Category Archives: Astronomy

Shouldn’t we be looking for life on planets that formed over 10 billion years ago as they’ve had more time for life to form?

Planets that formed over 10 billion years ago are about 5 billion light years from us, meaning that if we could somehow study planets that far away (we can’t) the light reaching us from there would have taken 5 billion years to reach us. Therefore, we’d be seeing what the planet looked like 5 billion years ago, not what it looks like now. Below is what we are able to see of the most distant galaxy that we have seen to date. It’s about 13 billion light years and we are just seeing the early stages of development because it took light 13 billion years to reach us.

As you can see from the image, Hubble can barely make out the galaxy, what to speak of any planets that might be orbiting the billions of stars inside that galaxy. The best we can do is study planets in our vicinity of the Milky Way.

How can we believe in God, but not in alien/extraterrestrial life or vice versa? This seems like a paradox to me.

I don’t see either as being dependent on the other. In other words, you can believe in God and not in extraterrestrial life. Many religious people do in fact hold that view. On the other hand, you can believe in extraterrestrial life and not believe in God. I know many people who hold that view.

So I don’t see a paradox at all. According to the Google dictionary, a paradox is “a seemingly absurd or self-contradictory statement or proposition that when investigated or explained may prove to be well founded or true.” I fail to see a contradiction that two different people can hold either view. It’s all theory.

In reality, we do not know for sure that life exists anywhere other than Earth because we have never found any evidence of life, although we continue the search. We have yet to find even a fossil of a microbe from space. However, the laws of mathematical probability suggest that with billions of planets in this galaxy and billions of other galaxies, it is likely that there is at least microbial life somewhere, if not something more advanced. We just haven’t the proof yet.

Similarly, except for subjective experiences, there is no proof that God exists either, although people believe that God exists. Maybe both exist. Maybe neither exists. I suppose it’s a question of faith in either view.

Assuming that there were humans on Mars, how long would it take for a voice transmission from Earth to reach them? Would the times be different for other electronic forms of communication?

Transmissions from Mars to Earth and visa versa happen at the speed of light. However, Mars is sometimes near Earth and sometimes on the other side of the sun. Therefore, depending on where Mars is in relation to Earth in our orbit around the sun, transmission times change from 4 minutes to 24 minutes. If Mars is close to Earth in orbit around the sun it’s 4 minutes. If Mars is on the other side of the sun from Earth in our orbit, it’s about 24 minutes.

If an astronomer on a planet in the Galaxy MACS0647-JD (13.5 billion light years away) were to point their telescope toward our Galaxy, what would they see?

When you look into a telescope at the galaxies and stars you are looking back in time, because it took time for the light of those objects to reach you. If it took 13 billion years to get you then you’d be seeing light that originated 13 billion years ago. If you could see clearly, you’d be looking at what happened 13 billion years ago. By the time we see the MACS067-JD Galaxy, that galaxy might no longer exist.

Earth is about 4.543 billion years. Round that to 4.5 billion. Your astronomer is in the MACS0647-JD galaxy, the farthest galaxy known, which is actually about 13.3 billion light years away, so he’d see light arriving from around these parts from 13.3 billion years ago, before Earth existed, before our sun existed, and pretty much the beginnings of the Milky Way Galaxy, which itself is about 13.51 billion years old. Basically, he wouldn’t see much more than we see when we look at his galaxy. No sun, no Earth, and the Milky Way Galaxy just taking shape.

Why are we so obsessed with finding the smallest amount of life on another planet when we have amazing life that we take for granted here on Earth and we destroy it?

I don’t think this scientific quest detracts from our appreciation for all the wonderful things we have here on Earth.

You’re right. We need to do both.

However, just why are scientists “so obsessed” with “finding the smallest amount of life on another planet” in the first place, and why are people taking life for granted here on Earth and destroying it?

First, the searching for life in space boils down to an ancient feud between Science and Religion. Galileo (1564-1642), father of modern physics, astronomy, cosmology, mathematics and philosophy, was put on trial by the Catholic Church and convicted. This has never been forgiven.

We spend billions of dollars listening 24/7 for repeating radio waves, sending rovers to drill rocks on Mars, search the nearby stars for signs of “Earth-like” planets, and so on just to have at least some evidence that life has evolved on some other planet in the galaxy or moon in our solar system. It’s such an important endeavor that finding an alien and a UFO from space would delight scientists. If only. Unfortunately, we don’t even have a fossil of a microbe from space. No evidence at all.

