Category: The Universe

Is outer space empty? How is that even possible?

By Wayne Boyd

Air pressure works like water pressure. The deeper you go in water, the more the pressure because of the weight of the water above. Similarly, the lower you go in the atmosphere the more the pressure. At sea level, air pressure is normally about 14.7 pounds per square inch. This can be measured with an altimeter, which is used on aircraft.

Mount Everest is so high that climbers usually need to carry oxygen to go the summit. Commercial airlines go even higher.

When you get about 62 miles up (100 km) you’re at air pressure that is basically zero and you are above most of the atmosphere altogether.

The International Space Station orbits around 250 miles up, but there is still some, very thin atmosphere up there that eventually slows down the ISS, requiring it to be boosted once in awhile.

Eventually you come to deep space, and there are some molecules floating around out there, just not very many. So space isn’t completely empty, just mostly empty. Sometimes there are molecular clouds in space in regions where stars are forming, and the molecules floating around are a little denser.

If you went outside on a spacewalk on your way to Mars, took an empty bottle with you and opened it and then sealed it, once inside the spaceship you’d find your bottle had nothing but a vacuum in it. The free floating molecules out there are so sparse you’d not find any inside your little bottle.

What might happen if other beings outside our solar system finds Voyager 1 and Voyager 2 with the media inside them, named The Golden Record?

By Wayne Boyd

The human race will be much changed. The reason the golden record was included on the Voyager spacecrafts was twofold. The main reason was a mechanism to inspire public interest (and therefore funding) for the project, which was to explore the outer planets in our solar system and interstellar space. The other reason was that Voyager I was going to pass within 1.6 light years of the star called Gliese 445 in about 40,000 years. In case any intelligent space traveling beings over there might notice Voyager I drift by their star 1.6 light years away, they might go out, retrieve it, and discover the Golden Record.

To compare that to us, if an alien spacecraft the size of Voyager I passed by within 1.6 years of our own sun we would not be able to detect it. It’s too small, and out many times farther than the Voyagers are now from Earth. It would be many times outside the solar system entirely.

Gliese 445

Now, let’s assume that 40,000 years from now Voyager I is drifting by within 1.6 light years of Gliese 445 which is 17.1 light years away from us and alien astronomers on a planet over there did somehow notice it. Let’s say their alien scientists then launched a probe to investigate and find the Golden Record. What would happen? That’s the essence of your question, right? Well, let’s look at it.

To send a probe from an alien world to Voyager I as it passes by the star Gliese 445 their probe would have to travel 1.6 light years, which would take thousands of years. But once reaching Voyager I, the probe could communicate back to their alien world in only 1.6 years, with a 3.2 year return signal. So let’s say they did it.

The Golden Record is designed to indicate to an advanced alien civilization that other intelligent beings are “out there.” This would be extremely exciting for them to realize someone else (Earth) is out there. They might try to send a radio signal in our direction to let us know the message was received. The message would take 17.1 years to reach Earth, so basically, 45,000 years from now the message from the aliens might reach Earth, but would anyone still be around to listen? My estimate of time is the 40,000 years for Voyager I to reach that far, another 4,000 years or so for their space probe to reach Voyager, and a few years communicating with the probe to figure out what it found. Nothing here is true math. It’s just very round, hypothetical numbers.

Once the aliens realized there was another planet with intelligent beings on it, they might try to communicate with us even though we are more than 17 light years from them.

So a form of communication could eventually be established. Considering the speed of light with a return message taking 34 or 35 years (the time in light years and back) it would be a slow, gradual communication. Interstellar travel between the two civilizations would not be feasible, however. It would take the spacecraft about the same time as it took Voyager, or maybe they could half the time with some kind of alien propulsion system. UFO conspiracies aside, travel over those distances isn’t realistic.

The best could be communication.

Then again, the human race will probably be much changed 45,000 years from now and who knows if anyone will be listening by then, or conversely, if there is an alien civilization orbiting on a planet around Gliese 445 now, will they still be around by the time Voyager I reaches there?

Some people on Earth would not believe it or even care. Scientists, if there are any scientists left 45,000 years from now would be excited. I’d imagine it would be about the same for the aliens, but who knows what kind of organization they might have over there.

Basically, it would be largely ignored by the public.

What do the people of the world want aliens to know?

By Wayne Boyd

Actually, this is an interesting question and I think I can provide an interesting answer.

To know what the people of the world want aliens to know about us, look no further than the Voyager spacecrafts. When we launched them in 1977 they were on a mission to explore the planets in our solar system, but afterward it was known they would be flung out of our solar system to drift in interstellar space for tens of thousands of years, and interstellar space is where they are both now.

So physicist Carl Sagan had an idea to place a golden record on each spacecraft with a message from Earth to any aliens who might come across them in the eons to come. According to Wikipedia, “The records contain sounds and images selected to portray the diversity of life and culture on Earth, and are intended for any intelligent extraterrestrial life form who may find them. The records are a sort of time capsule.”

So what’s exactly on this record, and what did mankind in 1977 want future aliens in space to know about us? The contents of the record were decided by a committee from Cornell University and headed by Carl Sagan. It took more than a year to decide on the contents, and contains 115 images of Earth and natural sounds of the planet like wind, surf, thunder and whales.

There’s images of DNA and music by Mozart and Beethoven and a whole bunch of other stuff to indicate we are an intellectually and culturally developed civilization of beings.

Do you believe in aliens? Do you think that we can ever get in contact with them?

Yes, I believe in space aliens, and unlike others, no, I don’t believe they are “here” nor do I ever think they will ever be able to come here, nor us go there.

