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NASA Planetary Defense: Asteroid Day Live - Duration: 59:04.
(bold music)
- Take a look,
this is an asteroid observed during
a close approach to Earth,
taken just a few weeks ago using radar.
Asteroid 2014 JO25, came within 1.2 million miles of Earth.
It was a kilometer, or 2/3 of a mile wide,
the largest to come so close to our planet
in the past 13 years.
Hello, I'm Gay Yee Hill, at NASA's Jet Propulsion Laboratory
in Pasadena, California.
NASA takes planetary defense,
and the hunt for asteroids and comets very seriously.
NASA-funded projects account for over 90%
of worldwide efforts to find,
track, and characterize near Earth objects,
that get too close for comfort.
Tiny asteroids hit our atmosphere all the time,
producing meteors or fireballs.
This chart shows the hundreds of significant fireballs
detected by US government sensors from 1988 until now.
It doesn't happen often, but bigger asteroids hit Earth too,
it happened a few years ago.
A 20-meter asteroid exploded in the atmosphere
above Chelyabinsk, Russia.
So, it's important to be on the lookout.
To start things off, let's give you a simplified explanation
of how we hunt for space rocks.
- [Narrator] How do we spot near Earth asteroids?
To start, survey telescopes scan the sky.
When multiple pictures of the same spot
show a speck that's moving, computers automatically check it
against a database of known objects.
If there's no match,
it gets added to a list of objects to confirm.
And if it looks like it'll pass very close to us,
we give it top priority.
Then it's time to call in reinforcements.
More astronomers from NASA, other institutions,
and even the amateur community,
submit additional observations.
Each new data point
helps refine the projected path,
and this asteroid
is gonna fly right on by.
All the info will be posted online,
so it can continue to be tracked and monitored.
Nice work planetary defense team.
Keep watching the skies.
- Now NASA is directed by Congress to find 90% of asteroids
460 feet, that's 140 meters, or greater in size.
NASA's Planetary Defense Coordination Office
is responsible for finding, tracking,
and characterizing potentially hazardous
asteroids and comets coming near Earth.
Lindley Johnson is the agency's Planetary Defense Officer,
and Kelly Fast is the Manager of the
Near Earth Object Observations Program.
They join us now,
live from NASA Headquarters in Washington DC,
where all NASA planetary defense efforts are managed.
Hi Lindley, hi Kelly,
Let's start out with a question--
- Hi. - Hi.
- Let's start off with a question for Lindley.
What exactly is NASA doing to protect Earth
from dangerous asteroids and comets?
- Well Gay, that's the whole purpose behind
our Planetary Defense Coordination Office,
is to oversee the efforts of NASA
in our observatories that are finding,
tracking, and characterizing near Earth objects.
And to work with other government agencies
to develop a response if we happen to find one that is
on an impact trajectory with the Earth.
We work with the Federal Emergency Management Agency
and other government agencies to develop the plans
and the strategies that would be used
to respond to a detected impactor.
But the most important part of our business
is to find them, we have to find them
to be able to do anything about them.
So our main priority is to find them
as early as we can and that's what
the near Earth Object Observations Program is all about.
- All right, so question for Kelly.
How are we finding them?
- Well Gay, NASA funds observatories to survey
the skies each clear night to try to find
these near Earth objects, to discover them.
And then we also fund a number of astronomers
to follow up those discoveries to try to get
more observations of the positions of those objects
to better understand how they're moving.
Now all of those observations from the people we fund
and anybody observing around the world
go to the Minor Planets Center where they catalog
and keep all those observations,
but also they do a calculation of the orbit
based on how those objects are moving
to try to figure out where it's going to be in the future
and if there is a near-term impact risk to Earth
they will let NASA know about it.
Now also, JPL's Center for near Earth Object Studies,
they also take those positions, those observations
and they do precision orbit calculation,
looking at where those asteroids will be
in the near term but also into the future,
decades into the future.
Because if there was something that posed an impact risk,
you'd wanna know about it well ahead of time
so that you could plan your response to it.
- And Kelly, are we alone in this whole process?
Are other countries involved at all?
- Oh yeah, there are other countries involved and in fact,
there is an International Asteroid Warning Network
that is a UN-sanctioned group
and NASA is a signatory to that group.
And it's a group involving space agencies,
national institutes, and observatories
that coordinate on the search, the discovery,
follow up, characterization, and orbit determination
for these objects so that we have all the information
that's possible out there contributing to the task.
And so yes there is significant international participation.
- Lindley, one more question.
If there is a dangerous asteroid
and it's on a collision course with Earth,
can we really do anything about it?
- Well, that would depend on how big it is
and how much time we have before the predicted impact.
We would assess the size of the object
and try to determine what the mass is,
and that would determine what techniques
might be able to be used on it.
And we have, as part of our program,
developing those kind of capabilities.
But it all depends on how much time we have.
If we only have days or weeks,
that's not enough time to mount a space mission
to deflect it in space, and so we would just have to
prepare with FEMA to take the impact,
if it was on US territory.
So the key to our program is to find em early.
- Alright, so we have just a few more minutes,
and I'd like to take some time
for a couple of social media questions.
I have one for Lindley first,
David and others on Twitter are asking,
are there any near Earth objects
that post a danger to Earth?
