Yes we know it does exist.
You should be as honest as Nasa to answer my question.
We don't really know. We can define what it is as a field of influence, because we know how it operates in the universe. And some scientists think that it is made up of particles called gravitons which travel at the speed of light. However, if we are to be honest, we do not know what gravity "is" in any fundamental way - we only know how it behaves.
What is gravity?
General relatively shows that nothing or that which is not seen or the invisible or the eternal Spirit controls everything and creates everything and holds everything together.
That eternal Spirit is the invisible with substance.
Everything physical is created and comes from from eternal Spirit or nothingness.
Just like our spirit/consciousness/minds are "nothing" and "invisible" and "eternal" with substance. Empty space between everything.
This "nothing" or "invisible" or "eternal" is infinite and indestructible.
Nothing ...is really something and causes everything to happen.
People, mankind/mindkind are living as their false, mortal mind-self, and they should be living as their immortal spiritual-self, the exact opposite of the way they are now. If you are completely open, life fills the void completely. All life comes to one, it is given to one by God/life. One is just a receiver. Living it and reflecting what we receive. Life moves around and through one. When one is completely open, nothing is completely displaced with everything.
Every physical thing has so much empty space in it, including our bodies.
If you removed all the empty space from human bodies leaving only electrons and the other subatomic particles, all billions of human bodies combined would fit in the space of a sugar cube.
In the dark realm of nothingness lies the greatest light.
The science that is trying to explain everything mathematically, is a unified field equation. It would explain why everything physical does what it does in a mathematical equation. They have not been able to do it, but they have not been considering the field or tried to add it to the equation. The field is what we call nothing (life/consciousness/spirit)
It's silly when one, being conscious themselves is trying to understand the universe apart from consciousness.