Space is so big, that given we’ve been emitting radio waves for over a hundred years, the radio “sphere” in space coming from us hardly encompasses very many stars at all. We live in a huge galaxy, one of billions of galaxies, and in our little corner of our galaxy our radio waves, traveling at the speed of light, haven’t even reached a significant portion of our own galaxy.

In the image below, you can see just how tiny an area that is, represented by the small blue circle, or dot.

That being the case, unless there are aliens that want to visit us and “hide among us” (for whatever reason), they’d really have to come from somewhere pretty close.

I don’t see it.

Regarding “UFOs,” aka unidentified objects in the sky, there are many natural phenomena that we don’t yet understand, but to take it there is something we have yet to identify and then extrapolate that it is some kind of alien spacecraft visiting across thousands of light years just to come here, is more than a stretch. It’s not science.

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.

How far and how big are the stars from the Earth?

We are in a galaxy with a lot of stars. It is estimated to contain 100–400 billion stars, The nearest galaxy to ours is Andromeda, but the stars within our galaxy, the Milky Way, are from about 4 light years away to about 100,000 light years away. We can see the Milky Way with the naked eye, and it looks, to the naked eye, like a light smear of milk across the night sky. You can’t see the individual stars that are far away, even within our own galaxy. In the Milky Way galaxy there are, as I said, many stars, but in our night sky we can only see about 9,096 individual stars.

Time Portal

Even as Gene stood with his back toward the chalkboard, sweat beading on his forehead, the blue disc hovered silently if not defiantly.

It was baffling. Nothing was reappearing on the other side.

Where did everything go? They’d tossed in a pencil, alarm clock (with the alarm sounding), a handball, a basketball… All had vanished.

The calculations seemed simple enough. A 60-second time portal. Things were disappearing when you threw them in but weren’t emerging from the other side a minute later as they should. Calculations were recalculated and double checked. Everything was as it should be. What was happening here?

So now Gene rested his hand on a powerful transmitter sitting on a cart with wheels. He planned to push the cart through the portal and have them search for the signal that emitted from it 60 seconds in the future.

So the cart was wheeled forward and pushed into the portal where upon it abruptly vanished from sight.

The technicians placed on their headsets and adjusted the dials on their radios while a 60-second timer was initiated. Find the signal 60 seconds from now and they would know where things were going and why things weren’t reappearing on the other side.

What they discovered was truly astonishing, but in retrospect completely logical.

Yes, the signal was detected. Very faint and very distant but completely detectable. So where did the transmitter go?

The transmitter was in space, apparently orbiting the sun, thousands of miles away from Earth.

In the sixty seconds that the transmitter traveled into the future, Earth itself had moved away by thousands of miles.

At the equator, the rotation of Earth is about 1,037 mph (1,670 km/h), or over 17 miles a minute. Meanwhile, Earth has an orbital speed around the sun of about 67,000 mph (107,000 km/h), or about 1,100 miles per minute. The sun and the solar system orbit the center of the Milky Way Galaxy at approximately 448,000 mph (720,000 km/h) or 7,466 miles per minute.

So when the transmitter was pushed into the time portal and jumped 60 seconds into the future, the Earth spun around it’s axis 17 miles at the equator, 1,100 miles around the sun and 7,466 miles around the galactic center. Simply put, the transmitter came out sixty seconds later exactly where it went in, but Earth itself was no longer in that location.

Therefore the pencil, the ringing alarm clock, the handball, basketball and the transmitter all emerged into space, orbiting the sun over 8,000 miles behind Earth’s orbit.

It turns out the time portal was the easiest and most efficient way to send things into space.

You can see it too: a star is changing

A week or so ago I was getting out of the car parked on the curb outside my house and looked up. I had heard about Betelgeuse, one of the stars in the Orion constellation. Lately it was growing dimmer. I wanted to see if I could notice it and sure enough I could. With the naked eye.

You can too because this is one of the more noticeable stars in the sky.

Most people that look up at the sky at night in the northern hemisphere are familiar with Orion’s belt, three stars in a closely near straight line. Above that line there are two stars and below that line there are two stars. The star in the upper left is Betelgeuse, and it’s different than it was even a few months ago.

Betelgeuse is a very big star many many times larger than our own sun. It is expected that this star will explode one day and although it’s unlikely to do it within our lifetime, this dimming of the star and it’s exceptionally orange color visible with a naked eye it does indicate that Betelgeuse could be near to going supernova.

So now you know how to find it, go out and look at it the next time it gets dark around your house and the sky is clear.

Scientists say we can never reach exoplanets, but is it possible to send probes to nearby stars?

Is it possible to send probes to nearby stars?

Yes, and no. We can send probes out of our solar system as we did with Voyager I and II, and theoretically we can direct future probes toward specific exoplanets, but alas.

The distances are so great, even for the nearest exoplanets, that we will all be long dead before they ever reach there.

How’s that I say? I mean, Proxima Centauri is only 4.2 light years away! That’s very close astronomically speaking, isn’t it?

Voyager I is the fastest of the two Voyagers. It travels about 3.6 AU per year, one AU being the distance from Earth to Sun. Proxima Centauri, also known as Alpha Centauri C, is about 268,770 AU. That would take a craft traveling the speed of Voyager I about 74,658 years to reach Proxima Centauri.

So theoretically we could send a probe out there, and when it arrives it could send a signal back to Earth. That signal would take 4.2 years to reach Earth, but would be more than 74 thousand years from now. Who knows if humanity will even still be here by then or if anyone will be listening?

That’s just the nearest exoplanets. Others are much more distant than that.