- Well of the catalog that we have now,
over 16,000 near Earth objects,
there's none that have any significant probability
of impacting the Earth.
Yes, there are objects that will come near the Earth,
but our already determined folks out there,
JPL as a matter of fact,
have shown that the probability of any of those
is really low.
So there is no immediate threat to the Earth
being impacted by the objects that we know about.
But we have a lot more of em to find.
- Alright, here's another one, this one's for Kelly.
Lisa on Twitter wants to know,
if there was an asteroid headed for Earth,
would we be told or would NASA keep it quiet?
And Kahleed asks, would you Tweet it?
- Oh absolutely the public would be told,
in fact it wouldn't be possible to keep it quiet
because we coordinate with astronomers
all over the world, over the internet,
and so the information would be out there.
And also all of the observations, as we've said,
go to the Minor Planet Center,
and it's on their website,
and then the predictions that are determined out at
the Center for near Earth Objects Studies at JPL,
it's on their website.
So the information is out there,
and we have a communication plan here too at NASA
to communicate within our government
and with other governments so,
absolutely this would go out to the public
and eventually it would end up on Twitter, too.
- Alright, so Lindley, Kelly thank you so much,
we will be checking with you again later on in the show.
And you can find out more about
NASA's Planetary Defense Coordination Office
by going to nasa.gov/planetarydefense.
(upbeat techno music)
As you hear earlier, NASA has to be on a constant lookout
for potentially hazardous space rocks.
The goal is to discover them early enough
to be able to do something about them.
On average, NASA sponsored projects
spot about five near Earth objects a night,
and fine tune the orbits of many more.
NASA has adapted the NEOWISE Space Telescope
to survey the skies,
but the real workhorses are unique ground telescopes
at the Catalina Sky Survey on Mount Lemmon, Arizona,
and the Panoramic Survey Telescope
And Rapid Response System, it's called Pan-STARRS,
located on Haleakala, Hawaii.
(dramatic guitar music)
- Catalina Sky Survey and other survey programs,
are really sort of the start of the whole
planetary protection ecosystem.
It starts with discovery, it goes onto followup,
and characterization, impact risk analysis,
mitigation studies, but you can't
follow up, and you can't characterize,
and you can't calculate the impact risk
of something you don't discover.
In order to find and near Earth asteroid,
we take four images of a patch of sky,
separated by about five minutes.
- And we take those four images,
and we blink them really fast,
and it creates this little animation
so we can see that the stars in the background
are static, as they should be.
And if there's anything that's moving, it'll pop out.
- And our software compares those images,
and identifies things that are not moving,
which are stars, and removes those.
Identifies things are transient from frame to frame,
and tries to link those up.
(thoughtful music)
- We've probably seen about a million asteroids
in the last seven years that Pan-STARRS has been operating.
It's like picking a needle out of a haystack.
We're looking for distinctive motion,
and when we see distinctive motion in asteroids,
we report them to the Minor Planet Center.
The Minor Planet Center is the sort of
world clearing house for near Earth asteroids.
- The Center for NEO Studies takes these observations
from the Minor Planet Center and computes
the high-precision orbits that we use to make predictions.
CNEOS is also kind of an early warning system
for newly discovered asteroids.
We take the early data, and we compute whether or not
that asteroid could hit the Earth.
If there's a chance, we'll send out an early warning,
an alert, for followup observations
so that we can get more data and then we would know perhaps
whether it can hit the Earth or not.
- Asteroid impacts are a fact of life.
The Earth has been impacted by asteroids
continually through its history.
- We saw in 2013 in Russia, a fairly small,
by the standards of what we're finding,
asteroid did hit the Earth.
I feel a little bit like a guardian of the planet,
I'm doing my bit to try and protect people.
It is a long term process.
It's going to take many, many years to find
all of the dangerous asteroids.
- The goal is to find near Earth asteroids
before they find us.
- Well tracking asteroids takes a worldwide effort.
Here's a map of NASA-sponsored projects,
but there's more to it than this.
Add in all the observers, amateurs,
and professionals all over the world and now
there are hundreds of additional eyes
looking for asteroids all around the planet.
These observers report their asteroid sightings
to the Minor Planet Center in Cambridge, Massachusetts.
That is a key player in planetary defense.
The Minor Planet Center shares the information
with astronomers worldwide about
potentially hazardous objects.
This allows for multiple observations of the same asteroid.
Matt Holman is the director of the Minor Planet Center,
and he joins us live now, hi Matt.
- Hi Gay.
- Alright so you told me earlier,
this is all about following all the dots.
So tell me exactly, what is the MPC?
- The MPC, or the Minor Planet Center,
is the world's clearinghouse for asteroid observations.
We get observations of asteroids from hundreds,
even thousands of different observatories,
and we collect all those data together,
distribute it to everyone who needs it,
or anyone who's interested.
But we're also busying ourselves trying to determine
which of those asteroid observations correspond
to something that urgently needs followup observations.
- Well tell me why you even need
a clearinghouse for all of these objects?
Why is it necessary?
- Well there's so many people involved,
it really would not be efficient to have them
try to distribute their data to each other.
It's much more efficient if they just sent it all to us,
then we can bring it together and we're trying to see if
people have incidentally observed the same object,
and you can then collate those data
and very quickly feed it back to them,
to say okay, these are the things that need
even more observations.
