Name: 最初の恒星間訪問者が来たばかりなのに...変な感じだ。 (We just had our first interstellar visitor...and it's weird.)
Uploaded: 2021-01-14T10:32:38.000Z
Duration: 10 min 18 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

A little over a year ago, we observed the first ever object that wasn't from here.

過去完了形

Ah, hunk of something that had traveled from another star system may be thrown out as the system formed may be flung out much later.

But now we know officially, while we cannot visit other star systems, pieces of them can visit us.

Let's start with what we know on objects came into our solar system going around 25 kilometers per second, which is pretty fast.

So we'd look at it one day and it would be 10 times brighter than on another day.

A huge surprise, which is where we got the cigar hypothesis.

So when it was like, this had reflected more light than when it was like this tumbling end over end changing and brightness.

There are no objects in our solar system shaped like this.

Movie has a length to with ratio of 10 to 1.

There are barely any objects in our solar system with a ratio of 5 to 1.

How would an object like this form, we don't know.

Probably something very sturdy or else it couldn't maintain this strange shape.

It brushed surprisingly close to Earth right into the habitable zone of ours, son.

And then maybe the weirdest bit of all its velocity changed in ways that could not be explained by gravitation alone.

There are, as far as we can tell, only two ways.

Omura is a comet, and it off gassed 10% of its mass as the sun heated it up.

Instead of being a big rock, it's a 50 meters square of shiny foil, less than a millimetre thick, which fans of space travel and or science fiction will recognize as the description of a solar sail.

See, weirdly enough, photons do not have mass, but they do have moe mentum, and when they hit something, they give it a tiny push.

A big sheet of something very reflective, but very light weight can take advantage of that fact and use it for propulsion, something we humans have actually experimented with.

Obviously, a comet is a much more likely thing.

Toe have floating through interstellar space.

But until we noticed the velocity change, we were pretty sure that Omura wasn't a comet.

For one thing, it was long and skinny, and that is a shape that is very difficult to have occurred naturally at all.

But even more difficult if it's not something that's rigid, and comets generally are fairly loosely held together, balls of ice and dust.

The idea is that would definitely break apart, especially as it approached a gravitational well, like our song.

Now it's certainly possible that the change in brightness isn't caused by its unique shape.

It could be that it's just much darker on one side, then the other, like Saturn's moon.

So maybe we've just learned that it isn't such a weird shape.

Also, we didn't think it was a comic because there was no tail as it off gas that theoretical 10% of its mass.

We probably would have seen some of that mass, but maybe there are comet like things from other solar systems that out gas differently from our comments.

Different compounds different sized dust particles that would make it more difficult for us to detect.

Finally, scientists think the off gassing would have changed the rotation of the object, which it appears to not have now.

Adding to the solar sail hypothesis, the Spitzer space Telescope pointed at the place where oh muumuu awas, and it did not receive any thermal readings back.

No infrared radiation, meaning that it was very dim in the infrared.

So probably it had reflected away most of the heat received from the sun.

It means that the object has an upper limit on how dark it can be.

And that limit is shiny er than either asteroids or comets from our solar system, which, like thank you Spitzer Space Telescope.

This was not what you were designed for, but that is very helpful in weird piece of data.

The telescope that spotted Omura does the Whole Sky Survey and is not designed to catch things like this.

In fact, it didn't spot the object until it was well past its peak brightness.

The fact that the Pan Starrs telescope caught an object like this in the 1st 10 years of operation means, statistically that these events are probably very common.

But according to our computer models of how solar systems form and how much stuff they threw out, it should not be common.

And this discovery, if it's natural and common, means that we were off by like orders of magnitude.

And it's actually wonderful news that it did occur, because if it means it's more likely, then we will have more chances to study objects like this in the future because we definitely do not understand what this thing, what's, I don't know.

Maybe there's a natural way for a solar sail like object to form in the galaxy.

In general, jumping from this is confusing and weird, and I don't understand it, too.

It's aliens has tended to be a bad way to answer questions in the past.

On As Carl Sagan said, extraordinary claims require extraordinary evidence which we as oh muumuu a speeds off away from us, do not have and will never have now, of course, arguing against the extraterrestrials created a light sail hypothesis are two main things.

One Why would it be tumbling end over end.

If you wanted to create a space probe to study a planet, you probably want to keep everything relatively stable so that you could point stuff at the planet to study too.

25 kilometers per second is very fast to us, but very slow in terms of interstellar travel.

It would take about 12,000 years if you were going straight at Alfa Centauri to get there from here at that speed, this leads to alternate hypotheses like, Hey, there are more shipwrecks under the ocean than ships currently floating on the sea.

So maybe this is the piece of something that broke down or ripped apart through age or accident or attack.

It's artificially created, but it's 100% dead just floating through space.

Because if we're going to start hypothesizing, we might as well start hypothesizing about inter stubborn for ah, unless this is an extremely uncommon occurrence, debris from an event like that would have to be way too common.

If there was that much detritus floating around in the galaxy theory, I haven't heard from anyone except my own brain is that maybe this thing is tumbling end over end and not going very fast because whoever sent it wanted us to see if maybe they thought if there was some group of intelligence is significantly advanced, they could chase such an object down.

Maybe it's nothing more than an interstellar greeting card blinking off into the distance, unreserved this time, at least I shouldn't have said that.

That was pure conjecture, and I probably shouldn't even be making this video at all.

As a person who hosts a science show, has a master's degree and looks like this, I am credible, and I want to hold on to that credibility and also use it wisely.

Observing an interstellar object on its own is huge news.

It means that these objects arm or common and more weird than we thought.

But the story that would truly captivate all humanity is if we found out for sure that this thing came from somewhere else, someone else.

Our minds should not have an effect on how scientists consider that hypothesis, but it does have an effect on how it is perceived by us.

It hasn't effect on how we're gonna write that headline.

Make that video and whether we're gonna click that link as a science communicator.

I'm aware that people are going to see the sentence.

This is probably not a spaceship and Seymour of the probably part of the sentence, then the is not part.

So I'm aware that bringing up the possibility that there is explanatory power behind the hypothesis that oh muumuu was constructed by an intelligence outside of our solar system is going to inevitably lead people to looking much more at that part of the story than the parts where there might also be lots of other explanations.

This is, for example, true of me because I wanted to be a spaceship.

I wanna have an event like that where we all remember where we were when we heard the news.

Just the big news is ultimately, I know that I'm not gonna be ableto trust myself with this one.

You know, I'm trying to get more things that way, knowing that there are certain things that can't really trust myself with because I want things to be a certain way, and it's especially easy to see in this case where the event was ephemeral.

The data has been collected and analyzed, and now all that we have left to do is speculate.

Right now, we have only one telescope that could have spotted Omura.

Another is going online in just a few years, and it will be orders of magnitude Better.

If when we get that telescope online we see objects like this floating through the solar system all the time.

We may be able to determine that they are a new class of object, understand them, study them, even visit them.