Question

1. which of the above modeled the universe as a series of spheres in which earth was the central sphere?
2. who was the first to represent the sun as the center of our solar system, but did so anonymously for fear of being branded a heretic by the church?
3. who was the first to contribute to this

ew\ idea by using the moons of jupiter as reference?

1. who was the first to name the actual force responsible for the orbits of the planets around the sun?
2. what did he call this force?
3. true or false: to have gravity something simply needs to have mass.
4. how can light move so fast?
5. explain what orbit really means:
6. if there is an edge to our universe, why cant we see it?
7. how long does it take for our sun to make one revolution around the center of our galaxy?
8. how big is our galaxy in light years across?
9. define light year:
10. explain what the cosmic microwave background radiation is:
11. what makes red light and blue light different colors?

Explanation:

1. Ptolemy modeled the universe as a series of spheres with Earth as the central sphere in his geocentric model.
2. Nicolaus Copernicus was the first to represent the Sun as the center of the solar - system anonymously for fear of being branded a heretic.
3. Galileo Galilei used the moons of Jupiter as evidence to support the heliocentric model.
4. Isaac Newton was the first to name the actual force responsible for the orbits of the planets around the sun.
5. He called this force gravity.
6. True. According to Newton's law of universal gravitation, any two objects with mass attract each other with a gravitational force.
7. Light moves so fast because it is an electromagnetic wave and in a vacuum, it has no medium - related resistance and travels at a constant speed ($c = 299792458$ m/s) due to the nature of electromagnetic fields.
8. An orbit is the curved path of an object (such as a planet, moon, or satellite) around a larger object (such as a star or planet) due to the gravitational force between them.
9. If there is an edge to the universe, we can't see it because the light from the edge may not have had enough time to reach us since the universe is expanding and the light has a finite speed. Also, the universe may be curved in such a way that there is no "edge" in the traditional sense.
10. It takes about 225 - 250 million years for the Sun to make one revolution around the center of our galaxy.
11. Our galaxy, the Milky Way, is about 100,000 - 120,000 light - years across.
12. A light - year is the distance that light travels in one year in a vacuum. Since light travels at a speed of approximately 299792458 m/s, in one year (31536000 s), it travels about $9.461\times10^{15}$ meters.
13. Cosmic Microwave Background Radiation (CMB) is the afterglow of the Big Bang. It is a nearly uniform electromagnetic radiation filling all of space, with a temperature of about 2.725 K. It is the oldest light in the universe, dating back to about 380,000 years after the Big Bang when the universe became transparent to light.
14. Red light and blue light are different colors because they have different wavelengths. Red light has a longer wavelength (around 620 - 750 nm) compared to blue light (around 450 - 495 nm). Different wavelengths are perceived as different colors by our eyes and brain.

Answer:

1. Ptolemy
2. Nicolaus Copernicus
3. Galileo Galilei
4. Isaac Newton
5. Gravity
6. True
7. It is an electromagnetic wave with no medium - related resistance in a vacuum and travels at a constant speed due to the nature of electromagnetic fields.
8. The curved path of an object around a larger object due to gravitational force.
9. The light from the edge may not have reached us yet due to the finite speed of light and the expansion of the universe, and the universe may be curved.
10. About 225 - 250 million years
11. About 100,000 - 120,000 light - years
12. The distance that light travels in one year in a vacuum (about $9.461\times10^{15}$ meters).
13. The afterglow of the Big Bang, a nearly uniform electromagnetic radiation filling all of space with a temperature of about 2.725 K.
14. They have different wavelengths (red light has a longer wavelength than blue light).