Name: Black Hole Hunter: Andrea Ghez
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Andrea Ghez asks the ultimate question: Is there a supermassive black hole at the center of our galaxy?

Andrea Ghez asks: Is there a supermassive black hole at the center of our galaxy?

Black Hole Hunter: Andrea Ghez

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<div class="rich-text">Andrea Ghez asks the ultimate question: Is there a supermassive black hole at the center of our galaxy?
</div>

<div class="rich-text">Andrea Ghez asks the ultimate question: Is there a supermassive black hole at the center of our galaxy?</div>

Space & Flight

<div class="rich-text"><h3>
 Black Hole Hunter: Andrea Ghez
</h3>

 Published January 10, 2018



 Andrea Ghez
 
 : The art of being a good scientist, is actually having good taste in questions. Questions that are answerable and interesting.


 I’m Andrea Ghez. G-H-E-Z



 Onscreen
 
 : ANDREA IS ON A QUEST FOR



 Ghez
 
 : Black holes…super massive black holes.


 They're the most exotic objects in the universe. As a child, they used to keep me up at night. What does it mean that something has no finite size? No edge? No beginning? No end?



 Onscreen
 
 : WHY DID YOU BECOME A SCIENTIST?



 Ghez
 
 : I think my first fascination with science and astronomy and astrophysics came from the moon landing. I was four when that happened. So now you can figure out how old I am. And I was totally fascinated. Got me hooked.


 There’s maybe the confession that, not only did I want to be an astronaut, but I also wanted to be a ballerina. It wasn't, it wasn't obvious to me that I would become a scientist



 Onscreen
 
 : WHERE DO BLACK HOLES COME FROM?



 Ghez
 
 : So, stars have a life cycle. They’re born, they live, And then the most massive stars, end up as black holes. They are defined by their gravity. Immense, immense amounts of gravity. Gravity so intense that nothing can escape them, not even light.



 Onscreen
 
 : MORE THAN 20 YEARS AGO ANDREA POSED AN INTERESTING QUESTION:



 Ghez
 
 : Is there a super massive black hole at the center of the galaxy?



 Onscreen
 
 : HOW COULD YOU FIGURE THAT OUT?



 Ghez
 
 : Matter as it gets close to the black hole, due to the very intense gravity starts to move at very high speeds. So, to prove that there’s a super-massive black hole at the center of the galaxy, we’re going to watch the orbit of stars. Stars that are as close to the center of the galaxy as possible. Which means that I want the largest telescope I can possibly get my hands on.



 Onscreen
 
 : ANDREA GOT HER HANDS ON THE KECK TELESCOPE IN HAWAII



 Ghez
 
 : Not a bad place to have to go to work. It's the largest telescope in the world. Which means I can see closer to the center of the galaxy. In theory!



 Onscreen
 
 : PROBLEM?



 Ghez
 
 : The problem for the Keck telescope is that it's here on Earth and we have to see through our atmosphere. A total headache for astronomers. Stars look like big blobs. The Earth's atmosphere is like a circus fun house mirror. So, if you look at yourself in a circus fun house mirror you look completely distorted. And then we introduce a second mirror that's the exact opposite shape to correct for the effects of the Earth's atmosphere.



 Onscreen
 
 : AND IT WORKED



 Ghez
 
 : These are factor of twenty sharper than if you had done nothing. And for the first time, we can see the center of the galaxy and in particular these stars. They're the ones that are going to tell us what's at the center of the galaxy.


 So, we started off in 1995. And every year since then we've taken an image. Just take a picture. And you watch how things move on the plane of the sky.



 Onscreen
 
 : THE PICTURES REVEAL THE STARS’ ORBITS AROUND AN UNSEEN OBJECT THAT IS MAKING THEM GO VERY FAST!



 Ghez
 
 : Up to 10 million miles per hour. They’re really hauling.



 Onscreen
 
 : KNOWING THE STARS’ SPEEDS, ANDREA CAN ESTIMATE THE MASS OF THE INVISIBLE OBJECT



 Ghez
 
 : Four-million times the mass of the Sun. This is the proof that there’s a super massive black hole at the center of our galaxy, and that super massive black holes exist.



 Onscreen
 
 : AN OVERWHELMING BODY OF EVIDENCE



 Ghez
 
 : I think…I think we have people convinced.

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