- Alright, so it's a central contact
so you work more efficiently.
Can you go ahead and just walk me through the process?
How does it all work?
- Well on any given night,
the Minor Planet Center receives
something like 100,000 individual observations of asteroids.
And we ask ourselves immediately this question constantly,
which of these observations correspond to an object
that we've seen before?
And which of them correspond to something
that's a new discovery,
potentially a hazardous near Earth object?
And believe it or not, 90% of the time,
we know what those objects are,
we've seen them before and we have
very precisely determined orbits.
We can take those 90% and set them aside,
and focus our attention on the remaining 10%
to try to determine if those are
potentially hazardous near Earth objects,
or a garden variety main belt asteroids.
- So how do you tell the difference
between the main belt asteroids, which are far, far away,
and the ones that are actually kind of close?
- Well as Richard Wainscoat kind of suggested,
we use the pattern of motion on the sky.
Let me give you an analogy,
so imagine you're in a car and you're driving along the road
and you look out the window,
and you look at the fence posts.
Those fence posts will appear to be moving
very, very quickly.
If you look at the trees behind the fence posts,
they'll appear to be moving less quickly,
and if you look at the mountains way in the background,
they won't appear to be moving at all.
In fact, none of those things are moving,
it's the car that's moving,
and the apparent rate of motion is a proxy for distance,
the things that are close to you
appear to be moving more quickly,
and that's really what's going on with asteroids too.
It's something we call paralax,
so the set of dots that are really moving quickly
along the sky, those are very likely to be things
that are pretty close to the Earth,
and that's what we concentrate on.
- So if you find something that needs
a little bit more double checking,
how do you tell your observers?
- Well we have something called the NEO Confirmation Page.
It's a website that the Minor Planet Center
is constantly updating, and so that's where
we maintain a prioritized list of objects
that need additional observations.
- Well we learned a lot Matt,
thank you so much for joining us.
- My pleasure.
- And if you would like to learn more,
you can check out the Minor Planet Center,
the website that is, it is minorplanetcenter.net.
(upbeat techno music)
October 6th, 2008, was a day
when NASA's asteroid hunting team was put to the test.
The Catalina Sky Survey team spotted an asteroid
that eventually would hit Earth, just 19 hours
before it was predicted to enter the atmosphere.
The Near Earth Objects team and astronomers
all over the world sprang into action.
Their observations allowed us to figure out
exactly where and when the object would hit.
At only a few meters across, it posed no danger,
it was small and posed no threat.
On October 7th, 2008, with officials alerted,
Asteroid TC3 plunged through our atmosphere
and exploded 23 miles above the remote desert in the Sudan.
Hundreds of meteorites were later recovered.
Now this was the first time an asteroid was spotted
and its location calculated prior to
hitting Earth's atmosphere.
The system worked.
NASA's Center for near Earth Object Studies,
here at the Jet Propulsion Laboratory, played a big role.
The center computes high precision objects
of near Earth objects and predicts the future path,
and assesses whether or not
they'll actually impact the Earth.
Paul Chodas is the manager of CNEOS.
What was that day like for TC3?
- That was an exciting day, believe me.
And it was all compressed into a single day,
because it was discovered, we had to run the numbers,
we had to realize it was going to hit the Earth,
and then we had to figure out where
it was going to hit the Earth,
notify people, and encourage more observations,
all compressed into one day!
Fortunately, we knew it was small.
That was the first question to ask,
and we could see that it was small.
- But it must have been just gathering together
and picking up the phone call and hearing,
I mean you guys just jumped on it, everybody.
- Yeah all the teams did, the Minor Planet Center,
our team, and Lindley Johnson of course was involved
in communicating this to the higher ups
at NASA and in our government.
So it was a busy day for everyone.
- Why do you say that this was a real test,
and you guys passed?
- Well our calculations early on
indicated it would hit in the Nubian Desert in Sudan,
and so we identified the location early,
and as we got more and more observations,
we identified even the ground track so well
that two months later when some astronomers
went out to look for the meteorites, we told them
exactly where to find them. - Wow!
- There they were, right on the path.
- Okay so it is the job of CNEOS, over the center,
to figure out the orbit.
And I think we should also explain to some people,
some people don't realize that
near Earth objects are orbiting the sun just like Earth is,
and what you're figuring out is
the orbit of this body and whether or not
it'll one day intersect with Earth's orbit.
- That's right, near Earth objects
orbit the sun, just like the planets,
and they're on ellipses, and sometimes some of those
ellipses come very close to the Earth's orbit.
If there's an intersection of the orbits,
then the next question is, well will the Earth
ever be there when the asteroid gets there?
And that's kind of a very precision calculation
that we have to run, and we want to do that
many decades into the future.
Apophis was an early example of that.
Back in 2004,
the orbit of Apophis
looked like there was a chance that Apophis,
which is a large asteroid.
- [Gay] I remember that!
- You remember that?
- It was 1,000 feet across.
It looked like in 2029 that there was a chance
that it could hit the Earth at that intersection point.
And we were worried the impact probability
kept getting a little higher and a little higher
as we took more and more observations.
- So let's take Apophis as an example.
Very early on, I remember hearing the reports,
oh it looks like there's 4% chance that it could it.
