Mike F.

Could Extraterrestrials Visit Earth?

“We need some idea of their starting point.”

Could intelligent beings from a planet outside our solar system visit Earth in the near future? I’m not asking whether they have visited us or will visit us, but whether they technically could. Could? I technically could do cartwheels across the floor, but I won’t for various reasons (including my age and an aversion to hospital bills). But I’m still able to do so if I wanted to; therefore I could. So, could extraterrestrials visit our planet soon, as in could it technically happen (assuming they exist)?

More specifically, have extraterrestrials had enough time to evolve, acquire intelligence, and develop sufficient space travel technology to make their way here in (approximately) our time? We humans are the only intelligent life we know of, and our planet Earth is the only planet we know to have ever had life on it. So we’re going to use the history of humans and Earth as a yardstick for this question. Admittedly, our current space travel technology seems quite challenged by the scale of the cosmos.

It took 4.6 billion (Earth) years for our Solar System to form and for us humans to make it into space, so we might expect a similarly long time for the extraterrestrials too.[1] That 4.6 billion years includes the entire history of life on Earth so far, including the development of our space technology. In fact the past couple of millennia leading up to our development of space technology is insignificant compared to a billion years and could be ignored anyhow. Even another million years wouldn’t matter much, mathematically. On the bright side, this simplifies our calculations. Naively, we could just look for a planet reasonably like Earth that is orbiting a star at least as old as our sun, that isn’t too far away.

Unfortunately, this also means that Earth may very well be visited for the first time by extraterrestrials after everyone who is currently alive, has died of old age. Or maybe our visitors showed up long enough ago that no one was here to adequately greet them. It certainly would be nice if someone alive today (including me) could meet space aliens visiting Earth, assuming they are friendly. If they aren’t friendly, it’s just as well to leave that problem for a future generation, who has sufficient technology to defend Earth against them. The calculations here won’t be accurate enough to indicate how good our visitor’s timing might be for the current residents of Earth.

Now the question is how long would it take extraterrestrials to actually travel here from their own solar system. There’s the standard distance formula of r*t = d (rate times time equals distance), which can be rearranged as t = d/r to calculate travel time. Starting with r for rate of speed, for simplicity we’ll assume the extraterrestrial spacecraft is as fast as ours. How fast is that? The spacecraft with the fastest reported speed is the Parker Solar Probe, which reached a record speed of 192 km/s on December 24, 2024.[2] Admittedly, the craft used gravity to help achieve that speed, but at least it’s possible. And why not take advantage of gravity to cover a large distance more quickly? So this speed will work for our purposes.

Next is d in the formula, the distance our visitors would have to travel to us. We need some idea of their starting point. Reportedly the closest Earth-like exoplanet (a planet outside our solar system) is Proxima Centauri b, which orbits the closest star, Proxima Centauri.[3] We hear that Alpha Centauri is the closest star system to Earth, and that’s true, but that star system has 3 stars. Proxima Centauri is the closest of those stars, and Proxima Centauri b is a planet orbiting that star. Anyhow, Proxima Centauri b is 4.2 light years away from our solar system. A light year, as you may recall, is the distance that light can travel in one year.

Now we just need to divide the distance by the rate, to determine the travel time. But the distance is in light years, and the rate of speed uses kilometers. It’s fairly easy to find on the web that a light year is roughly 9.46 * 10^12 kilometers (9.46 times ten raised to the twelfth power).[4] Proxima Centauri b (our chosen starting point of our interstellar visitors) is 4.2 light years away, which comes out to 3.97*10^13 kilometers. Dividing that by our spaceship speed of 192 km/s comes out to about 2.1*10^11 seconds. But how many years is that? A year is roughly 3.16*10^7 seconds, so the space craft would take about 6,600 years to make the journey. That is not a short amount of time for our visitors (or us) to travel.

Back to the question of whether having visitors is technically possible at all, we again see that what’s really significant is the age of the star and planet they come from. Is the star even old enough to have evolved life like Earth has? The age of the host star Proxima Centauri is estimated at 4.85*10^9 (4.85 billion years), which is slightly older than our sun. The age of the planet Proxima Centauri b is unknown, so we don’t know whether there has been enough time for life to develop, acquire intelligence, develop space flight, and find it’s way to us. We don’t even know if the planet supports life, though it’s believed to be the right distance from its star to have liquid water, if there is any.

Looking at a good alternative just in case, there’s TRAPPIST-1e, which is 40.7 light years away.[5] That comes out to 3.85*10^14 kilometers. Dividing that by our spaceship speed of 192 km/s comes out to about 2.01*10^12 seconds. That in turn is equivalent to about 63,300 years. That’s roughly 10 times longer than the other, which was long to begin with. But what about the age? TRAPPIST-1e orbits TRAPPIST-1, a star that is estimated to be 7.6 billion years old, which is older than our sun, which is only 4.6 billion years old. That gives our hypothetical extraterrestrial visitors an extra 3 billion years to evolve, develop adequate technology, and come visit us. Again there’s the question of whether life could start and survive there, but that question will exist until we actually find extraterrestrial life.

How long of a trip is too long? Maybe whatever makes a difference compared to 4.6 billion years, arbitrarily because it would affect our calculations. So maybe 100 million years might be too long for a trip. That means we could expect visitors from 1000 times as far away. It turns out, the center of our Milky Way galaxy is about 27,000 light years from us, which is less then a thousand times as far as TRAPPIST-1e.[6] That alone indicates there probably has been enough time for us to have extraterrestrial visitors, even if their space technology is as slow as ours currently is. But our galaxy seems to be over 12-13 billion years old, which seems to give them even more time to come knocking on our proverbial door. Of course, our solar system has only been around for 4.6 billion years. Still, there are probably plenty of stars that are roughly our sun’s age, that could have planets with life that could visit us.

