If you were in a spacecraft traveling between galaxies, how would you measure your velocity?

Velocity is relative, as is everything in the universe. Relative to Earth? Relative to a nearby galaxy?

In space you are standing still. You are not moving at all.

If you see a galaxy over there you want to head toward, you apply some acceleration and over several million years it starts to get closer to you.

But your speed and your time to you always remains constant.

How are there pictures of the earth from space and from space stations from earth’s orbit, when we rotate over 1000 mph?

Why don’t you ask what is the circumference of Earth? 24,901 miles. That’s why it takes roughly 24 hours to go around one time, because it’s rotation at the equator is about 1,040.4 mph (much slower where you live further north). The International Space Station goes around the earth about every 92 minutes. A lot faster than the Earth rotates. Furthermore, the ISS is not traveling in the same direction of the Earth’s rotation, but more a north south direction.

In any case, the ISS travels faster than the Earth rotates, so you do see the Earth moving below it, but not so fast you can’t take a photo or shoot a video. Just look at the video below. Even this video is sped up. From up there, the Earth moves much slower. This is a time lapse video.

Which terrestrial planets, if terraformed, you’d like to visit or live? Is it Mercury, Venus, Moon, or Mars?

I’m going to suggest if we could terraform Earth to be a sustainable, livable planet, that would be the best use of our technology, since we’re already here. It would also prove we could do it elsewhere. Why go to Mars, Venus the Moon or Mercury when you could figure out how to take all the toxins and poisons out of our own air here on Earth?

Think about it.

You know why we don’t? Because we can’t. It’s all a scam.

Did something happen in the past that made scientists believe that aliens exist?

Well, statistically and evidentially, yes.

Statistically, there are thousands and billions of galaxies, each consisting of billions of stars, and each star generally has at least one orbiting planet, it is highly likely some form of extraterrestrial life exists out there.

Evidentially, we have seen plumes of gas coming from moons around Saturn, suggesting a warm liquid ocean underneath a sheet of ice, a good place to look.

However, and I don’t mean to burst your bubble, but to date no evidence of life anywhere else but here on Earth has ever been found. We have not even found a fossil of a microbe on a meteorite. Nada.

We believe life is out there, but we have no proof to date that life has developed anywhere in the universe other than Earth.

Using the latest technologies & maneuvers, what speeds can we hope to achieve in space flight?

I’m just wondering for practical purposes. Doesn’t even have to be a manned mission, so all that extra life support weight can be dumped. Using optimal fuel mixtures, the latest technology, & as many gravity slings & other natural phenomena as possible how fast could we go?

According to Wikipedia:

New Horizons is currently making 15.73 kilometers per second on its way to a Pluto/Charon flyby in July of 2015, impressive but not the kind of speed that would get us to interstellar probe territory. Interestingly, the fastest spacecraft ever built weren’t headed out of the Solar System at all, but in toward the Sun.

End of quote. No let’s analyze this in terms of interstellar travel. The best candidate for possible habitable planets we know nearby are part of the TRAPPIST-1 system, which has 3 planets squarely in “the habitable zone.”

This system is very, very close compared to the rest of Milky Way and the universe: Only a mere 40 light years.

Gravity swings work great inside a solar system. Out in deep space between stars with no other planets or bodies to gravity assist, you’re just going be traveling at the fastest gravity assist you could accomplish before leaving our solar system. That would be about 15.73 km/s.

Since a light year is about 5.88 trillion miles, or about 9.5 trillion killometers and one trillion equals one thousand billion, and one billion equals one thousand million, to travel 40 light years at 15.73 kilometers would take awhile. 15.73 km per second is 56,628 km per hour. So if we divide 9.5 trillion by 56,628 km it will tell us how many hours it would take to reach TRAPPIST-1. In this way, dividing that number by 24 will tell you that it would take 1,359,072 days to reach there, or about 3,723 years.

One way. To transmit back to Earth what you found would take another 40 years at the speed of light. Would anyone still be listening?

In other words, going as fast as we can, it would take three thousand seven-hundred twenty-three years to reach that system, what to speak of any other stars further away.

We’re not going to ever go there, and nobody from space is ever going to come here.