Subjects we have to know to understand:
- Mass : in physics, the amount of substance that something contains;
- Gravity : NATURAL FORCE: the force that makes objects fall to the ground or that pulls objects towards a planet or other body;
- Escape Velocity : It is commonly described as the speed needed to “break free” from a gravitational field;
- Light : we see only what light allow us.
- Every objects has mass;
- Different objects have different quantity of mass;
- We can touch things because of the mass on its;
Ex: If we catch 1kg of gold and 1kg of cotton, we know both have the same quantity of mass but different volume. This explain us the mass can be more compact in one object then on the other.
Mass don`t tell us the space of something, only the amount of substance that it contains.
The attraction between one object with mass to another object with mass.
It`s the reason why objects fall down or Earth orbit the Sun.
Different quantity of mass has different power of attraction.
Speed needed to escape from power gravity.
On Earth, this escape velocity is 11Km/s (7 miles/s).
It`s interesting to know, the fastest velocity we had is the velocity of light (300.000 Km/s). It`s the distance light covers in one second.
We can see things because of its light or the light it reflect. We can see stars because of its lights and planets because of reflect of light on it.
Without light we can`t see anything.
Black Holes are space objects with too compact mass, too power gravity and high escape velocity.
- If we catch 1 cm3 of mass from Black Hole, this represent the quantity of Earth`s mass;
- The escape velocity is more than 300.000 Km/s;
So, the light produced by this object can`t escape to the universe and lights from other stars can`t be reflected either. Because of that, we can`t see Black Holes.