Venus is Earth’s sister planet. It has almost the same size and gravity as Earth.
As you know, the Venus atmosphere is extremely harsh. So bleeding into space would be one way to make the planet more friendly to people.
The one big thing about Venus is that it’s atmosphere is way thicker than Earth’s. There’s no known technology that could somehow siphon all the air from Venus and send it adrift in space anymore than we could siphon all our CO2 on Earth into space.
This is a great question, but unfortunately no one will be able to give a definitive answer as to the chances.
This is simply because we do not yet know if life exists anywhere other than Earth. It is still within the realm of possibility that Earth is the only place where any kind of life, what to speak sentient life, exists.
Finding such life would be an affront to many religions that contend that God created life on Earth only, and therefore finding even a fossil of a microbe on another celestial body would be the holy grail of science and have reverberating effects throughout human society. The theory of evolution would be proven.
It is believed to be highly likely that life does exist elsewhere in the universe simply by the laws of probability, but that being said, we have found no evidence to support this theory.
So now we can come back to your original question: “What are the chances of two planets from the same solar system having sentient species that reach space exploration around the same time?” Based on the fact that life has not been discovered anywhere, the chances to sentient life forms existing in the same solar system is practically nil (but not impossible).
Since GPS achieved Fully Operational Capability on July 17, 1995, GPS has become an essential navigational tool for civilians and military alike. Keeping the system up-to-date has proved to be a problem. Originally the system was supposed to be up and running in February of 2016 but has been delayed at least until 2023.
The latest iteration of the GPS satellite array is called GPS Block III. These satellites must be launched (and will greatly increase navigational accuracy) in order to keep the Navstar global positioning system operational.
The satellites have already been built by Lockheed-Martin and consist of ten new, advanced satellites to be launched into orbit by SpaceX Falcon rockets. The hold up is the U.S. government wanting to make sure the hardware actually gets up there as they independently seek to confirm the safety and reliability of the SpaceX rocket systems.
The new GPS satellites will boost additional easier to track signals for civilian navigational uses and a Military code (M-1) providing anti-jamming security use for the military.
It just moves forward. The moon isn’t stationary. It has inertia and no atmosphere in space to slow it down. It just goes. As it moves forward, the gravity of Earth tugs on it and it falls, but because it’s moving forward it misses Earth as it falls and goes around, again and again. That’s called an orbit.
I don’t know the answer to your question. However, consider this. We are not standing still. In time the Earth rotates around it’s axis, the Earth also rotates around the sun, the sun rotates around the galactic center and the galaxy is merging with Andromeda.
We are therefore moving at hundreds of thousands of miles per hour in space. Fast forward 10 seconds and you will find yourself in outer-space without a spacesuit!
Hypothetically, we are living in an infinite universe. How far is a “near planet?”
If the planet is within a very close 200–300 light years, then there might be some possibility, within 200–300 years, that we might detect each other. If the life form is on the other side of the Milky-way, or in another galaxy, then there is no possibility.