We have no proof life exists anywhere in the universe other than Earth. Given a planet with the right conditions, life can spring from matter and eventually evolve into something greater. No God required. It’s the wet dream of science, but still an unproven theory.

Second, people taking life for granted here on Earth and destroying it because – even in our schools – children are being brainwashed to believe the Earth was created 4,000 years ago and not 4.5 billion years ago, and that God created life on Earth and all life and things on Earth are meant for the descendants of Adam and Eve to rule over and enjoy. That mentality drives people not to care about what we do to Earth.

How long would it take to travel to the nearest star?

Spock and Kirk

First officer Spock (left) and Captain Kirk on the Starship Enterprise don’t float inside because of “artificial gravity.”

Proxima Centauri, is our nearest star, about 4 light years away.

A light year is the distance light travels in one year, or 9,460,730,472,581 kilometers. That’s 9.46 trillion kilometers, or about 5.88 trillion miles.

The fastest space ship we ever built was the Juno spacecraft, which in 2016 broke all speed records in space with a gravity assisted acceleration up to 164,700 mph.

The problem with going much faster than that is General Relativity and propulsion. Even with all the fuel in the solar system, it would still take an infinite amount of fuel to approach the speed of light. There’s no warp speed or aliens that have somehow “broken” the laws of physics. You can’t approach the speed of light.

If, however, you could go, say 40 times faster than Juno (there’s no existing technology that would come anywhere near this speed), you’d be going about 6.58 million miles an hour. That’s a hypothetical but impossible speed by either humans or space faring aliens, but none the less, for the sake of argument, let’s say you could go that fast.

Light travels at 670,616,629 miles per hour (as a layman and lazy American I think in miles more easily). So your space craft is amazingly, impossibly, traveling slightly less than 1% the speed of light. We’ll round it up for arguments sake. You’re going now 6.7 million miles an hour. Don’t crash into an asteroid at that speed!

How long would it take to make the trip to Proxima Centauri 4 light years away? Well, if you were going 1% the speed of light (6.7 million miles an hour) it would take you 400 years to reach the nearest star.

Unfortunately, you can’t just get up and go 6.7 million miles an hour. You’ve got to build up speed, which conceivably would take years burning some kind of fuel source that would weigh as much as the Moon because you’d need so much of it (which would slow your acceleration). The problem is the faster and longer you want to burn fuel, the more fuel you need, which increases your weight and decreases your acceleration. Remember, also, as you approach any percentage of the speed of light at all, the amount of fuel required to accelerate your spacecraft any faster begins to increase exponentially because of the law of General Relativity.

At the other end of the trip you’d need the same time and fuel to slow down so you don’t overshoot your target.

People have thought about using light propulsion. From somewhere in Earth orbit, shooting a powerful laser at a reflector at the back of the outgoing spaceship. It would be slow, but eventually it would increase in speed. They’d still need fuel at the other end to slow down.

It’s difficult to know how to figure in that acceleration and deceleration process, so I usually, for the sake of argument, just double the time, which probably isn’t far off.

That would mean it would take you about 880 years to start out, accelerate to 6.8 million miles per hour, and then slow down at the other end. That’s how long it would take to reach our nearest star.

As far as we know, there’s not even any interesting planets over there. If you want to go somewhere more interesting you’d probably have to go farther out in a different direction to the Trappist-1 system, which is 40 light years away.

That would only take you 8,000 years each way. We’re talking eight thousand years. You’d need a generational spacecraft, where hundreds of people lived and died for thousands of years before they reach where they’re going. Would these descendants of the original pioneers have any idea what to do when they got there? Would they resent being in space because their ancestors decided they should be? Would the spacecraft hold up and not fall apart after 8,000 years of usage? How would they have enough food and water?

Depressingly, these are only the closest stars, right around our neighborhood. There are many more stars in our local group, and billions more in the galaxy, and millions of galaxies.

All we can do is watch them, study them, wonder about them and so on. We will, however, never be able to visit them, and those aliens out there unable to visit us.

Meet Bennu, the small asteroid that could kill you.

In 2035, to be precise. It’s a Thursday. It looks something like this and is about the size of the Empire State Building.

If it does hit us it’s going to destroy a lot of things on the planet, but not kill us completely. It’s not an extinction event, just a big bad event.

Bennu has only a 1 in 2,700 chance of actually hitting Earth. It’s too early to say of those odds might change. We have near misses of asteroids all the time.

If it does wind up heading straight for us, we’ll know in advance and then NASA wants us to think that Bruce Willis will go up there and shoot it down.