Vicky Stein

Reference Ursa Major, also known as the Great Bear, is the third-largest constellation in the sky. We explore this well-known constellation in more detail here.

Reference The Goldilocks zone or habitable zone is the region around a star where an orbiting planet could host liquid water and, therefore, possibly support life.

Reference Planetary defense refers to the effort to monitor and protect Earth from asteroids, comets and other objects in space.

Reference The legacy of Arecibo's nearly 60 years of astronomy research is strong, even after its loss in a dramatic 2020 collapse.

Reference The Southern Cross has long been a celestial landmark for explorers and travelers. The iconic group of stars is visible mainly from the Southern Hemisphere.

Reference Aquarius is a constellation in the Western Zodiac that is best viewed in the fall. The constellation is one of the oldest constellations documented in the historical record.

Reference Didymos is a binary asteroid system that NASA's DART mission visited during the agency's first planetary defense mission.

Reference Jupiter is the biggest planet in the solar system and has 79 moons. Learn more about the gas giant in our ultimate guide.

Reference Astronomical twilight is the darkest phase of twilight that a viewer sees before the last refracted sunlight leaves the horizon. It usually occurs twice a day.

Reference The constellations of the western zodiac are now used to orient skywatchers, navigate without technology and inspire interest in the night sky.

Reference Mars missions have been launching for over 50 years. Humanity has sent orbiters, probes and landers to Mars but not every mission has been successful.

Reference Earth's global average surface temperature is approximately 59 degrees Fahrenheit (15 degrees Celsius). But it's on the rise.

Two dozen so-called superhabitable alien worlds may be as good as or better than Earth for life as we know it.

Earth and even the sun are puny compared to a mighty, hulking source of gamma-rays.

Reference The largest known star in the universe is UY Scuti, a hypergiant with a radius around 1,700 times larger than the sun.

Reference Space shuttle Challenger exploded just 73 seconds after liftoff on Jan. 28, 1986, changing NASA's space program forever.

Why is Polaris called the North Star and how is it used?

Reference The speed of light puts a speed limit on matter, lets us peer back into the history of our universe, and has deep implications for physics and space travel.

Reference String theory is the idea in theoretical physics that reality is made up of infinitesimal vibrating strings, smaller than atoms, electrons or quarks.

REFERENCE Inspiration4 was the world's first orbital spaceflight unsupervised by professional astronauts, using commercial equipment to launch civilian space enthusiasts into orbit.

Reference You are time-traveling right now, but how does real time travel differ to that of science fiction? Here, we explore some of the theories behind time travel and the science that supports time-bending.

Reference There are a few good theories for a multiverse — an infinite number of parallel universes besides our own.

Reference Though we can now be certain the asteroid Apophis will not strike Earth in 2029, its close passage offers us a unique scientific opportunity.

Einstein's paper on special relativity revolutionized light, light speed, matter and energy with a deceptively simple equation.