Down 'n Dirty With Interstellar Dust (Transcript) | WAMU 88.5 - American University Radio

Transcripts

Down'n'Dirty With Interstellar Dust

MS. REBECCA SHEIR

13:07:13
But first, let's go up, way up to the stars, though it's not really the stars we're interested in here, per se, it's the stuff in between them. These teensy weensy grains known as interstellar dust, interstellar dust...

UNIDENTIFIED MALE 1

13:07:29
Yes.

SHEIR

13:07:32
What does that even mean?

1

13:07:34
You know, we suffer from the name, just to begin with. You know, you talk about dust and people right away start falling asleep.

SHEIR

13:07:40
But this guy could talk about dust all day long and stay wide awake. His name is Ulysses John Sofia, Professor Ulysses John Sofia.

PROFESSOR ULYSSES JOHN SOFIA

13:07:50
I'm U.J.

SHEIR

13:07:50
U.J. ?

SOFIA

13:07:51
Yeah, Professor Sofia is so...my father.

SOFIA

13:07:56
U.J.'s father, Sabatino, teaches astrophysics at Yale. U.J. teaches at American University.

SOFIA

13:08:01
I'm the chair of the Physics Department.

SHEIR

13:08:03
And he's one of just 200 people in the world studying these tiny grains.

SOFIA

13:08:08
They're sort of the size of particles in cigarette smoke.

SHEIR

13:08:10
U.J. says they clump together in space.

SOFIA

13:08:12
And they're few and far between and most people never know that they exist. And most people don't care about them.

SHEIR

13:08:20
Why should we care about them?

SOFIA

13:08:22
The average person on the street shouldn't. (laugh) So, realistically they do not affect your life in many ways at all.

SHEIR

13:08:32
But before U.J. sells himself completely short, he's a charmingly self-deprecating fellow, you should know these particles aren't just interstellar schmutz. They're the building blocks of all kinds of stuff in the universe from stars to planets, to, well, us.

SOFIA

13:08:47
We have to appreciate dust as the place that we all originated, right? Without dust, we wouldn't be here.

SHEIR

13:08:53
Ashes to ashes, dust to dust.

SOFIA

13:08:55
There you go. I mean, your mother may have said nasty things about dust, but it's good, it's good.

SHEIR

13:08:58
But as to why U.J. has spent 25 years studying this dust between the stars, it has more to do with what a nuisance it is to astrophysicists. See, unlike other sciences where you can sit in the lab, handle specimens, look at slides under a microscope, that sort of thing, in astrophysics...

SOFIA

13:09:17
Everything that we study, stars, galaxies, is extremely far away and the only way that we get information from them is from light.

SHEIR

13:09:23
U.J. gets almost all his data from the Hubble Space Telescope which captures super-detailed images of light from stars. But the interstellar dust distorts that light.

SOFIA

13:09:33
So we aren't getting the proper information about these things that are far away.

SHEIR

13:09:39
For instance, we've all heard about how the universe is expanding, right, like that classic scene from "Annie Hall" where young Alvy and his mother visit Dr. Flicker.

MOTHER

13:09:49
He's been depressed. All of a sudden, he can't do anything. It's something he read.

ALVY

13:09:54
The universe is expanding.

DR. FLICKER

13:09:55
The universe is expanding?

ALVY

13:09:57
Well, the universe is everything and if it's expanding, suddenly it will break apart and that will be the end of everything.

SHEIR

13:10:03
Well, not only is the universe expanding, but in the past 20 years, we've discovered it seems to be expanding faster and faster with time. But some people in the science community say that isn't true. It's the distortion from dust that makes it seem like it's speeding up. So they wouldn't quite say Dr. Flicker was right...

FLICKER

13:10:24
It won't be expanding for billions of years yet, Alvy. We've got to try and enjoy ourselves while we're here, ah? ah? ah? (laugh)

SHEIR

13:10:31
But they would say we have to fix this dust distortion problem so we're not flubbing other calculations and extrapolations about the universe. So how do you fix it? U.J. says you start by figuring out what the dust is made of. But here's the rub. Like we said before, it's far away, too far away to study closely.

SOFIA

13:10:51
So what do we do? Because dust isn't giving us enough information itself, is we look at gas that lives with the dust.

SHEIR

13:10:58
See, together the gas and dust form clouds in what's known as the interstellar medium.

SOFIA

13:11:03
So when you look at the interstellar medium, which you have probably never done before...

SHEIR

13:11:08
That isn't to say I haven't wanted to...

SOFIA

13:11:11
I'm sure everybody secretly does. The gas is mostly hydrogen helium.

SHEIR

13:11:14
In fact 99 percent of all the atoms in the universe are hydrogen and helium.

SOFIA

13:11:18
But those are not atoms that contribute to dust so it's only the 1 percent of other stuff that will clump together in these little solid particles.

SHEIR

13:11:26
So let's say you're looking at a Hubble image of a gas and dust cloud. If you're as astrophysically-savvy as U.J. you'll then form an idea of what's in that cloud, like say, oxides.

SOFIA

13:11:35
We've discovered that there have to be oxides in space. There have to be things like rusty iron in space.

SHEIR

13:11:44
And this iron is in the gas and in the dust so think about it. If you know how much iron should be in the interstellar medium as a whole, you can use the Hubble image to get a read on how much iron is in just the gas.

SOFIA

13:11:56
And if it's not as much as we expect, then we can assume that the part that we're not seeing has clumped together into dust.

SHEIR

13:12:03
The next step in combating the whole light distortion problem is figuring out what those oxides are...

SOFIA

13:12:09
...is the ratio between oxygen and iron in these grains so we can figure out the exact type of mineral and then we can figure out exactly what the distortions are and then eventually correct for that.

SHEIR

13:12:18
U.J. isn't sure when they'll get to the bottom of that mystery, but in the meantime, he has several projects in the works. The first is an unofficial public relations campaign of sorts to raise the profile of his beloved research subject.

SOFIA

13:12:31
When I'm trying to get people interested in it, I usually go with calling it cosmic grains first because cosmic grains sounds much more enticing than interstellar dust, I think.

SHEIR

13:12:43
It also kind of sounds like a weird breakfast cereal we'd have in outer space.

SOFIA

13:12:47
It does kind of and I think people have that picture in their mind and so they get sucked into it so it's all about getting that grab and then bringing people in.

SHEIR

13:12:55
U.J.'s other project involves teaming up with the other Professor Sofia, his dad. They're studying something a little bit larger than those cigarette smoke-sized grains between the stars. The two Sofias are attempting to measure the size and energy variation of the sun. If you'd like to pour yourself a big old bowl of cosmic grains or learn more about interstellar dust anyway, visit our website, metroconnection.org
Transcripts of WAMU programs are available for personal use. Transcripts are provided "As Is" without warranties of any kind, either express or implied. WAMU does not warrant that the transcript is error-free. For all WAMU programs, the broadcast audio should be considered the authoritative version. Transcripts are owned by WAMU 88.5 FM American University Radio and are protected by laws in both the United States and international law. You may not sell or modify transcripts or reproduce, display, distribute, or otherwise use the transcript, in whole or in part, in any way for any public or commercial purpose without the express written permission of WAMU. All requests for uses beyond personal and noncommercial use should be referred to (202) 885-1200.