Is It Possible to Detect Gravity with Our Eyes Without Using Instruments Like LIGO and Gravitational Waves?

Yes, drop something and watch it fall. Note that gravity and gravitational waves are different things. Gravity is everywhere, and observing it directly with your eyes is something that most of us can do without needing any special instruments like LIGO (Laser Interferometer Gravitational-Wave Observatory).

Gravity and Gravitational Waves

Indeed, it is possible to detect gravity using your naked eyes. Just observe an object being dropped and watch it fall. This is direct evidence of gravity in action. However, it is important to note that gravity and gravitational waves are distinct phenomena. While gravity refers to the force that attracts a body toward the center of the earth or another massive body, gravitational waves are ripples in spacetime caused by some of the most violent and energetic processes in the Universe, such as the collision of black holes or the merging of neutron stars.

Strength and Detection of Gravitational Waves

Einstein's theory in the weak field limit proposes that gravity behaves like waves. In this context, gravitational waves are extremely subtle, and their detection requires highly sensitive instruments. For example, the strain caused by a gravity wave from a neutron star merger occurring billions of light-years away would be on the order of (10^{-21}). This is roughly equivalent to the ratio of the width of an atom to the diameter of the Earth’s orbit around the Sun.

This level of precision cannot be observed with the naked eye. While you can detect the gravitational pull of an object by observing it fall, detecting gravitational waves requires instruments capable of measuring infinitesimally small distortions in spacetime.

Feeling the Effect of Gravity

While gravity can be detected visually, the effect is also non-visual. An experiment can demonstrate this. Pick up a heavy object, such as a sledgehammer or a large stone, and hold it at shoulder height directly above your right big toe. Be sure to remove your shoes and socks to ensure direct contact.

When you drop the object, gravity will exert its force on the object, causing it to fall towards the Earth. However, the indirect effect of gravity can also be felt. About half a second after the object is released, you will experience a subtle force. This force is a manifestation of gravity, even though you are not seeing it visually.

This is just one way to experience gravity non-visually. The force of gravity affects everything around us, from the smallest atoms to the largest celestial bodies. Understanding this force is fundamental to our comprehension of both everyday experiences and the extreme phenomena in the universe.