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Why this year’s total eclipse is a bright opportunity for science

August 16, 2017 at 6:15 PM EDT
A dazzling spectacle will grace the United States from coast to coast on Monday, when the moon passes between the sun and earth, climaxing with momentary darkness. Science correspondent Miles O’Brien joins Hari Sreenivasan to discuss the science and what to expect as millions plan to witness a out-of-this-world eclipse.
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HARI SREENIVASAN: In our Leading Edge segment tonight: the eclipse.

Monday, the United States will experience the first coast-to-coast solar eclipse in nearly a century. This dazzling spectacle happens when the moon passes between the sun and the Earth, blocking out the sun and plunging the Earth into momentary darkness.

For more about what to expect and how to view this rare event, I’m joined by science correspondent Miles O’Brien.

Miles, I tried to do it justice.

Explain what is happening.

MILES O’BRIEN: Well, Hari, the place to be is a swathe from Salem, Oregon, to Charleston, South Carolina. That is a big, long path across the United States where you will see a total eclipse.

The moon will pass in front of the sun. And here’s one of the great coincidences of nature. The moon is 400 times smaller than the sun, but the sun is 400 times farther away. And so, the optical illusion is that they are the same size, the moon passes in front, it completely covers the sun’s disk, allowing people to experience an amazing, beautiful thing.

And it does give scientists an opportunity to study the sun’s corona.

HARI SREENIVASAN: This happens. It just doesn’t happen this often over the United States.

MILES O’BRIEN: It happens about every 18 months.

But, remember, the planet is about 70 percent water. And then there’s a couple of other factors that are involved here. The moon’s orbit is tilted about five degrees, and so to have it line up just perfectly doesn’t happen every time.

In addition to that, the moon’s orbit is elliptical, so sometimes it’s a little bit farther away, and you get what’s called an annular eclipse, meaning you still see a ring of fire around the sun.

HARI SREENIVASAN: All right, you’re going to be where? And I’m imagining all the places along this line are preparing for people like you who are going there.

MILES O’BRIEN: Yes. Eclipse excitement is running high all across the nation.

There are people that are — well, put it this way. Airbnb owners are doing very well right now. I’m going to be in Irwin, Idaho, which is right underneath the path of totality. It’s likely to be a nice, clear day this time of year. That’s another factor. It’s at a nice high altitude, which helps.

And I’m going to be doing a Facebook livestream for “NOVA” and the “NewsHour.” We will hope you will join us during that. And we’re going to be watching with great care, which is an important point, of course.

HARI SREENIVASAN: Yes, let’s — OK. So, you have your place picked out.

How do you see this safely?

MILES O’BRIEN: OK.

So, let’s just say this as many times as you can. Kids, do not look at the sun directly. Except for that two minutes or so when it’s in totality, as they call it, it is very dangerous.

What happens is, when we look up at the sun right now on a normal day, it’s our reaction to turn away. It’s too bright. The sun is still very bright even when it’s covered in great portion by the moon. And so that natural reaction goes away, and so you can hurt yourself.

So, here’s what you need to do. Get some of these glasses, which are kind of Mylar, very dark. Make sure they have an ISO certification on them indicating they are the right darkness. There are some counterfeit glasses out there. Amazon sold some of them.

They’re taking — they are going to give you your money back, but please, please, please make sure you didn’t get a counterfeit pair of glasses that was a particularly malicious thing for somebody to have done.

The backup plan, if you can’t get the glasses — and you go to libraries — planetariums might have the glasses, viewing parties.

HARI SREENIVASAN: Yes.

MILES O’BRIEN: Number 14 welder’s glass is a good thing.

Or you can make a pinhole camera, as I did back in the ’70s.

(LAUGHTER)

HARI SREENIVASAN: OK. You mentioned that scientists are going to be studying this. What do they need to figure out?

MILES O’BRIEN: Well, the corona of the sun is of great scientists interest to anybody.

For some reason, the corona is actually hot than the center of the sun itself. And no one really knows why that is the case. Above and beyond the scientific pursuit on that front, coronal mass ejections, the corona itself, can be very dangerous to our planet and have in the past caused problems for a communication satellite and the power grid.

So, the more we understand how it operates, the more we can predict these kinds of things and shield the sensitive aspects of our society that might be affected by it.

HARI SREENIVASAN: So, are scientists going to be studying this from the ground? Are they going to fly along with it?

MILES O’BRIEN: They actually — NASA is going to loft two former Cold War bombers that are rigged up as observatories.

They will fly along the path of the eclipse. They’re going to be going about 700 miles an hour. The eclipse moves at about 1,500 miles an hour. So they can’t keep up, but with two of them operating in tandem, NASA figures they will get about seven minutes of totality, which, for us in Idaho, we’re only getting about 2.5 minutes.

So, in theory, they are going to get a lot more data.

HARI SREENIVASAN: Even if we’re not in path, in this perfect path, what are we likely to see?

MILES O’BRIEN: Well, a good chunk of the U.S., most of the U.S. — you will be in New York City, for example.

You are going to get 70-plus percent coverage of the sun. That in and of itself, is a very striking thing and worth taking a look at it. If the weather supports it, by all means, with the safety measures taken, go out and take a look. So, if you don’t want to spend the money on the $2,000-per-night Airbnb, if you can’t just get to the path of totality, which goes from Oregon to South Carolina, by all means, take time, middle of the day Monday, to take a look. Make sure you do it safely.

HARI SREENIVASAN: Or, if you’re not in any of those places, you can certainly follow along live on Facebook on the NewsHour page, on the “NOVA,” page.

And you’re going to be doing a special about this as well?

MILES O’BRIEN: Well, yes.

And, as a matter of fact, we will be doing the streaming during the day, and then “NOVA,” on the night of, that evening, will have a show that will air, “Eclipse Over America.”

And so we invite all our PBS viewers to watch that as well.

HARI SREENIVASAN: All right, Miles O’Brien, thanks so much.

MILES O’BRIEN: You’re welcome.

HARI SREENIVASAN: And a news update before we go.

In Venezuela, at least 36 people are dead after security forces raided a prison in the country’s south. Officials say it came after fighting erupted between inmates and prison staff. It’s still unclear if the bloodshed is tied to months of political unrest in the country.

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