The UniverseAnswer
Are black holes or wormholes doorways to other places?
A tunnel in an equation, a black hole in the sky and a working spacecraft are three different claims.
SECTION
The Universe.
How does the cosmos really work?
Black holes, dark matter, the speed of light, antimatter and the search for a theory of everything—explained plainly, with the evidence labelled.
FROM THE QUESTION LIBRARY
Short answers, with sources.
The UniverseAnswer
Can a Planet Orbit Two Stars?
Two stars can circle each other while a planet travels around them both. Astronomers confirmed it by watching the moving stars dim.
The UniverseAnswer
Could dark matter come in many kinds, with its own hidden forces?
Could dark matter have several particles and hidden forces? Learn what the abundance ratio, dark photons and early-universe element tests actually tell us.
The UniverseAnswer
Could our universe be a thin sheet floating inside a bigger space?
The sheet picture starts a question; a model must explain what moves where and reproduce measured gravity.
The UniverseAnswer
Could the edge of a black hole be less perfect than Einstein’s math says?
What gravitational-wave echoes might reveal about black-hole boundaries, why quantum structure is unconfirmed, and what a convincing detection needs.
The UniverseAnswer
How big can black holes get, and is there one at the center of our galaxy?
Mass, horizon size and a glowing image tell different parts of the story; spin adds another clue.
The UniverseAnswer
How did dark matter shape galaxies and the cosmic web?
How dark matter helped form the cosmic web and galaxies, and why comparing dwarf galaxies with clusters tests possible self-interactions.
The UniverseAnswer
How do we know dark matter exists if we cannot see it?
We can’t see dark matter, but we can measure its pull in five different ways, so here is the evidence, the case for changing gravity instead, and what is still unknown.
The UniverseAnswer
How do we know Earth isn’t the center of the universe?
Earth’s motion, a map’s origin, and a cosmic center are different questions.
The UniverseAnswer
How will the Sun die, and what will happen to Earth?
The Sun’s broad future is well understood, while the final path of Earth depends on uncertain tides and mass loss.
The UniverseAnswer
Is antimatter real, or just science fiction?
Antimatter is measured in nature and laboratories, while its cosmic imbalance remains unexplained.
The UniverseAnswer
Is gravity a force, or a bend in space and time?
The force picture and the spacetime picture explain the same world at different levels of detail.
All 36 answers in The Universe
- Are black holes or wormholes doorways to other places?
- Can a Planet Orbit Two Stars?
- Could dark matter come in many kinds, with its own hidden forces?
- Could our universe be a thin sheet floating inside a bigger space?
- Could the edge of a black hole be less perfect than Einstein’s math says?
- How big can black holes get, and is there one at the center of our galaxy?
- How did dark matter shape galaxies and the cosmic web?
- How do we know dark matter exists if we cannot see it?
- How do we know Earth isn’t the center of the universe?
- How will the Sun die, and what will happen to Earth?
- Is antimatter real, or just science fiction?
- Is gravity a force, or a bend in space and time?
- Is math invented by humans or discovered in nature?
- Is nature perfectly fair between matter and antimatter?
- Is time travel possible?
- What are gravitational waves, and how do we detect them?
- What is a black hole, really?
- What is a theory of everything, and will we ever have one?
- What is an extra dimension, and why can’t we see one?
- What is empty space actually made of?
- What is string theory, and why hasn’t it been tested yet?
- What Is the Higgs Field, and Why Call Its Particle the “God Particle”?
- What is the Standard Model of particle physics, and what does it leave unexplained?
- What is time, and why does it only seem to move forward?
- What would happen if you could send a message faster than light?
- When we look at the stars, what are we really seeing?
- Where did the gold in a wedding ring come from?
- Where does antimatter show up in everyday life?
- Why do physicists still call the matter-antimatter imbalance unsolved?
- Why does a newborn black hole ring like a struck bell?
- Why does nature come with three families of particles, like the electron, muon and tau?
- Why is the expansion of the universe speeding up?
- Why is the night sky dark if there are so many stars?
- Why is the speed of light the universe’s speed limit?
- Why is there any matter left in the universe at all?
- Will the universe end, and if so, how?
The UniverseEssay · personal view
Night Is Just Earth’s Shadow, and We Are Stardust
Two ordinary truths—the turning of Earth and the atoms inside our bodies—can make the sky feel much closer than it did before.
The UniverseExplainer
What Is a Black Hole, Really?
Not really holes and not cosmic vacuum cleaners, black holes are places where matter is packed so tightly that not even light can climb back out.
The UniverseExplainer
What Is Dark Matter?
Galaxies spin too fast and light bends too much, so something unseen seems to be out there, but nobody yet knows what it is.
The UniverseExplainer
What Is Dark Energy?
In 1998 astronomers found that the universe's expansion is speeding up, and "dark energy" is the name for a cause nobody yet understands.
The UniverseExplainer
Can Anything Travel Faster Than Light?
Shadows, stretching space and a famous neutrino scare all seem to break the cosmic speed limit. Here is why the limit still stands.
The UniverseExplainer
Why Is There More Matter Than Antimatter?
The Big Bang should have left an almost empty universe. A tiny surplus of matter built everything we know, and nobody yet knows why.
The UniverseExplainer
Is There a Theory of Everything?
Physicists have merged forces of nature before. Gravity is the holdout, and no candidate theory of everything has yet passed a decisive test.