Alright, we now know we can
save Earth from an asteroid.
On September 26, NASA and the rocket
scientists from Johns Hopkins
Applied Physics Lab successfully
crashed a satellite into an asteroid.
We were told it was like running
a vending machine into a football
stadium at 14,000 miles an hour.
Not just for fun. No, no.
They wanted to know if it was possible to
knock an asteroid off its path toward Earth,
should that need ever come up.
They called it dart.
They still call it dart,
the double asteroid redirection test.
And, well, they passed that.
Best finding out today that crash into that
asteroid had a bigger impact than expected.
The head on crash slowed down its orbit by
32 minutes and was such a successful test.
They knew the outcome weeks
before they expected to.
So we thought we'd check back
in with Doctor Harrison agrusa,
the Eagle High Grad who now has
to figure out what happens next.
For fans of astronomy and pretty
much all things celestial.
The crash that happened 2 weeks ago
had a much bigger impact on science.
Yeah, so this is the first time humanity has
measurably altered the orbit of a
celestial body. Just super exciting.
That's pretty cool thing to
put on your resume. Yeah, Eagle
High grad degree in physics and astrophysics
from Berkeley, doctorate from Maryland.
Harrison Agrusa already had quite the resume.
And now you can add interplanetary defender,
where there are a lot of party
hats, confetti, high fives.
What was the reaction?
Yeah. Well, the first thing is once
we detected the new orbit period,
that also meant that we detected that
Dimorphous was still there, right?
So that was that was where we clapped.
They're like, oh,
thank God we didn't destroy the thing.
Which, you know, it would be
cool I guess if it was destroyed.
I didn't make headlines
and and stuff like that.
But it would be bad for a
planetary defense test, right?
Because if we can't measure
the results of the test,
then it's useless, right?
And if we're going to *******
asteroid in in real life,
we don't want to blow the thing to
bits because now we just turned 1
projectile into a shotgun basically,
right?
Yeah,
it's good you didn't destroy it.
But that would have made a pretty cool movie.
Yeah, it would have been, would have been
a cool movie. But yeah, NASA would have
been upset with us because we would have,
it would have been an untestable thing.
The test was to see how much they could
change the trajectory of an asteroid.
The basic goal was to slow
its orbit by about a minute,
but we expected a little bit more than that.
So between 10 minutes
and and maybe 50 minutes,
most people probably thought it'd
be more like 10 to 20 minutes.
So right, the 30 minute change
wasn't outside of the rewind.
Possibilities, but you know a lot
of us were I guess pleasantly
surprised as how I would put
it now is when Harrison's work
takes off to figure out the new
orbital dynamics of dimorphous.
So now you know the pre impact orbit
was this sort of circular thing and now
it's shrunk by 32 minutes of the orbits,
gotten a little smaller.
So now Dimorphous is orbiting slightly
closer to didymos than it was before.
So the gravity it's feeling from
didymos is a little bit stronger.
That orbit is slightly eccentric.
So it's no longer this nice circle,
it's maybe more of an ellipse.
And So what we think might happen
in this is part of my job is
dimorphous will start wobbling in
its orbit as it's orbiting around.
Will that wobble affect future
missions to that area of space? Well,
that's where Harrison's PhD comes in. Sort
of what kind of math have you
been doing to figure this all out?
You know, actually a lot of it is
high school physics, to be honest.
I do. I use a lot of basic
physics in college physics.
Still, you know, simple conservation.
Momentum and energy, right?
If anyone's listening,
if you're in high school,
I use that stuff every day.
And The funny thing is,
I still have to Google it every day.
I forget all the time all those
equations that your teachers say
you need to have this memorized.
I don't memorize any of it. I'm.
I'm Googling that stuff every other day.
But the concepts I remember, right,
it's just the exact formula I forget.
Still know the Pythagorean theorem,
by the way he calls himself a PhD
Harrison says his job will be to figure
out why that asteroid slowed down.
That orbit did more than expected.
Maybe it was heavier than they thought.
He also has to figure out the new orbit
and its wobble that he talked about,
since in four years there will be a
mission to that space of space which
will help get a clearer picture of
what that crash did to that asteroid.
So his work will help them not
be another unintended crash.