From roughly 60 miles above the Earth's surface to farther than light has traveled during the entire age of the universe, space has captured human imagination for millennia. Explore the final frontier with the best resources curated from across the internet.
Hours of research by our editors, distilled into minutes of clarity.
Beyond this line, approximately 100 kilometers above Earth's surface, aerodynamic lift is insufficient to keep aircraft aloft without special propulsion systems. The United Nations has historically accepted the line as delineating the boundary of space.
One of the most surprising discoveries about our universe over the past century is that it's expanding. Even more surprising is that it’s speeding up, and scientists aren’t entirely sure why. The rate should be roughly dependent on the total energy contained in the universe, but calculations keep coming up short. Explore the so-called “Hubble Tension,” along with potential candidates to solve the riddle.
Mental Floss digs into the history behind the fable, which dates back as far as the 1500s, when it was mentioned in "The Proverbs of John Heywood." Even NASA has gotten in on the joke, tweeting a (supposedly) doctored photograph showing the moon’s expiration date.
In addition to being the first human in space, Yuri Gagarin was a charismatic propaganda icon and a diplomatic headache for the West. This article examines why his image—and legacy—endured long after he died in 1968.
On July 17, 1975, American and Soviet astronauts docked their spacecraft during the Apollo–Soyuz mission, symbolically ending the Space Race and marking the first joint spaceflight between Cold War rivals.
Soviet scientists launched the first satellite, sent the first human into orbit, and carried out early spacewalks—milestones that gave the USSR a decisive early lead in the Space Race and reshaped global competition in science and technology.
Could aliens destroy us from light-years away? The team at Kurzgesagt imagines the impact of a highly sophisticated alien civilization setting out to crush humanity and considers the real-world logistics for warfare conducted across the universe.
Einstein's theory of general relativity—that mass literally bends space and time—can be difficult for the human brain to imagine. This interactive resource lets you create celestial objects, imagine their effect on space-time, and see how they interact with each other (best viewed on desktop).
Gravitational waves sent out from a pair of colliding black holes have been converted to sound waves, as heard in this brief but memorable animation. On Sept. 14, 2015, LIGO observed gravitational waves from the merger of two black holes, each about 30 times the mass of our sun. The incredibly powerful event, which released 50 times more energy than all the stars in the observable universe, lasted only fractions of a second.
Space-time is a complex subject, but this Livescience article makes an effort to disentangle the topic. Somewhat akin to a sheet of rubber that can be warped and bent in parts, space-time is a bit more involved that that. However, the analogy makes this and other aspects of the concept simpler to grasp.