So, yes, extraterrestrial visitors are possible, when looking at the aspect of time alone. The theoretical possibility is exciting, inspiring, scary, and humbling, all at the same time. Why would they even visit us though? The center of the galaxy is said to have a very massive black hole, which is an object so dense, that even light can’t escape it, due to gravity. I would guess that it didn’t start out that big, meaning that matter around it could eventually fall into it. Being literally crushed by strong gravity could very well motivate extraterrestrial life to find us, very far from the galactic center. Radiation given off by matter that is being pulled in, could also offer motivation. So we very well be getting some extraterrestrial company some day, after all.

References

[1] https://en.wikipedia.org/wiki/Sun

[2] https://www.guinnessworldrecords.com/world-records/66135-fastest-spacecraft-speed

[3] https://en.wikipedia.org/wiki/Proxima_Centauri_b

[4] https://earthsky.org/astronomy-essentials/how-far-is-a-light-year/

[5] https://en.wikipedia.org/wiki/TRAPPIST-1e

[6] https://en.wikipedia.org/wiki/Milky_Way

Hello, World

“…hundreds of millions of years.”

In software development, it’s something of a tradition to write a “hello, world” program when learning a new programming language.[1] It’s often just a simple program that prints the words “Hello, world” on the computer screen, to prove it can be done. Getting this proof of concept to run, can tell us multiple things: the programming environment is set up correctly, the program source code is correct, and the steps to run the program from the source code are effective. It can also be a confidence builder as well as fun. But the general concept of it is far more than any of that.

A Quick Look at Unlucky 13

“Maybe it’s nothing so deep or analytical.”

With Friday the 13th coming up, it’s hard not to wonder about the number 13. Is that number really a source of bad luck, or is that just in the imagination? Various reasons have been given for 13’s reputation, some of which are related to Christianity and the Christian Bible[1]. Also there are various discussions of “perfect” 12 being more common, like for the number of months. But the calendar is more of a long-term thing. I’m looking for a more practical everyday reason.

Unreal

“…even when there was nothing but air in between.”

How real is our everyday life? Most people probably have some experience with artificial colors or flavors in food or maybe even hair coloring or colored contact lenses. There are also reports of fake news that didn’t happen and so-called “deep fake” images that look like actual – but nonexistent – photos. Recent advances in generative AI tend to accelerate such fake media trends. But living with what is not real is nothing new.

Stop Refactoring Your Code

“…also write dumb code.”

If you know much about software development, then you probably have some idea what refactoring is. It was made more popular some years ago by Martin Fowler’s book Refactoring, which defines the term as “improving the design of existing code.”[1] The code referred to, is of course software source code, the specialized text used to tell a computer how to perform some task. It’s generally accepted that refactoring is a good practice for fixing unruly code, as the schedule allows. Then why does my title for this blog entry tell you to stop refactoring your code? There’s more here than meets the eye.

Natural Processes and Life

“But the sacrifices?”

The recent full moon may or may not have turned someone into a werewolf, but it did remind me that the moon can influence the behavior of animals, just like the sun can. Both are part of the daily cycle of day and night as well as the rising and falling tides. There are many cyclic processes in nature, interacting with each other. Many are such a part of our lives, that they have been given names as if they were people. For example, Jack Frost has recently visited my neighborhood. Treating complex natural phenomena as intelligent beings could just be poetic license, but maybe the basic idea is not so far-fetched. Could “nonliving” natural processes have intelligence or even be a form of life?

Witches’ Brew

“But what if there’s more to it than that?”

Like other aspects of culture, witches have stereotypes that are fueled by tradition, fiction, and modern media. A well-known aspect of witch stereotypes is the brewing of potions or witches’ brew, often in a large black cauldron. The purpose of a potion could be to cure illness, obtain immortality, or try to “induce love”, according to Wikipedia.[1] Other historic purposes for witch’s brew can be found on the web as well. The ideas for tradition and fiction are often based on truth. In fact, the mixing of natural ingredients in potions eventually helped bring about modern medicine. Could there be any truth to other supposed uses of witches’ potions, beyond potential use as medicine?

The Top or the Bottom

“We may still need something closer to our scale…”

We humans like to think of ourselves as the dominant lifeform of Earth, having the power to help or hurt any and all life on the planet. Mainstream science depicts us as naturally intelligent beings using technology to help us do things, harnessing nature as we see fit. Do we have it backwards? Is nature harnessing us? What if we are the technology?

COBOL’s Innovative English Mimicry

“In my opinion, it excels at that, even better than modern programming languages.”

Years ago, I took a college course on the COBOL programming language while studying computer science.[1] The version of COBOL being taught in the course was from the 1960s or 1970s. Having already learned some Pascal and FORTRAN, I was disappointed with what COBOL apparently lacked. While COBOL had what might best be referred to as “subroutines,” the subroutines in our programs did not have have parameters, return values, or even local variables. Yes, all data was global, a situation that has been blamed for at least a few problems in faulty software. I don’t recall whether such features were absent from the version of COBOL we used, or if they simply did not fit into the scope of that one-semester course. Regardless, even that old version of COBOL had a quality I found very impressive then, and even more so now.

The Universe Doesn’t Care What We Think

“Reality is simply not that convenient.”

Some (most?) people may not care what I think, and that’s fine. But I think the physical universe doesn’t care what any of us thinks. In attempting to explain the universe or the part we experience, just about any theory we throw at it, has limitations that make the theory inaccurate under certain conditions. The experimental results and theories from physics can be different enough from our everyday experience, to make it seem presumptuous to expect the universe to behave the way we normally perceive it or to understand why it does what it does. Relativity and quantum physics come to mind.