And then, as the time went by, then oh maybe not,
and then finally there was a report saying absolutely not.
Was NASA wrong at the start?
- No, because we add data.
We get more and more information.
We make our projections, it's kind of like
shining a flashlight actually.
- [Gay] And we have an image that we can probably put up.
- [Paul] Yeah, yeah, so we would say,
here's what it looks like in 2029.
We think the asteroid could pass
somewhere within the ellipse,
and look the Earth is within the ellipse.
We get a probability - Okay.
- Maybe it was 2% there, and then a day later
we get a little more data, and the next step,
there's another ellipse and look, it's even more likely
to hit the Earth as you get more data, 4% now.
But then we found some more observations,
actually in the archives of Apophis,
and we ran the calculation again,
and we get an even more precise prediction
and now look, the Earth is no long inside the ellipse,
so it can't hit.
- So it's a matter of getting more and more information.
How do you get that information to dial in the orbit,
and get a more exact idea?
- What I like to say is, we take all the numbers
and we plot the path, you know.
And so we're trying to see in the future
how close it can come, basically.
We're plotting the path.
We're running the numbers in high precision.
- Alright so when you're running the numbers
on all these sightings that are coming in every single day,
how do you figure out and how do you give an early warning
to folks and flag them that,
oh this is something to keep an eye on,
oh that's not gonna be a problem for at least 100 years.
I mean how do you do that?
- Well we calculate a probability,
and we have two systems to do this.
One is what we call a sentry system,
which runs a very long term, 100 year calculation,
running the numbers and seeing how close
the asteroids could get.
We have a short term system for the NEOCP,
the Near Earth Object Confirmation Page
that Matt just mentioned.
These are for brand newly discovered objects,
that just got discovered and very little data,
but we'd like to know.
Objects are usually discovered
when they're close to the Earth.
Could it hit the Earth?
You know even before we've even confirmed the object.
So that's a short term impact hazard calculation,
that's the SCOUT system.
So we run the numbers both in short term and in long term.
- Alright and you keep track of all the sightings
and we can actually put up the number
that you have sighted so far.
- Well this is NASA,
and in fact the entire catalog
is now at 16,245 asteroids.
That's the blue graph there.
In 2017, which will be on the right axis there,
you can see we're past 16,000.
We're seeing them at about 1800 per year right now.
- Wow.
- Now some people are concerned, they say look how fast
we're discovering them, why are all of a sudden
asteroids hitting the Earth?
That wasn't happening before, was it?
It was, it was, we're just getting better at finding them.
So we want to keep that discovery rate increasing.
- Alright, well I have a social media question for you.
Bob wants to know, how exactly do you know the size
of passing asteroids?
- They're only a point of light in these telescopes.
- [Gay] Absolutely.
- So all we know is how bright they are.
So we have to assume a certain reflectivity,
we're seeing them by reflected light.
So we assume they're kind of as reflective as 14%
of the sunshine is being reflected.
So we calculate a rough size, just based on brightness.
- Alright, well thank you so much Paul.
And we have a website for you if you want more information
on CNEOS, go to cneos.jpl.nasa.gov.
(upbeat techno music)
NASA relies on trusted astronomers
to do followup observations to confirm
if a near Earth object is really there,
and to help us refine the orbit.
One followup observer is Robert Holmes.
Bob started as a volunteer observer,
but he's so good, NASA now pays him
to hunt asteroids full time.
He's one of the world's most prolific observers.
How does he do it?
We went to his home in Illinois farm country to find out.
(easy guitar music)
- We do followup observations,
with NASA's near Earth Observations program.
All night long, I'm running big telescopes.
One's a 24 inch, a 30 inch, and a 32 inch.
And then the 50 inch is my biggest telescope.
Having four telescopes allows me,
really to do four times as much work
as the typical observatory that just has one telescope.
So it is a huge advantage.
I work on a nightly basis
and I use these telescopes to look at asteroids.
We do followup observations for the discoveries
that are made by the large sky surveys.
By looking at these asteroids and measuring these asteroids,
we can determine what their possibilities
of actually hitting the Earth in the future are going to be.
NASA provides coordinates of specific objects
that they need observations on.
I'm going to punch in the coordinates here.
And I'm doing this remotely from inside a control room.
Not at the telescope.
And so we look these objects up,
and then use those coordinates to look at
a tiny piece of the sky that this object happens to be in.
And then we follow those objects
and define and refine orbits for those objects,
and we do see uncertainty of where it's going to go
in the near future.
I started off as a volunteer in 2006.
It's just blossomed into a full time opportutnity
to work for NASA under their grant program,
where I'm now doing this every single clear night.
You know we're start the observing run for
2017 KK3.
You don't build a telescope that's this big
without being passionate about what you do.
I'm really driven to be a part of a program
that's important and has importance to the future.
And we're not talking about next year or the year after,
we're talking about asteroids that could
potentially hit the Earth 100 years from now.
And the work we do today
may make a difference 100 years from now.
- Like Bob Holmes, the Magdalena Ridge Observatory
does followup observations.
It's located 10,600 feet in the mountains
near Socorro, New Mexico.
Magdalena also characterizes asteroids.
How fast the asteroid is spinning,
what kind of shape it has,
and what's it made out of, how big is it?
The observatory has a fast telescope
capable of tracking rockets, asteroids, even space junk.
