Space Debris – A Dodging Problem

This is a no frill video (no audio) produced by scientists, to depict just how much junk “litter” we have floating around up in space, some of it going 35,000 miles per hour.

Just something to think about.

Which is more difficult to achieve 100 years from now, building a giant telescope to directly observe other planets in a distant Galaxy or building a faster than light space ship?

Faster than light speed will never be possible, ever. The best you’ll be able to do is maybe 1/10th the speed of light given an enormous amount of propellant, and then you’ll have to slow down at the end of the trip using just as much fuel as it took you to go that fast in the first place. There will be no warp drive or something that folds space. These are all convenience devices for story telling on science fiction movies.

Maybe in 200 or 300 years generational space environments will be the way to travel to other planetary systems. A generational space environment is a huge ship that rotates for a sense of gravity inside, where whole generations are born and die over hundreds of years – often resenting that their ancestors trapped them on that ship – to reach far away places.

Your given time frame of 100 years from now is not very far away in the bigger picture, but having a huge telescope on the far side of the moon is possible and would help with astronomical observations.

If two ships are travelling side be side at some major fraction of the speed of light (e.g. 90%) and are, say, 100 yards apart, would they be able to see each other out the portholes?

Great question, and you see, that’s what we mean when we say everything is relative. Your “speed” is always relative to something else. If you don’t compare it to something else, you might as well be standing still.

Relative to you, the other spaceship is standing still. You are both just floating there while Earth quickly moves away from you.

If you were going 90% the speed of light relative to your launching site on Earth, then if you looked back at Earth through a telescope you’d see them all aging very quickly, but to you and your neighboring spaceship, you’d both not experience any personal change. You’d be able to see the other ship and vice versa quite normally.

In fact, if you took a flashlight and pointed it straight ahead in the direction of your travel, even though you were going 90% the speed of light relative to Earth, the beam of light would leave your flashlight at the speed of light relative to you. That’s only possible because time has slowed down for you, making light always look like it’s going light speed. You will not notice any change personally.

On Earth, people looking at you in a telescope would see you were moving and aging very slowly, and although the light of your flashlight would not appear to be going much faster than your spaceship, because your time has slowed down, you see it going out at the speed of light and people on Earth are moving slowly.

Consider this. Here you stand or sit. But the earth is spinning at about 1000 mph at the equator. We are also going around the sun at about 67,000 mph and orbiting the galactic center of the Milky Way galaxy at about 514,000 mph, and our galaxy is approaching the Andromeda Galaxy at about 250,000 mph. So you are not standing or sitting still at all! You are moving very fast right now, but when you shine a flashlight in all directions the beam leaves your flashlight at the speed of light relative to you and your sense of time.

The same happens to you and your friend in the nearby spaceship. You can look out the porthole, see him, and wave and he can see you and wave back as if both your ships were stationary in space and just floating next to each other. It’s all relative.

On what planet should we build the first non-Earth city?

I know. It’s sad. Depressing really. Humans will never build a city off our planet Earth.

I say this because of distances. Even if we were to find a planetary candidate, it would take hundreds or thousands or more years to go one way to visit it just to see if the candidate is really like we need, what to speak of building a city.

Distances in space are unimaginably big. Let’s say the nearest star is 4 light years away. There is no guarantee there is life over there, but to travel that 4 light years will not take 4 years, or 40 years. At the fastest speed ever achieved it would take at least 150 years each way.

Suppose we wanted to take a closer look at the Trappist-1 system, 40 light years away. It is the next best candidate for life. That would take a mere 1,500 to 2,000 years to go one way just to see if anything really was habitable, what to speak of building a city.

Sadly, this is indeed science fiction. We want it to happen, so badly, but it never will happen. At most we might leave some foot prints on Mars and send some robotic systems to the moons of Jupiter and Saturn, but that’s it. Long before our sun blows up, life on Earth will be extinguished.

How many earth years would it take to travel to the sun?

The New Horizons space craft set a record at 36,000 miles per hour, the fastest spaceship relative to Earth ever achieved. The sun is 94 million miles away, so if you divide 94 million by 36,000 mph you come up with 2666.67 hours, or 111.111 days. That’s about 3 months and 21 days, round out to 4 months to be safe.

However, you can’t just launch a space ship from Earth directly at the sun and expect to go 36,000 mph. New Horizon’s speed was achieved through slinging around planets, what we call “gravity assist.” Your sun bound space craft would begin slowly and take a very long time to reach the sun.

If it took the Apollo astronauts 3 days to go 250,000 miles to the moon. At that speed it would take just over 3 years to reach the sun.