The Andromeda Galaxy is a neighboring galaxy of the Milky Way, about 2.5 million light-years away

Image: Boris Stromar / CC BY-SA 3.0

Stars and Galaxies

How beautiful a cloudless night sky is. It is dotted with points of light, some shining brightly, others only faintly; all are outshone by the moon. These points of light are stars. People have always looked up at them and imagined all sorts of things about them. They saw constellations in certain arrangements, such as Aquarius or Libra. People believed these constellations influenced their lives, and astrologers claimed they could read the future in them.


Modern science does not put much stock in this. We know that we can see about 6,000 stars with the naked eye. Most seem fixed in their positions, which is why they used to be called fixed stars. Others, however, noticeably changed their positions and were known as wandering stars.


We now know that these wandering stars are not stars at all. They are planets in our solar system, moving around the Sun in orbits just like Earth. They shine only because sunlight illuminates them and they reflect the light. Fixed stars, on the other hand, are suns like ours. Some are even larger, but they are all much farther away.


We also know that the suns in space form groups together with other stars. We call these groups of stars galaxies. Our Sun belongs to a galaxy called the Milky Way. It contains at least 100 billion stars, though it may have as many as 400 billion.


The Andromeda Galaxy is the galaxy closest to the Milky Way. Even so, it is about 2.5 million light-years away. The two galaxies are moving toward each other and will collide in about 3 to 4 billion years, forming a new, larger star cluster.


The Milky Way and the Andromeda Nebula are just two of countless galaxies. With the technology available to us today, we can detect more than 50 billion galaxies. Scientists now estimate that there are about one trillion galaxies in the universe.


This staggering number may help us understand that humans and our Earth are by no means the center of the universe and creation, but merely lost specks of dust in an immeasurably vast expanse.

✍️ Galaxies

  1. With the naked eye, we can see about ____ stars.
  2. The stars once known as wandering stars are actually ____.
  3. Planets only shine because they are ____ by a star.
  4. A ____ consists of countless stars.
  5. The galaxy our Sun belongs to is called the ____.
  6. This star cluster contains at least ____, but perhaps as many as ____ stars.
  7. The galaxy closest to the Milky Way is called ____.
  8. It is about ____ light-years away.
  9. In ____ the two galaxies will collide and gradually merge.
  10. Scientists estimate that there are about ____ galaxies in the universe.

Complete the sentences and write out the text.

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