and change the way we perceive our solar system (and all that lays beyond it). NASA has gathered unimaginable footage, created first-hand accounts of space, and fostered cutting-edge research. Through the creation of new technologies and procedures, NASA created a foundation of ideas that were previously only theories.
As the agency unrelentingly forged a path toward astronomical discovery, NASA also invented a number of technologies that we use in our everyday lives. These include artificial limbs, LASIK surgery, improved water filtration, camera phones, freeze-dried foods, memory foam, LED lights, and even the Dust Buster. In fact, it was a NASA scientist who invented the Super Soaker squirt gun. In honor of NASA’s birthday, Stacker has compiled a list of key astronomy and astrophysics terms from a variety of authoritative science communication sources, including Crash Course: Astronomy, How Stuff Works, and International Comet Quarterly. Keep reading to learn the terms that are commonly used in this fascinating field.
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#1. Aberration of light
Similar to how raindrops hit a moving car window as if from an angle, an aberration of light is the phenomenon where stars or other celestial bodies appear from Earth to be slightly off from their true position. This happens because of motion—specifically, the interaction of the Earth’s movement with the speed of light causes this confusing phenomenon.
[Pictured: The bright vertical line and the other rays with barred lines are aberrations caused by the bright flash of the solar flare in a sunspot, 2017.]
#2. Alpha Centauri
Alpha Centauri is the name of the closest star system to earth. It comprises two main stars, Alpha Centauri A and Alpha Centauri B, as well as the closest of the three stars, Proxima Centauri. In 2016, astronomers found an Earth-sized planet orbiting Proxima Centauri, later named Proxima b. While this planet shows signs that life could exist, astronomers are still unsure how habitable it is.
[Pictured: Alpha Centauri (left) and Beta Centauri (right).]
#3. Andromeda Galaxy
Also known as M31, this galaxy is the closest to the Milky Way, where the Earth exists. Andromeda Galaxy has a similar structure to the Milky Way; it is spiral in shape and has a large density of stars, dust, and gas. Because of its proximity, it is the only galaxy that can be seen from Earth with the unaided eye, particularly on fall and winter nights.
Asteroids are chunks of rock or metal that used to be parts of other small planets that have broken off due to a collision in space and now orbit the sun. The name asteroid means “star-like.” referring to their emission of light. Asteroids can be lumped into orbital groupings called families and form into an asteroid belt.
A barycenter is the common center mass around which a solar system orbits. While it has become common knowledge that planets orbit stars, it is, in fact, the barycenter that both stars and planets orbit around. Our solar system’s barycenter is constantly changing position based on where each of the planets is in its orbit, ranging from being near the center of the sun to being just outside its surface.
#6. Big Bang
The Big Bang Theory is a model describing the origin of the universe. It explains how the universe expanded from a high-density, high-temperature state into the cosmos we see today. Although there are alternative theories, this is the most widely recognized theory of how the universe began.
[Pictured: Hubble Space Telescope observed one of the most massive known galaxy clusters, RX J1347.5–1145.]
#7. Binary star
Binary stars are systems that only contain two stars that orbit together. Together, they orbit a common center of mass. There are two types of binary stars: wide binaries and close binaries. Wide binaries orbit with a significant distance apart from each other, causing them to have little effect on each other. Close binaries orbit closely and actually can acquire material from one another.
[Pictured: An artist's depiction of the binary star series, J0806.]
#8. Black hole
Made famous by Einstein’s theory of general relativity, a black hole is the small dense core remnant of a dead star. Since the density of this core is more than about three times more than the density of the sun, the strong force of gravity produces a black hole.
[Pictured: Artist's concept of a supermassive black hole.]
#9. Brown dwarf
A brown dwarf is born from a collapse of gas and dust, similar to stars. This collapse creates a large amount of energy that gets trapped in a ball of material. The energy emits light from within for tens of millions of years, becoming dimmer as time passes.
[Pictured: Artist's concept of a brown dwarf with bands of clouds.]
#10. Celestial sphere
A celestial sphere is a tool used in spherical astronomy. It is a sphere with a large radius that is concentric with Earth. The sky surrounding the Earth is projected on the sphere, which is helpful for astronomers when they are attempting to plot positions in situations where distances aren’t important.2018 All rights reserved.