Eilene Ryan is the Director of the telescope,
and she joins us now via Skype, hi Eilene!
- Hello Gay.
- So explain to me this fast telescope.
What do you mean by that?
I mean can it whip in a direction
and track something really quickly?
Is it the F stop, what are talking about?
- Well actually we're talking about the telescope motion.
It can move 10 times faster
than a normal astronomical telescope,
and that's pretty fast, so we are at an advantage
when we're looking at asteroids that come
very close to the Earth because they can also
move very rapidly through the sky.
So if we want to demonstrate this,
we can watch a movie that we took
of an asteroid that came very close to the Earth
in November 2015, Asteroid 2015 VY105.
So the bright central dot in the movie is
what our 2.4 meter telescope is locked on and tracking.
And as you can see, the streaks that are going by,
they're background stars that the asteroid
is rapidly speeding by, so pretty fast.
It's pretty amazing that we can look at this,
and analyze close-approaching asteroids,
but what's most interesting about the movie,
if you look at the final frame of the movie,
we have captured Asteroid VY105
coming so close to the Earth, that it actually
passed through our geosynchronous satellite zone.
So if you watch the movie for the final frame,
you can see an odd angled streak at the bottom of the frame.
And that's not a star streaking by,
it's actually one of NASA's communication satellites.
So the asteroid passed very close by this satellite
as well as several others, but luckily it didn't hit.
- That was very close.
But as you mentioned, you know we're look at it same as you
they're just little points of light.
How are you able to get any characteristic information
on something so small?
- Well it's actually pretty fun and amazing
to realize how much we can learn from a point of light.
One of the things that we study, and we specialize in at MRO
is looking asteroid rotation rate.
So asteroids spin on their axis as they're moving
in their orbit around the sun.
And so here I have model asteroid,
and you may have noticed it's not very round.
Most asteroids are potato shaped or irregularly shaped,
but if we use this model to examine
how could we find from a point of light,
or light variation, a spin rate?
Well, asteroids shine by reflected sunlight,
so here as they rotate, and this model asteroid,
and you can see the surface area is changing.
So we might have a little bit of light
reflected back to the instruments on our telescope
when the asteroid is in this position.
And then we get a lot of light, a little bit of light,
a lot of light, and a little bit.
Let's look at this next movie and we can see this
schematically represented by
an egg shaped asteroid rotating.
You can see as the asteroid rotates,
the light is changing and we get two peaks and two dips,
which represent a rotation cycle.
This is usually referred to as a light curve,
this changing brightness.
And when we go through this whole cycle,
we get one rotation rate.
So we can have asteroids spinning as short a time
as tens of seconds to many, many hours,
but we can look at this and analyze the asteroid
to understand potentially its strength,
whether it's a rubble pile or an intact object.
And we look at the peaks and dips to see
if we can also infer the actual shape of the asteroid.
- I remember once when we were first talking,
that you see these flybys as a mission coming to you.
That you know we work so hard to send space craft
far, far away to explore comets, and asteroids, and planets,
but here is this wonderful moment where they come to you
and you're saying that you're hitting it
with everything you've got.
And so you have - That's right!
- Many instruments, what else do you find as this thing
is just swinging by you,
what more information can you gather?
- Well, we can also do, in addition to spin rates,
we want to get everything, as you said,
while we have it in our sights.
So we can look at an asteroid
and also determine its composition.
One advantage we have at MRO is that
we can mount multiple instruments at the same time
on our telescope, so we can easily switch
from a light-changing instrument,
to something called a spectrometer,
which will separate the light into different wavelengths
and we can then analyze and get a fingerprint
of the particular composition of an asteroid.
So asteroids can be metal, rock, or combinations of the two,
and as Paul Chodas mentioned earlier in the broadcast,
when we know overall reflectivity based on the composition,
we can get an estimate of size, which is very important.
And specifically, different types of asteroids,
different compositions, would require different approaches
for deflection if we ever found a hazardous one
that we needed to so something about
while it was still in space.
So a very vital information characterization
and an important practical role it can play.
- So getting as much information as you can,
so you know what you're dealing with?
- [Eilene] Absolutely.
- Alright well I understand you told me
that there is a little side story that you have
a mirror that you use, it's got a little bit of a legacy,
a little bit of heritage there.
- Actually it's pretty exciting.
Our telescope mirror is actually one of two spares
leftover from the Hubble Space Telescope program.
So we have the only working spare
incorporated into our telescope,
the other spare went to the Smithsonian Museum
in Washington DC after it wasn't needed for Hubble.
So we feel very honored to have such a mirror,
and it performs absolutely beautifully,
and so New Mexico Tech University,
which runs Magdalena Ridge Observatory
actually got it for free.
- Wow, great story.
I have a social media question for you, Eilene.
Here it is, many out there on social media want to know
when there are close approaches by passing asteroids.
Can you see them with your naked eye?
- Sometimes you can, it depends on how bright they are.
Most of the time that we needed
even just a small backyard telescope.
Naturally if you went outside and you looked
in the night sky you might see things
of a visual magnitude of five or six,
even asteroids that come very close to the Earth,
we might even have them being
as bright as 10 or 12 on our brightness scale.
