For distances to other parts of the Milky Way Galaxy (or even further), astronomers use units of the light-year or the parsec . The light-year we have already defined. The parsec is equal to 3.3 light-years. Using the light-year, we can say that : The Crab supernova remnant is about 4,000 light-years away. The Milky Way Galaxy is about 150,000 ...

A light year is equal to 9,500,000,000,000 km and is the distance that light travels in one year. A light year can be expressed as 9.5 trillion km or in scientific notation as 9.5 x 10 12 km. The star outside of our solar system that is closest to Earth is Alpha Centauri C. It is 40,000,000,000,000 (40 trillion) km away. How many light years is ...

The nearest star (after our Sun, of course!) is Proxima Centauri at a distance of 4.2 light years. At a speed of 17 km/sec (such as what the Voyager 1 spacecraft currently has), it would take about 75,000 years to reach Proxima Centauri. This may explain why …

Stars, dust, and gas fan out from the center of the Galaxy in long spiraling arms. The Milky Way is approximately 100,000 light-years in diameter. Our solar system is 26,000 light-years from the center of the Galaxy. All objects in the Galaxy revolve around the Galaxy's center. It takes 250 million years for our Sun to pull us through one ...

Long ago, people believed many weird things about the Sun and how it traveled across the sky. The ancient Greeks believed that the Sun rode across the sky in a chariot drawn by four white horses driven by the god Heleius! These days, we know that the Sun appears to move across the sky because the Earth rotates on its axis.

StarChild Question of the Month for November 1998 Question: What are the phases of the Moon? Answer: The Moon orbits Earth at an average distance of 382,400 kilometers.

What is a light-year and how is it used? [March 2000] What is meant by "false color"? [April 2000] What is the biggest star we know? [May 2000] What is space trash? [June 2000] Why does the United States spend so much money on satellites? [July 2000] How do we search for alien life in the universe? [August 2000]

Gamma-ray bursts (GRBs) can release more energy in 10 seconds than the Sun will emit in its entire 10 billion-year lifetime! In order to understand what a gamma-ray burst is, you must recognize gamma-rays as the most energetic form of light. Light, or electromagnetic radiation, can be thought of as coming in tiny packets of energy called photons.

This paper contained two hypotheses. The first stated that the laws of physics had to have the same form in any frame of reference. The second hypothesis stated that the speed of light was a constant. Later that year Einstein also showed how mass and energy were equivalent. Following an impressive few years of work, Einstein became a lecturer ...

Pluto was discovered by astronomer Clyde Tombaugh in 1930. A 9th planet had been looked for for some time. It was believed that such a planet had to exist in order to explain some odd things happening in the orbits of Uranus and Neptune.