Black holes
How can we learn about black holes if they trap light, and can't actually be seen?
Light, including X-rays, cannot escape from inside a black hole's event horizon. NASA's telescopes observe the surrounding areas where material near the event horizon is heated to millions of degrees and emits X-rays. The immense gravity of black holes distorts space, allowing the influence of their gravitational pull on nearby stars and objects to be observed.
The Sun is on fire.
False!!! The sun is hot but not on fire. Fire is made by oxygen while there's no oxygen on The Sun.
Even if the universe is infinite, it can still expand. Expansion in this context refers to the increasing distance between gravitationally unbound objects (like galaxies) within the universe, not the universe growing into something larger. It's like an infinite elastic sheet where you can stretch the distances between points on the sheet without needing an edge.
How long does it take to make a black hole?
A stellar-mass black hole, formed from a massive star's collapse, can develop in seconds. Smaller black holes may also arise from the merger of neutron stars or through the collision of black holes. These mergers create larger black holes and generate gravitational waves, which are ripples in space-time.
The Sun is yellow.
False.
While there's no definitive proof, the concept of parallel universes, also known as the multiverse, is a fascinating idea explored in some scientific and philosophical theories.
How do scientists calculate the mass of a supermassive black hole?
Scientists calculate the mass of supermassive black holes by observing the motion of stars and gas in the galaxies they reside in. The faster these objects move around the black hole, the more massive the black hole is inferred to be. This is based on the principles of gravity, which dictate that a larger mass exerts a stronger gravitational pull, causing orbiting objects to move faster.
Mars is red. (simple)
True
While it's impossible to say definitively, current scientific understanding suggests the universe will likely continue expanding and cooling, potentially reaching a state of "heat death" or "Big Freeze" where it becomes too cold and dilute to sustain life, but may not technically "end". Some theories also propose scenarios like a "Big Rip" or a "Big Crunch" followed by a "Big Bounce," suggesting different potential fates.