So you can see them through,
sometimes your backyard telescope,
sometimes they're very faint still
and we need big telescopes like our 2.4 meter telescope
to actually study.
- Alright Eilene, always a pleasure to talk to you.
Thank you so much for helping us out today.
- [Eilene] Thanks Gay.
(upbeat techno music)
- At the start of the show, we showed a radar movie
of Asteroid 2014 JO25
made using the 70 meter antenna
at Goldstone Station in the Mohave Desert.
The antenna is part of NASA's Deep Space Network,
which communicates with our space craft
across the solar system, from this room in fact.
But that communications disc is actually
a terrific scientific instrument as well.
Using it for radar gives us a chance
to see asteroids in great detail.
Let me introduce you now to radar scientist,
Marina Brozovic, here at NASA's Jet Propulsion Laboratory.
Hi Marina!
- Hi.
- Okay, explain to us how radar works, in the first place.
- Well our planetary radars are very much
like the airport radars that track airplanes in the sky.
But airport radars, they track airplanes that are within
60 mile radius, and our planetary radars reach much further.
So we are tracking near Earth objects
that are hundreds of thousands,
sometimes more than millions of miles away from Earth.
And for this you need
really powerful transmitters and very large antennas,
such as, there is a 300 meter dish,
Arecibo, in Puerto Rico, and then we also have
our 70 meter, the SS-14 antenna at Goldstone.
And so let me show you, there is a like a brief animation
of how radar really works.
So it transmits radio waves, and these radio waves,
they bounce off the asteroid.
And the echo that comes back carries
a lot of information about that asteroid.
So for example, when we observed Asteroid Apophis
during 2013 flyby, there is a video showing
how we zapped the asteroid as it was going by.
We zapped it with radar, and we basically wanted
to very precisely measure where it is
and how fast its moving.
And we use these measurements
in order to improve our orbital calculations,
because better data means better orbits.
- So what does radar then bring to the table?
- Well radar is a little bit like a Swiss Army knife,
because it reveals so much about asteroid at once.
You know in optical telescopes,
asteroids are these specks of lights,
but in radar images, they become worlds of their own.
And you can see all these details in them,
so in the radar images you directly see
how asteroid looks like.
If it has a satellite, how large it is.
How it's rotating, and we can even see
surface features on it.
So we see ridges, and facets, and concavities,
and boulders, and basically all the nooks and crannies.
And we have such example,
there is a video you already showed,
this asteroid we observed a couple of months ago,
2014 JO25, so it turned out to be
this 2/3 of a mile long space peanut.
And we were just watching it rotate in front of our eyes
during four eyes of radar observations,
and it's fasincating that you could see
how this front lobe is casting radar shadow
and the back lobe, and you can see
all the concavities and ridges,
and if you look very carefully,
there are these radar bright specks
that are rotating with asteroid,
and we believe that these are meter-sized surface boulders,
and all this is visible while the asteroid
was 1.8 million miles away from Earth.
- Well it's interesting, sometimes you can even see
if there's more than one asteroid, and they're together!
- Yes, these are binary asteroids, and now we know,
thanks to radar, and optical telescopes,
we know that one in six asteroids in near Earth population,
asteroids that are larger than about 140 meters in size,
they have a companion.
We even found two triple systems.
So there are actually - Wow.
- Two asteroids that we know of, that have two satellites.
- Alright, so all of this focus has been
on getting an understanding of an asteroid
that may be coming to us, headed this way.
But could we use this information to help us
if we want to go exploring asteroids?
- Absolutely, so radar observations,
they have been used in the past
to support space craft missions.
And in fact, Mission OSIRIS-REx,
that it's on its way to rendezvous Asteroid Bennu in 2018,
has definitely benefited from
the existing radar observations because based on that
we had a full reconstruction of Bennu's shape,
we had an estimate of its size,
of its spin state, and even mass.
And you can imagine all this information is really useful
when you are planning proximity
space craft operations around asteroid.
It just gives you kind of level of safety for the mission,
and it also allows for you to better plan
the scientific observations.
- Okay, I have a social media question.
And this one is someone who's trying to understand,
why do asteroids have these odd names,
like 2014 JO25, why don't you call it Madge?
(laughing)
Why do you have these names?
- Yeah so there is actually a good reason for it,
so Minor Planet Center assigns these temporary designations
and they mean something to us.
For example, 2014 JO25.
2014 means it was discovered in 2014.
Letter J tells me that it was discovered
in first two weeks of May.
And then O25, there's a little formula.
That tells me that it was 639th minor planet
that was discovered in that two week period.
So there is a method to the madness.
- Alright, so when people see that, 2014 2025,
they understand.
- Yes, there is actually meaning.
- Thanks Marina.
- Absolutely, thank you.
(upbeat techno music)
- We mentioned NASA's NEOWISE space telescope earlier.
NEOWISE is a space telescope,
now it was originally designed to image the sky
in the infrared spectrum, that is the spectrum
that detects heat.
Now originally this was the WISE telescope,
and it was sent to survey the skies.
Then it completed its job and it was mothballed,
and then it was realized that maybe it was very good
at detecting asteroids.
So then it was taken out of mothballs
and became the NEOWISE Mission,
in which it allowed us to actually search for asteroids.
It's focus now to characterizing and finding
near Earth asteroids.
