Well I said Mars could be our history but not our future in terms of a large life-supporting human civilization. Actually our solar system in its initial days was a large gaseous cloud circling around the Sun, while cooling down slowly, it started solidifying and formed thousands of small planets, which further started clubbing together as the bigger ones started attracting the smaller ones, some bigger planets became so big that some smaller planets started circling around the bigger planets instead of the Sun because of the large planets gravitational forces coupled with close proximity (Moon was probably created in a different manner though). So this is how our solar system came to its present form.
Now all were hot gaseous planets in the beginning, but they were cooling down and some planets started forming a solid crust on the top known as soil. but the core was/is still hot liquid. Now the interesting part; you know what makes the Earth habitable? It's the core, the core is primarily iron and other hot liquid metal always spinning and generating a force known as gravitation, this gravitational force is holding the layer of gases around the Earth broadly known as Atmosphere, this layer of gases are responsible for protecting our Earth from the extremely deadly solar radiation of the Sun, without this shield Sun would wipe out our climates, water, and all life forms, think of it like a gigantic microwave oven.
Now Mars once had water on surface, rivers and all just like Earth, definitely it also had an atmosphere, hence, life was not impossible on Mars. Since Mars was further from Sun than Earth, it cooled down and became life-supporting much earlier than Earth, so, if Mars ever had life, it had to predate Earth's. Now there is a possibility, a theory, that life on Mars evolved and became intelligent, when the understood that Mars is dying, probably they seeded the Earth with life. Or maybe, by that time life came to Earth also, but Martians seeded it with a more advanced form of life, i.e. human, to survive their species! Maybe our origin is Mars, maybe our gods were Martians!! Sometimes don't you feel we humans are kind of odd, misfit, out of the world, compared to all other life forms on this planet?
Now, how Mars died? Well, it was a much smaller planet than Earth, hence, it cooled down faster, the liquid core became cold & solid, gravitational force was gone, so was the atmosphere, and Mars got cooked in the solar microwave! Our Earth will die the same way, unless it is hit by a large asteroid earlier than that, or we nuke it.
And no, we are not going close to Sun, Venus has no hope to sustain life as it is too close to sun, Mars cannot sustain life on its own anymore, and 2050 is a ridiculously close timeline, one should think in millions or billions of years in these matters. In fact, when the Sun will be dying, it will start expanding and eating up all the planets in its solar system, finally it will blast away. Stars that are much bigger than Sun start crumbling under their own weight and become Blackholes with gravitational force that even light can't escape.
btw, do you wear gold or platinum jewelry? look at them closely, those heavy metals didn't form on Earth, they formed in the core of a dying star, a star like our Sun, and then they came to Earth through space debris like asteroids!! Amazing??
Any way yes we can never reach speed of light unless you cease to exist/become imaginary. If you cross the speed of light you cease to exist for this world. Clearly from the equation:
