Mada za sehemu hiiElementary AstronomyMada 4
The solar system is made up of the sun and the celestial objects bound to it by gravity. These objects include the eight planets and their known moons and billions of small bodies that include asteroids, comets, meteoroids and interplanetary dust.
A star is a large celestial body made up of hot gases known as plasma.
Plasma is an ionized gas in which a certain proportion of electrons are free rather than bound to an atom or molecule.
The sun is a large star. The sun is also the closest star to the earth. Astronomical unit is the distance between the earth and the sun, which is used to measure distances across the solar system (its value is approximately 149.60 million kilometers).
A Galaxy is a giant collection of stars, gas and dust.
Planet is a major (large) object, which is in orbit around a star.
There are eight planets, which are
- Mercury
- Venus
- Earth
- Mars
- Jupiter
- Saturn
- Uranus
- A celestial body orbits a star.
- It is massive enough so that its own gravity cause it to assume a spherical shape.
- It has cleared the neighborhood around its orbit.
| Stars | Planets |
|---|---|
| Emit their own light | Do not emit their own light |
| Twinkle at night | Do not twinkle at night |
| Appear to be moving from east to west. | Planets move around the sun from west to east. |
| Their temperatures are usually very high | Their temperature depends on their distances from the sun |
| Countless in number | There are eight in the solar system |
| Very big in size but they appear small because they are very far away | Very small in size as compared to stars. |
Asteroids are small solar system bodies in orbit around the sun, especially in the inner solar system. Asteroids are smaller than planets but larger than a speck of dust.
A comet is a solid body orbiting the sun typically composed of rock dust or ice. Most comets were formed from condensed interstellar gas and dust clouds in the early stages of the creation of the universe.
Gravitation force is the attractive force existing between any two objects that have mass. It pulls objects together and acts on all matter on the universe.
States that: "Every single point mass attracts every other point by a force directed along the line joining the two masses". The force is proportional to the product of the two masses and inversely proportional to the square of the distance between the point masses.
Where:
- is the magnitude of the attractive force between the two point masses.
- is the universal gravitation constant.
- is the mass of the first point mass.
- is the mass of the second point mass.
- is the distance between the centers of the two point masses.
Gravity is the gravitational force that occurs between the earth and the other objects. It pulls the objects towards the center of the earth. It holds us on the ground and causes objects to fall back to the ground after being thrown out in the air.
Mwalimu
Unasoma somo hili? Niulize nikuelezee chochote kilichomo.
Ingia ili kumuuliza Mwalimu wa AI wa Sonza kuhusu mada hii.
Ingia ili kuuliza