It turns out that infrared is just a great tool
for hunting space rocks, especially the dark ones
that are difficult for the ground telescopes to spot.
Amy Mainzer is the principal investigator for NEOWISE,
Amy can you explain to me why this is such a great tool,
why is infrared so great?
- Thanks Gay.
Well one of the great things about using
different wavelengths of light to study these objects,
is that we learn something different and unique
from each new way that we look at it.
We just heard about how radar provides a whole array
of useful information about asteroids.
Infrared light is different from both
visible light and radar in terms of what it returns to us.
With visible light, we're seeing light bouncing
off the surface of asteroid and coming into our telescopes,
so we're very sensitive to the properties of the surface.
If the surface is really dark,
it's harder to see with visible wavelengths.
Whereas--
- [Gay] And so Amy, we actually have an infrared camera
in the room with you, and so what is it doing?
It's just detecting the heat?
- Yeah, that's right.
So what you're seeing is the heat that's coming off of me,
you can see that my nose is cold,
my fingers are a little cold,
but this I the kind of imaging
that we use with the asteroids.
And we look for them using their heat signatures.
So this lets us see them regardless of whether
they're kind of light in color on their surfaces,
or darker in color on their surfaces.
- [Gay] And how is that helpful
in terms of being able to spot the asteroids?
- Well there definitely are asteroids out there
in the population that we know
that are made of carbonaceous materials,
as opposed to lighter colored stony materials.
These really dark colored objects
are harder to spot with visible light,
but if we look for them with their heat signatures,
using infrared telescopes, like NEOWISE, they pop out.
- Alright, so tell me more about NEOWISE.
I tried to relay this story about,
that it wasn't originally sent out there
to look for asteroids.
- That's right, the original mission
is the Wide-field Infrared Survey Explorer mission.
And the principal investigators, Dr Ned Wright of UCLA,
and the mission was originally designed
to survey the whole sky in infrared light,
to search for very bright galaxies
and very cool stars, it did that beautifully.
It finished its prime mission successfully.
But in the process we found that it was
quite effective at spotting asteroids,
particularly these very dark objects.
So when the mission was completed in 2011,
we thought that was the end of the story.
But we were lucky, we were able to bring it back to life.
- Absolutely not, we have a graphic that I can pull up,
and it shows all the discoveries that NEOWISE has made.
How many discoveries has NEOWISE made?
- Yeah so the graphic shows you
the asteroids that we've detected
since the restart of the mission in 2013.
So if we include the prime mission
as well as the restart years,
we have a total of around 34,000 new discoveries.
- 34,000, alright so we obviously have shown
that this technology works, so what do we see ahead
as future technology?
Kind of maximizing on what we've learned.
- Right, well one of the great things about
having gotten to use this spacecraft for a new purpose,
which is to search for asteroids and comets,
is that we've learned a great deal about
how do to do this work using a space based telescope,
an infrared telescope, for discovery in large numbers.
Now the thing is, NEOWISE was never
originally designed for this purpose,
and all good things are going to come to an end.
Eventually the mission is going to end.
It was not designed to last this long.
And it really wasn't designed from the get-go
for searching for asteroids.
However we've been looking for new ways
to search for asteroids using a space telescope
that is designed for this purpose.
And we call that the Near Earth Object Camera, or NEO-Cam.
- [Gay] Alright, and there is a picture of it.
- Right so it's basically designed to go out
and spend all of its time searching for
asteroids and comets that could potentially
get close to the Earth.
And the main difference from NEOWISE
is that it's going to have a longer lifetime,
it can search a much wider area of the sky,
and it has modern, next-generation detectors.
So basically these are the camera chips
that are capable of sensing the asteroids
at the wavelengths where they're really bright,
which is infrared.
- Perfect, well I have a social media question.
And we have gotten several about how things are named,
and I understand that you have been involved
in naming asteroids in the past,
after women who were very strong.
- You know one of the great privileges
of discovering the asteroids is that we do get to name them.
The discoverer has, the IAU allows us to propose names
and submit them and if they approve them,
then that's the name of the object.
There's some just really fantastic people out there
who I think deserve asteroid names.
- Give us some examples.
- Well, Malala was one, and actually
one of my colleagues, Dr Carrie Nugent, over at Cal Tech,
and I were talking about her and were just like
man she is amazing!
She needs an asteroid. (laughing)
- Well yes, that is a great perk.
Thank you so much, Amy.
- Thank you, Gay.
(upbeat techno music)
Okay, so what if we identify an object
that actually is headed our way?
NASA has to deal with that too.
Let's check in with NASA's Planetary Defense Officer,
Lindley Johnson and Kelly Fast,
Manager of the Near Earth Object Observation program.
So Lindley and Kelly, we have plenty of time right now,
and let's look at this step of the whole phase
that you have to deal with.
I mean first of all Kelly,
say an asteroid is headed for Earth,
would we tell the public about it?
People seem to really be concerned about that.
- Yes Gay, we would tell the public
because first of all the data are public.
The observations go to the Minor Planet Center,
the orbit determination shows up on the websites there,
and on the Center for Near Earth Object Studies.
So the information would be out there to begin with,
but first of all we'd want to a confirmation.
At NASA we'd want to work with our partners
in the International Asteroid Warning Network
to look at orbit determination and to look at
the risk of impact and the effects of the impact
and to make sure that everybody is on the same page,
or getting consistent answers.
