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JUDY WOODRUFF: There are moments when the power of nature and the elements and the
destruction they can cause simply capture everyone’s attention and make you wonder about your place in the universe.
This week, the lava flow on Hawaii’s Big Island that’s forced people to abandon homes and a sunspot the size
of planet Jupiter are providing such a moment.
Hari Sreenivasan has a look at the scientific phenomena behind all this.
HARI SREENIVASAN: The National Guard itself began trying to help Hawaiians today. The lava that began
flowing this summer from the volcano on Mount Kilauea is endangering a small community of about 950 residents.
It may be moving slowly, at speeds of just five to 10 miles an hour, but there’s been no way to stop it. And now
it’s started to burn homeowners’ property there.
At the same time, a whole different set of fiery images from space may also be in your daily news feed. It’s the
largest sunspot in more than two decades. Federal officials have warned frequently about the possibility that solar flares
could potentially disrupt navigation systems and radio frequencies.
Science correspondent Miles O’Brien is with us again tonight.
So, Miles, let’s start with this planet first.
When we think of lava, we think of huge explosions and volcanoes like Mount Saint Helens or other places, but that’s
not what we’re talking about here.
MILES O’BRIEN: No. No.
With Mount Saint Helens, the more recent volcano eruption in Japan, what we had was called a pyroclastic flow. And that’s
like a — think of it as a steam-heated hurricane. It can travel at — in excess of 100 miles per hour, carry boulders
with it, and can catch people off guard, as we saw most recently in Japan.
This is the other side of the equation for volcanoes, these oozy lava volcanoes that you see in Hawaii which have been
erupting sort of in sort of slow motion. And they move and the fissures crack and lava appears in different places. And
what we’re seeing here now is, of course, as the lava changes its pattern, the patterns of human settlement have changed
There are more people living there. And that’s where the collision is right here.
HARI SREENIVASAN: So, what sort of dangers does this lava pose, in terms of the gases coming off of it,
or the infrastructure that it threatens if it cuts across roads?
MILES O’BRIEN: All kinds of toxic gases associated with volcanoes, sulfur dioxide, many others
which can be hazardous.
One thing about lava, of course, even though this is kind of a slow-motion train wreck, there’s no stopping it.
There’s no putting up a dam to stop lava. This is, after all, the molten core of the earth. It’s hot and there’s
no stopping it.
And so people have got to, unfortunately, respect that, and step away from the lava. You know, we’re talking about
the center of the Ring of Fire here in the Pacific. And, you know, essentially, the Earth sits on 17 giant tectonic plates.
That’s what we’re sitting on right now.
We’re kind of floating on a sea of magma. And wherever there are little cracks in those plates, you get problems.
You either get earthquakes or you get volcanoes. And sometimes it’s that oozy lava that we see in Hawaii.
HARI SREENIVASAN: So, we often have a tendency to think that we can engineer our way around anything.
And speaking of things that we have very little, to no control over, these giant sunspots that we have been seeing, there
are scientific instruments and people that essentially stare at the sun all day long, 24/7.
What is it about what’s been happening over the recent past that have them so concerned?
MILES O’BRIEN: Yes.
Of course, we would advise people not to stare at the sun unless they take precautions, of course. But we’re talking
about a giant sunspot, about equivalent to the 20 Earth diameters, which is hard to even comprehend. Scientists have been
watching is it now for two weeks. It just disappeared. The sun rotates about every 25 days all the way around.
And so, for about two weeks, this giant sunspot is on the backside, if you will. Huge solar flares come off of it. We
haven’t seen the other thing that can occur, which is the so-called coronal mass ejection.
Now, a good analogy for this is, you think of a cannon shot. The flash is the solar flare. The cannonball itself is the
coronal mass ejection. In this case, we’re seeing the flash, but no cannonball. In either case, we can expect disruptions
in communication here on our planet, because we rely more and more on space-based assets, satellites, in order to communicate
and run our infrastructure.
HARI SREENIVASAN: Put these explosions in perspective for us. One of the places that I read, this is
something like a billion of the nuclear power that we dropped on Hiroshima.
MILES O’BRIEN: Yes, I mean, imagine that. It’s really hard to comprehend it all.
So you can understand why when this energy interacts with the Earth’s magnetic field, it can cause havoc with the
high-frequency communications used by things like the GPS system, or, for that matter, think of the satellite that we’re
using right now to communicate with each other.
If this was in the middle of a serious solar flare or a coronal mass ejection, we might very well be turning to snow right
now. So, we’re vulnerable because of the nature of our infrastructure. And that’s why scientists carefully watch
this. There actually is a fairly sophisticated space weather forecasting capability out there, so that the power grids and
the satellite operators can, if they have to, go into safe mode.
Incidentally, there are residents on board the International Space Station which in some cases might have to take shelter
if a coronal mass ejection was headed our way.
HARI SREENIVASAN: All right, science correspondent Miles O’Brien, hopefully a coronal mass ejection
doesn’t interrupt with this segment. Thanks so much for joining us.
MILES O’BRIEN: All right. You’re welcome, Hari.
The post Oozy
lava and solar cannonballs: Here are two hot spots we can’t extinguish appeared first on PBS