###### what experiment confirmed the existence of gravitational waves?

The first direct detection of gravitational waves was made by the Laser Interferometer Gravitational-Wave Observatory (LIGO) in 2015. This groundbreaking discovery confirmed a major prediction of Albert Einstein’s theory of general relativity and opened up a new field of astronomy, allowing us to study the universe in a completely new way. The detection was made by observing the minute distortions in space-time caused by the passage of a gravitational wave from the collision of two black holes over a billion light-years away. This discovery was widely regarded as one of the most important scientific breakthroughs of the century and has been recognized with several awards, including the 2017 Nobel Prize in Physics.

###### what ALL experiments have we done to detect gravitational waves?

The detection of gravitational waves has been carried out by various experiments, most notably the Laser Interferometer Gravitational-Wave Observatory (LIGO). LIGO uses laser interferometry to detect extremely small distortions in space-time caused by the passage of gravitational waves. Another experiment, the Virgo interferometer, has also detected gravitational waves. These detections have been made possible by the extremely precise measurements of the distance between mirrors, which are affected by the passing gravitational waves. The collaboration between LIGO and Virgo has allowed for more accurate localization of gravitational wave sources in the sky.

###### have we learned yet at what speed of gravitational waves travel?

The speed of gravitational waves is equal to the speed of light, approximately 299792458 meters per second. This has been confirmed by numerous experiments and observations, including the detection of gravitational waves from merging black holes and neutron star.

#### Isaac Newton

Isaac Newton discovered that all objects with mass are attracted to each other. This force of attraction is called gravity. The more mass an object has, the stronger its gravitational pull. The distance between two objects also affects the strength of the gravitational force. The farther apart two objects are, the weaker the gravitational force.

Newton’s discovery of gravity was a major breakthrough in physics. It helped to explain why objects fall to the ground, why the planets orbit the sun, and why the moon orbits the Earth. Newton’s law of universal gravitation is still used today to calculate the orbits of planets, satellites, and other objects in space.

Here is a more mathematical explanation of Newton’s law of universal gravitation:

`F = G * (m1 * m2) / r^2`

Where:

- F is the force of gravity between two objects
- G is the gravitational constant (6.67408 × 10^-11 N m^2 kg^-2)
- m1 and m2 are the masses of the two objects
- r is the distance between the centers of the two objects

Newton’s law of universal gravitation is one of the most important laws in physics. It has helped us to understand the motion of objects in the universe and has led to many advances in science and technology.

#### Albert Einstein

Albert Einstein learned that gravity is not a force, but rather a curvature of spacetime. Spacetime is the fabric of the universe, and it is made up of space and time. The presence of mass or energy curves spacetime, and this curvature is what we experience as gravity.

Einstein’s theory of general relativity is a much more comprehensive theory of gravity than Newton’s law of universal gravitation. It has been tested in many different ways, and it has always passed with flying colors. General relativity has helped us to understand many things about the universe, including the expansion of the universe, the existence of black holes, and the bending of light around massive objects.

Here are some of the things that Einstein learned about gravity:

- Gravity is not a force, but rather a curvature of spacetime.
- The more mass an object has, the more it curves spacetime.
- The curvature of spacetime is what causes objects to fall towards each other.
- The curvature of spacetime also affects the path of light.
- Black holes are regions of spacetime where the curvature is so strong that nothing, not even light, can escape.
- The expansion of the universe is caused by the curvature of spacetime.

Einstein’s theory of general relativity is one of the most important and successful theories in physics. It has helped us to understand the universe in a much deeper way, and it has led to many advances in science and technology.