To have that verification
so that the most accurate information is going out there.
And then also at NASA there is a notification procedure
in place where there would be a notification
that would go up through the NASA administrator
to the White House and on to other US agencies,
onto Congress, and also ultimately to other countries.
And so yes it wold become very public very quickly
and so we would just want to make sure
that it happens in the right and accurate way.
- Alright so people should be rest assured
that that information would never be withheld.
- Right, that's correct.
It really wouldn't because again,
the information is on websites,
and people with the right telescopes,
I mean the skies are open so they can look themselves.
- So the next question goes to Lindley,
what happens next, if you do see something
that appears to be, going to able to impact the Earth?
- Well Gay, that all depends on how big it is,
you already shown us an example of 2008 TC3,
a very small object, that we knew that
the Earth's atmosphere would protect us from it,
so we weren't too worried about it.
We just wanted to determine where it was going to impact,
what time, so we could go out and collect all the meteorites
as you saw because that's a very valuable
resource for the scientist to learn more about asteroids.
So it's kind of a free sample return, so to speak.
But if it's a larger object,
say a few tens of meters in size,
that's where we have to get
the other federal agencies involved and their counterparts
around the world to first of all,
determine where on the Earth it's going to impact,
so that we can alert them.
One thing about predicting asteroid impacts is
that we can determine precisely the time
that they're going to impact,
and with observations as it comes in,
we can determine a location very accurately too.
And so this is kind of a unique thing
for FEMA and the other emergency response community,
is that we can tell them the time and location
of a potential disaster before its gonna happen
so that was very valuable information for them
to prepare the area,
the community that might be affected by it
so that populations can be evacuated
and infrastructure locked down.
Now if it's bigger than that,
and this is actually our main objective at
the Planetary Defense Coordination Office
and all of the projects that we work with,
all that you have seen today,
is to find an object that is large enough
that it could affect a major metropolitan
or a statewide area, find it far enough out in time
that we have time to initiate a space mission
to go out an deflect it off of that impact trajectory.
So we are looking at various techniques and technologies
like a kinetic impactor or a gravity tractor,
that we could send out several years in advance
to prevent the impact in the first place.
- So let's take that as an example,
Kelly if there was something as big as a football stadium,
is that something that can be dealt with?
- Well actually I'm going to kick that one
to Lindley and let him address that.
- If Lindley if it's as big as a football stadium,
is that something that we have even thought about?
- Oh yes, that is the type of scenario
that we are mainly looking at,
because the most common hazardous asteroid
that we might have to face with
that we'd want to deflect in space
is the size of a few hundred meters or so,
and if we find it several years in advance
and are able to get space missions out to it,
an object of that size, we only have to change the speed
of the asteroid by a few centimeters per second,
and if we do that several years in advance,
it will not reach the same point in space as the Earth
at the predicted impact time, we will have slowed it down
and so the Earth will have already
passed that point in space.
So that is a principle that is used
in all of our various mitigation techniques.
So the kinetic impactor, we just hit it hard,
with a space craft that knocks off
a few inches per second speed in its velocity,
and causes it to be a miss instead of a hit.
The gravity tractor operates similarly,
in that the mutual attraction
between the space craft and the asteroid over time,
slowly, using nature's tug rope gravity,
slowly tugs that asteroid off of the impact trajectory
and then prevents it from impacting the Earth.
- So we have just a few minutes left,
if we could talk about that in our last three minutes.
The fact that asteroids are a natural hazard,
and from what we're hearing all throughout this program,
it's a natural hazard that appears to be preventable.
- Well that's very true.
It's one of the few natural hazards, natural disasters,
that we know how to prevent.
If we detect em far enough out into the future,
and so that is the objective of our program here at NASA,
is find em early, as we say.
- Alright, so one more question for Kelly.
If there were some key messages
that you would want out there to tell the public,
what would those key messages be, regarding asteroids?
- Well like we've been hearing over and over again
throughout the program, is that you want to find them,
find them early, find them first.
Then you can determine what the response might be,
but if you don't know they're there,
you're not going to know what to do about them.
However, at the same time, as I always tell people,
it's not something that we're lying awake at night
worrying about, I mean we're doing what we can
and there's more that needs to be done,
but when you put it in context,
we're hard at work here at NASA
and our colleagues all through the US and through the world,
they're working hard on the problem
but again, people shouldn't be worried and fearful
if we're working on it.
- And that's what I seem to be hearing.
It's possible to take a proactive stance in all of this,
that we do know that asteroids are out there,
we do know that they could pose a real hazard,
but what I'm hearing here is this is sort of
a proactive approach that if they're out there,
let's find them and then let's see what we're dealing with.
- Yes, Gay.
Because we have a space program,
we have the technologies to go out and be able to
move these small bodies in space now.
This is something that we can prevent.
We just need to have the
will to put the programs together,
to first of all find them well before the impacts,
and then have the capabilities demonstrated
that would be able to divert the objects.
- Thank you so much.
This was a very, very informative program,
and thank you so much for your information.
Here are the websites once again,
the Planetary Defense website,
the Minor Planet Center website,
and CNEOS.
Thank you so much for joining us,
I hope you learned something,
and we hope your questions were answered.
-------------------------------------------
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