How often do all of the planets repeat their exact positions? For example, how often would the planets be just as they were on any given date/time, like a birthday or historic event?

by Wayne Boyd Studied Physics (college major) & Psychology (college major) at St. Mary’s University, San Antonio, TX

You see, each planet orbits the sun at different speeds. Those planets orbiting closest to the sun, like Mercury and Venus, orbit faster. Further out from Earth, Mars takes about 2 years to orbit the sun. Further out, Jupiter, Saturn, Uranus and Neptune all take progressively longer. Then the sun itself is orbiting the galactic center once every 250 million years, and the Milky Way galaxy is moving toward the Andromeda Galaxy at about 67 miles per second. So no planet will ever be in the exact position it was before, ever. The first image shows the planets orbiting the sun in relationship to our own solar system. The second image shows the planets orbiting our sun in relationship to the sun orbiting the galactic center of the Milky Way Galaxy.

Is anybody out there?

In fact, had a giant asteroid not killed off the dinosaurs, homo sapiens might never have evolved. If it weren’t for that chance cataclysmic encounter from space, Earth might even now be ruled by dinosaurs.

By Wayne Boyd

In the early days of Hollywood and television, we used to think that life on other planets was common. Science fiction movies about invasions from the planet Mars or Venus were normal. HG Wells wrote War of the Worlds which later became a radio show and still later several big screen adaptations and it was about Martians invading Earth.

Even as our imagination thrived our knowledge of the cosmos grew. We sent probes and rovers throughout the solar system and beyond. We gazed into the stars with our space telescopes. We took images from non-visible light and radio waves. Great minds like Einstein and Hawking churned it over. Finally, after all that, we came to a startling if not disappointing realization: Planets other than Earth that support life, if they exist at all, appear to be the exception rather than the rule. There is no warmongering Martian civilization waiting to invade Earth. There are no lovely ladies lounging around on Venus. It’s true not only for our own solar system, but for all the exoplanets we’ve detected so far.

Our understanding of distances in space developed, especially between stars. Distances, it turned out, were vast. The more we knew the less likely it seemed anyone would go star hopping. That not only applies to us, but the aliens as well, if any extraterrestrial sentient beings exist at all! There will be no warp drives, no faster than light travel, and no light speed travel. It just isn’t possible. We can’t go there and they can’t come here.

Recently, there’s been some reports of UFOs in the news, and that’s always been there from the 1950s on. There is no evidence that unidentified flying objects are extraterrestrial in origin. It is unlikely for the simple reason that to travel from one star to the next would take tens of thousands of years. Sadly, and perhaps fortunately, no one is traveling from star to star. The best we can hope for is that we can visit other planets in our own solar system. Maybe one of them might at least have some microbes.

Once we figured out that there wasn’t much chance of advanced, intelligent life elsewhere within our own solar system, then we hoped we would find it on planets around other stars. Remember the movie Avatar? Supposedly that took place around Alpha Centauri, one of our closest group of stars. So if we can’t find life here then for sure it’s going to be on the closest star!

Yet, as we peered into the solar systems of other stars we came to a new understanding: most planets that we’re able to detect outside of our own solar system are hostile environments. There’s something weird about almost all of them, and so the prospect of finding life orbiting on a planet near our closest star is kind of unlikely. There’s no “Avatar” on Alpha Centauri.

Intelligent alien life is not impossible. The universe is a big place. The point is that we now know it to be rare. So rare, in fact, that it might exist nowhere other than here. At least as far as we can see so far.

In fact, had a giant asteroid not killed off the dinosaurs, homo sapiens might never have evolved. If it weren’t for that chance cataclysmic encounter from space, Earth might even now be ruled by dinosaurs.

Therefore, even if a planet were in an ideal goldilocks region around it’s star, and even if on the off chance single cell organisms had developed there, we have no reason to suspect that a homo-erectus kind of being might have developed there.

We really could be the only ones out there.

Can we “Bleed” Venus’s atmosphere as a way to terraform it?

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.

Why should we focus our “space efforts” on Venus, instead of Mars?

Well, in my opinion we should focus on the Moon.

As for Mars vs. Venus, both have unbreathable atmospheres. Mars is very cold, hundreds of degrees below zero cold. Venus is hot, melt stuff in a few minutes hot.

Mars doesn’t have rain or surface liquid water.

Venus also doesn’t have liquid water on the surface, but it does rain. The problem is it’s raining sulfuric acid.

Any probes we’ve tried sending to Venus have become dysfunctional within minutes.

How many satellites are there, and which are there on each planet?

If you count all the little nuts, bolts, loose wrenches and pieces of demolished satellites as satellites, then there’s a whole lot of junk floating around Earth. Thousands of pieces that pose a hazard.
spacejunk

Around the moon we have about three functioning spacecraft but have launched far more than that that have, over time, gone dead – perhaps crashed to the surface of the moon. Then we have the odd Juno spacecraft around Jupiter, the voyagers I and II and so on. We’ve put more space junk up there then anything else. This is a fairly accurate artist’s rendition of space junk around Earth.

The Russians have put several probes on Venus, the Americans and Europeans put a probe on Titan, we have probes on Mars, we flew a probe by Pluto and orbited Saturn for a long while before crashing deliberately. We presently have, as mentioned, the Juno spacecraft around Jupiter. We have hundreds of functioning satellites in orbit around Earth.

What would happen if NASA had the U.S. Military's budget?

We spend 600 billion dollars every year on the military. What would happen if NASA had that kind of money? Here’s a very cool YouTube video that I love to watch!
[youtube https://www.youtube.com/watch?v=chLOgj8xjx8&w=854&h=480]

Perhaps human race's home was not Earth in the first place, but in another planet, and we came here to prevent extinction

Mechanical, intentional interstellar travel is unlikely since the distances are far too great to imagine. The best anyone could achieve is interplanetary travel within one’s own solar system. Therefore, if we pass the buck and say life didn’t start here but started somewhere else and arrived here, it would have had to arrive on a rock or asteroid as a microbe and somehow survive a fiery entry through Earth’s atmosphere and it would have had to survive the vacuum and temperature extremes of space. If the rock came from outside the solar system it would have had to survive a long, long time.