Astronomy and Cosmology

The Milky Way galaxy is estimated to be approximately 100,000 light-years in diameter.

Our galaxy is known as the Milky Way.

The supermassive black hole at the center of the Milky Way, Sagittarius A*, is the most massive object in our galaxy.

Astronomical observations confirm that a supermassive black hole, known as Sagittarius A*, resides at the center of the Milky Way galaxy.

The solar system is located within the Milky Way galaxy.

A constellation is a group of stars that form a recognizable pattern in the night sky. The other options refer to different celestial objects or forces.

A star is a massive, luminous sphere of plasma held together by gravity. It produces energy through nuclear fusion, which we perceive as heat and light.

A comet is a small solar system body that orbits the sun and, when close enough, exhibits a visible coma or tail due to solar radiation. It is composed of ice, dust, and rock.

A telescope is an optical instrument designed to make distant objects appear closer and larger by gathering light. The other options are celestial bodies or physical forces.

A planet is a large celestial body that orbits a star, is spherical due to its own gravity, and has cleared its orbital path. The other options do not fit this definition.

Supergiants are the largest stars in the universe in terms of physical volume. They are significantly larger than red giants, white dwarfs, or blue giants.

Scientific estimates for the number of stars in the Milky Way galaxy typically range between 100 billion and 400 billion. 200 billion is the most widely accepted average estimate.

Stars are primarily composed of hot gas, specifically hydrogen and helium, held together by gravity. The extreme pressure and heat cause nuclear fusion in their cores.

Proxima Centauri is the closest star to our solar system, located about 4.24 light-years away. It is part of the Alpha Centauri star system.

Our solar system is located within the Milky Way galaxy. It is a barred spiral galaxy.