The Space Quiz: How Well You Know?

Gravity is the force that holds a galaxy together. It is the force of attraction between all objects with mass, and it plays a crucial role in the formation and structure of galaxies. The gravitational pull between stars, planets, and other celestial bodies within a galaxy keeps them bound together, preventing them from drifting apart. Without gravity, galaxies would not be able to maintain their shape and structure, and the stars and planets within them would disperse into space.

When a star dies, it undergoes a supernova. A supernova is a powerful explosion that occurs when a massive star exhausts its nuclear fuel and collapses under its own gravity. This explosion releases an enormous amount of energy and results in the ejection of outer layers of the star into space. The remaining core may collapse further to form a neutron star or a black hole. Therefore, the correct answer is "Supernova."

Stars explode because they run out of fuel. As a star burns its fuel, it produces energy through nuclear fusion. This energy counterbalances the gravitational force pulling the star inward. However, once the fuel is depleted, there is no longer enough energy to counteract gravity, causing the star to collapse inward. This collapse can trigger a massive explosion known as a supernova, releasing an enormous amount of energy and creating heavy elements in the process.

Galaxies come in various sizes, meaning that some are big while others are small. This is due to factors such as the amount of matter and the rate of star formation within each galaxy. Therefore, the statement "Some galaxies are big, some are small" accurately describes the size diversity among galaxies.

A red dwarf star is the smallest star. Red dwarf stars are small and cool compared to other types of stars, such as neutron stars and Porto stars. They have a mass less than half that of the Sun and a surface temperature of less than 4,000 Kelvin. Despite their small size, red dwarf stars are the most common type of star in the universe. They have a long lifespan, burning their fuel at a slow rate, which allows them to exist for billions of years.

The correct answer suggests that there are more stars in the universe than there are grains of sand on Earth. This implies that the number of stars is incredibly vast and exceeds the amount of sand particles on our planet.

Galaxies move thousands of miles per second. This is supported by scientific evidence that shows galaxies are constantly moving and expanding within the universe. Through observations and measurements, astronomers have determined that galaxies have a variety of motions, including rotational motion within themselves and motion relative to other galaxies. These movements are often caused by gravitational forces exerted by nearby galaxies or the overall expansion of the universe. Therefore, it can be concluded that galaxies do move at incredibly high speeds, not at a mile a month or by any other options provided.

Inside a galaxy, planets do not die and stars do not fall. Galaxies are vast systems of stars, planets, gas, and dust held together by gravity. Planets orbit around stars, and stars remain relatively stable in their positions within the galaxy. Therefore, the correct answer is "None of the above."

The Oort Cloud is theorized to be a distant spherical shell surrounding the Solar System, composed of icy bodies and fragments believed to be the source of long-period comets that occasionally enter the inner Solar System. It is named after the Dutch astronomer Jan Oort, who hypothesized its existence. The Oort Cloud is thought to extend from about 5,000 astronomical units (AU) to as far as 100,000 AU from the Sun, marking the outer edge of the Solar System's gravitational influence.

Andromeda is the closest spiral galaxy to the Milky Way. It is currently moving towards us at a speed of about 110 kilometers per second. Based on its current velocity and distance, it is estimated that it will take approximately 2 million years for Andromeda to reach us.