科学普及出版社英语书八年级上册第十页课文

1. The fairy system is the closest system to the Milky Way, with only 2.9 million light-years. Slightly larger, similar elements, spiral shape. If a spacecraft lifts off from Earth to the fairy at (near) the speed of light.(Although this requires huge energy and therefore almost impossible) Starting from 2018,290 until 2018. This is already the fastest speed in physics. This is already the most recent galaxy. According to the relativistic effect, the time on the ship slows down, and when reaching the fairy system, the ship is set back in 2059.

2. What is a quasar? At the known edge of the universe, 12 billion light-years away, there is a huge star. A point of light can still be seen on the Earth's light microscope. What exactly is it? We don't know that as yet. One guess is that these are massive black holes. And this light came from 12 billion years ago, when the universe was born.

The uncertainty of quantum theory, may be the truth of the universe. Our common sense holds that the material world should be clearly defined, one, one and two. However, the

probability wave of quantum theory suggests that perhaps uncertainty is the nature of the universe. Chaos and probability waves of the universe are the norm. And certainty is a transient state. The visible world we humans is also transient.

4. In general relativity, or in higher dimensions, gravity does not exist. Body mass causes the bending of the space. The surrounding objects will then move along the curved shortest path. This is true, from galaxies to comets. This is a mathematical phenomenon.

5. Dark matter. From Newton's second law, the mass of the Milky Way is far from the matter we see. There is still at least 10 times the visible mass, not yet visible and undetectable. This is the dark matter. This could be a yet undiscovered particle, or some yet undiscovered black hole.