If the solar system ran into a gas cloud like the one that is thought to have started the solar system, what happens. Would the sun grow more then 2x it’s mass or the cloud be blown away by the solar wind and never enter the solar system? Would the planets and atmospheres enlarge, and rings form? How long would it take for the effects to happen if they do?
Assuming the cloud hasn’t collapsed to the point of forming a star, the solar wind will just push the stuff out of the way. The heliopause will compress some, but that won’t affect what happens on the planets.
Dense cloud of gas is a relative term in interstellar space. The atmosphere of the moon (basically none) is dense compared to that. We wouldn’t notice it. Solar wind (particles) and light pressure would sweep anything away before it got close.
It’s my understanding that it could greatly compress the “heliosphere”, potentially causing all sorts of effects.
We try and communicate with it?
The Black Cloud by Fred Hoyle
It’s vaguely possible that we’ve learned more about astronomy since 1996.
Has OP seen any heading this way?
I hope the OP hasn’t seen any in this neighborhood, since astronomers have not.
The sun seems to be near the edge of a Local Interstellar Cloud and heading toward the G-Cloud, which Alpha Centauri and other stars currently reside in. Neither of these have anywhere near the density of a nebula that’s going to collapse to a protostar. In fact, they are within in a larger low-density cavity in the interstellar medium called the Local Bubble.