How are galaxies formed?
Galaxies are formed through a process that involves the gravitational attraction of matter in the universe. Initially, small perturbations in the density of matter caused some regions to have slightly more matter than others. These regions then attracted more matter through gravity, eventually forming stars, galaxies, and clusters of galaxies.
What is the universe expanding into?
The universe is not expanding into anything; instead, it's the space itself that is expanding. This means that every point in the universe is moving away from every other point. It's a concept that defies our everyday understanding of how things move in space.
How is dark energy measured?
Dark energy is measured indirectly through its effects on the universe's expansion. Scientists observe distant supernovae, or exploding stars, to measure how fast the universe is expanding. The unexpected discovery that the expansion is accelerating led to the concept of dark energy.
Can antimatter be created?
Yes, antimatter can be created. In fact, it's regularly produced in particle accelerators for research purposes. When a high-energy particle collides with another, the energy of the collision can be converted into mass, creating a particle and its antiparticle.
What is inside a black hole?
The interior of a black hole, known as the singularity, is a point of infinite density according to general relativity. However, the laws of physics as we currently understand them can't describe what's inside a black hole. This is one of the biggest unsolved problems in theoretical physics.
How are cosmic distances calculated?
Cosmic distances are calculated using several methods. For nearby stars, astronomers use parallax, which is the apparent shift in a star's position as Earth orbits the Sun. For more distant stars and galaxies, they use standard candles, which are objects with known brightness, like certain types of supernovae or variable stars. The observed brightness of these objects can be used to calculate their distance.