Astronomy: English Vocabulary List

a region beyond Neptune in the solar system containing icy objects like dwarf planets, asteroids, and comets

"The Kuiper belt has many comets."

"The Kuiper Belt is a vast region of the outer solar system containing dwarf planets and icy bodies"

a highly energetic celestial object emitting powerful radiation from the center of a galaxy, often associated with a supermassive black hole

"A quasar is very far away."

"A quasar is an extremely luminous and distant galactic nucleus"

a distant, hypothetical region surrounding the solar system, thought to harbor icy bodies and comets

"The Oort cloud surrounds our solar system."

"The Oort cloud is a theoretical spherical shell of icy objects surrounding our solar system far beyond Pluto."

the apparent displacement or difference in the apparent position of an object when viewed along two different lines of sight, often used in astronomy to measure the distance of nearby stars

"Astronomers use parallax to measure the distance to nearby stars in space."

"Parallax is the apparent shift in an object's position when viewed from different angles"

a highly magnetized, rotating neutron star that emits beams of electromagnetic radiation from its magnetic poles

"The pulsar sends regular radio signals."

"Scientists discovered a distant pulsar that rotates several hundred times per second."

a unit of measurement equal to the average distance between the Earth and the Sun, approximately 149.6 million kilometers

"One astronomical unit."

"Earth is one astronomical unit from the Sun."

a unit of astronomical distance equivalent to about 3.26 light-years

"It is three parsecs away."

"A parsec is a unit used to measure large interstellar distances."

a high-energy particle, mainly originating from outside the Solar System, that travels through space at nearly the speed of light

"Cosmic rays hit Earth."

"Cosmic rays are high energy particles from outer space that constantly bombard the Earth's atmosphere."

(cosmology) the faint glow of radiation spreading through the universe, believed to be residual radiation from the Big Bang

"The cosmic microwave background."

"The cosmic microwave background is leftover radiation from the Big Bang."

(cosmology) a theory proposing that the solar system formed from a rotating nebula of gas and dust about 4.6 billion years ago

"The nebular hypothesis."

"The nebular hypothesis explains how the solar system formed from a cloud of gas."

(cosmology) a measure of the rate at which the universe is expanding, determined from the observation of distant galaxies' recession velocities

"The Hubble constant."

"The Hubble constant measures the current expansion rate of the universe."

the matter and radiation that exists in the space between stars within a galaxy

"The interstellar medium."

"The interstellar medium is the matter between stars in a galaxy."

the space surrounding the Sun dominated by solar wind

"The heliosphere surrounds our solar system."

"The heliosphere is the vast bubble like region of space surrounding our solar system that is filled with charged particles from the sun."

very small particles originally derived from stars, serving as raw material for forming planets, and existing between galaxies, stars, and other celestial bodies

"Cosmic dust exists everywhere."

"Cosmic dust consists of tiny particles in space."

a small celestial body that becomes visible as a meteor upon entrance into the atmosphere of the earth

"A meteoroid entered the atmosphere."

"A meteoroid becomes a meteor when it burns in Earth's atmosphere."

a disruption in earth's magnetic field caused by solar activity, resulting in variations that can impact electronic systems and communications on earth

"A magnetic storm hit."

"A powerful magnetic storm can disrupt satellite communications and cause beautiful auroras near the poles."

the colored lights, mainly green and red, in the sky seen primarily near the southern magnetic pole

"We saw aurora australis."

"The aurora australis lights up the southern sky with green and pink curtains of light."

the colored lights, mainly green and red, in the sky seen primarily near the northern magnetic pole

"Aurora borealis is beautiful."

"Tourists travel to Norway and Iceland to see the aurora borealis dancing across the night sky."

associated with the phenomena, processes, or theories related to the origin and formation of the universe or celestial bodies

"The theory is cosmogonic."

"The cosmogonic myth explains how the universe was created, and many ancient cultures have their own stories about the origin of the world."

study of celestial objects outside the Milky Way galaxy

"She studies extragalactic astronomy."

"Extragalactic astronomy focuses on objects outside our Milky Way galaxy."

relating to or resembling a nebula, which is a cloud of gas and dust in outer space

"The hypothesis is nebular."

"The nebular hypothesis suggests that the solar system formed from a giant cloud of gas and dust that collapsed under its own gravity."

relating to the stars or constellations, especially in terms of their positions relative to Earth

"The day is sidereal."

"The sidereal day is about four minutes shorter than the solar day because it measures the time it takes for the Earth to rotate relative to the stars."

the outer layer of the Sun's atmosphere, observable as a plasma halo during a solar eclipse

"The sun's corona is very hot."

"The corona is the outermost layer of the Sun's atmosphere"

the apparent path that the Sun traces in the sky over the course of a year, which is also the plane of the Earth's orbit around the Sun

"The ecliptic is the sun's path."

"The ecliptic is the apparent annual path of the Sun on the celestial sphere"

(cosmology) the rapid expansion of the universe following the Big Bang

"Inflation expanded the universe."

"Cosmological inflation theorizes an extremely rapid expansion of the universe shortly after its inception."