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Moon Illusion: The Horizon Moon Is Farther and Smaller
The moon illusion makes a rising Moon look enormous. Measured, that Moon is about 1.66% farther away than the one overhead, and smaller.
Section
Cosmology & Astrophysics
Stars, black holes and the structure of the universe, explained from the measurements up.
17 articles
Primordial Black Hole Candidate S251112cm: Real or Noise?
Primordial black hole hunters have a new candidate, S251112cm — but its 1-in-4-year false alarm rate is barely better than a coin flip.
Plutonium-238 Shortage Will Delay NASA’s Uranus Mission
Plutonium-238 shortage, not budget, is why NASA's Uranus Orbiter may slip past its 2032 launch window into the 2030s.
Webb Telescope Reveals Interstellar Comet 3I/ATLAS Predates Our Sun
Webb's latest data on interstellar comet 3I/ATLAS reveals a 12-billion-year-old cosmic visitor carrying deuterium 30 times higher than any solar system comet — and…
Space-Time and Relativity: How to Imagine It
Space-time isn't a backdrop -- it's a single four-dimensional object that bends, and two thought experiments make that bending intuitive.
What Is the Void? Exploring the Dark Heart of Cosmology
The void, the start and end of our Universe. Discover why we will all be vacuum fluctuations.
The Mystery of Round Planets: Discover the Secret Force
Why are planets round? It appears to be a simple question... but no one knows the answer.
Stephen Hawking: The Physicist Who Explained Black Holes to the World
Discover the major contributions to science made by Stephen Hawking, including black holes and the early life of our universe.
Explore Gravity’s Secrets: A Journey into the Cosmic Unknown
What causes objects to fall? For millennia, this seemingly insignificant question has captivated the greatest minds, driving them to formulate increasingly intricate theories of…
What Is Dark Energy, and How Do Scientists Actually Detect It?
We can't see it and we can't feel it, but we can test for it. Guess, what is it? Ladies and gentlemen let me…
Is the Universe Finite or Infinite? What Physics Actually Says
Cosmologists can't rule out either a finite universe that wraps on itself or a genuinely infinite one -- current data only bounds its curvature…
The Great Filter Theory. Are We Really Alone?
Scientists believe there's a compelling reason for the absence of alien discoveries, hinting at the possibility of human extinction.
How Dark Energy Will End the Universe, According to Physics
As the universe expands, galaxies drift apart and their stars fade into darkness. Discover the epic battle deciding the universe's end.
The Future of Gravitational Wave Detection: The Einstein Telescope
Discover how the Einstein Telescope is going to take gravitational wave astronomy far beyond its giant first steps.
What Happens If You Fall Into a Black Hole? Spaghettification, Explained
Life inside black holes. Learn how spaghettification, time dilation, and point of no return shape the fate of objects venturing too close.