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.

If I went into space with an open bottle and then sealed it, what would be inside the bottle?

by Wayne Boyd

A lot of space.

In theory, space is nothing, so the bottle will have a vacuum – an empty bottle. In reality, space is not empty, just mostly empty, so the bottle might have a molecule or two, but most likely it will have nothing.

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.

Do you know if NASA has evidence of alien life?

Yes, I do know the answer to this. It’s no, NASA has no evidence of alien life to date. We only have theories and speculation, but without evidence there is no proof of alien life anywhere else in the universe other than good ol’ Earth.

That being said, most scientist believe life probably exists elsewhere in the universe, but until we actually find even a fossil of a microbe of alien life, there’s no evidence to date.

If you were on the ISS, would the view of the stars be completely clear with the lack of atmospheric distortion and light pollution? If so why aren’t there more pictures of it from their pov?

You don’t understand cameras, do you? Well, a quick lesson then. In cameras (other than cell phone cameras), there’s a thing called aperture. When there’s a bright light the aperture has to be small, to let less light in, so you can photograph something like the Earth. This avoids overexposure of the bright objects in your photo. In space, this blacks out the stars.

However, if like the Hubble Telescope, you just look away from Earth at the stars, you see a whole lot more of them than we can see here on Earth.

Here’s a photo taken of the Hubble Telescope from the point of view of the Space Shuttle Discovery. Notice, because the Earth is so bright, we don’t see any stars.

The Hubble Space Telescope (HST) floats gracefully above the blue Earth after release from Discovery’s robot arm after a successful servicing mission.

On the other hand, since the Hubble Telescope points away from the bright light source coming from Earth, we can capture images like these.

If we discovered an alien civilization 50,000 light years away, what do you think our top 3 priorities as a species should be?

If we discovered an alien civilization 50,000 light years away, we’d be looking at that civilization 50,000 years in the past, since that’s how long it took light and radio waves from there to reach us. They might not even be there by now. Will we still be here 50,000 years from now?

Also, it would create conspiracy theories. There would be those who say it was a hoax because it challenges the very idea that God created life on Earth alone. Discovering even a fossil of a microbe from another planet would be an enormous find for science in the age-old battle between science and religion.

It would revolutionize science, but from the average Joe on the street, it would mean nothing at all.

And that’s sad, but true.

So we would remain, as a species, not united as we are not united at present, and therefore we would remain without the ability, as a species, to come up with three top priorities. But if the scientists of the world came up with three priorities they might not be much different than they are now:

  • Save the planet
  • Find our origins
  • Feed our people

If just .001% of 10 billion Earth-like planets orbiting sun-like stars in the Milky Way have harbored advanced, intelligent life, shouldn’t we have seen some kind of evidence of their past existence, since this would equal 100,000 civilizations?

Great question! Complicated answer. Let’s start by looking Earthward at ourselves, then we’ll compare that looking spaceward toward the stars.

As you know, homosapiens are the advanced, intelligent life form on Earth which is now technologically advanced and space faring.

Now by some estimates, humans have been on this planet only for the last 200,000 years, or one fifth of one million years. There are a thousand million years in a billion years, and the Earth is about 4.54 billion years old. So, humans have been on Earth for only a tiny fraction of Earth’s existence. Here’s a graphic to illustrate that point and more to follow below.

This image illustrates what it would look like on a 24 hour clock comparing the age of Earth to the presence of humans. In fact, life itself has existed on Earth for less of half the lifespan of the planet, what to speak of humans.

So you can see, even though we have a planet in the goldilocks orbital region around our sun, someone looking at Earth many light years away would not see humans even though humans are here, because the light or radio waves haven’t reached them. They would assume this a dead planet. Humans have existed on this planet, in terms of a 24 hour clock, 1 minute and 17 seconds. In terms of exploring space, for less than 1 second.

You see, just because humans have been on Earth about 200,000 years doesn’t mean humans have been emitting radio waves and exploring space for all that time. In fact, we only began exploring space 60 years ago and emitting radio waves for a couple of hundred years. In the history of Earth, we have explored space (in terms of a 24 hour clock) for only a flash of a portion of a second.

That’s us. Now let’s look at the stars.

Let’s say there are 100,000 planets with advanced life like humans on them right now.

However, since the galaxy is 200,000 light years across, someone on a planet on the other side of the galaxy from us would not be visible to us. We’d see that as a planet with no human-like people because it would take light and radio waves 200,000 years to reach us. Now take into consideration that of the 100,000 planets with human-like people on them (as you suggest in your question), it took us 200,000 years to get to the point of emitting radio waves and exploring space. Hence, we’re looking for a very narrow window in a planet’s lifespan that intelligent life might be detected. Not only a tiny fraction of the planet’s existence has it had intelligent life, but only a tiny fraction of the time the intelligent life existed there were they able to emit radio waves and explore space, even if all conditions were favorable for that planet to eventually develop intelligent life.

Furthermore, the sky is very big. Looking for exoplanets, we have explored less than 3% of the total sky so far.

Put all of that together and the chance we would have detected other intelligent life is almost nil to date, even though it might still be out there somewhere. The guy below might be the exception.