Andrea M. Ghez

Andrea is a space scientist.

She looks at the center of our galaxy. She uses big tools to see through dust. This helps her see far away stars.

She watched stars move in big circles. This showed that a huge, dark object is there. Most people call this a black hole.

Andrea won a very big prize for her work. It is called the Nobel Prize. She was the fourth woman to win it.

She is a teacher too. She likes to help others think deeply.

Andrea Ghez is a space scientist. She studies the center of our galaxy.

She uses big telescopes to see far away. One is the Keck Telescope. It is very large. She uses a tool called adaptive optics. This tool fixes blurry views from the air. It helps her see through thick space dust.

Andrea watched how stars move near the galaxy center. She saw stars move in big loops. These stars orbit, or move around, a dark object. This object is a supermassive black hole. We call it Sagittarius A*.

By watching the stars, her team found the black hole's mass. It is 4.1 million times the mass of our sun. This was a big discovery. In 2020, she won the Nobel Prize in Physics. She shared this prize with Reinhard Genzel. She was the fourth woman to win this prize. Andrea is also a teacher at UCLA. She likes to help students think deeply.

Andrea Ghez is a famous space scientist. She is an astrophysicist who studies the stars. Her work focuses on the center of the Milky Way galaxy. This part of our galaxy is very hard to see. Most of the light is blocked by thick space dust. Ghez wanted to know what was hiding in that dark area.

To see the center, she uses special tools. She uses the huge W.M. Keck Telescope. This telescope has a 10-meter aperture, which is the width of the lens. She also uses a system called adaptive optics. This system fixes the blurry views caused by the moving air in our atmosphere. By using infrared light, she can peer right through the heavy dust. This lets her see the stars near the very center.

Ghez grew up in New York City. Her father was born in Rome, Italy. Her mother came from a family in Massachusetts. When she was young, the Apollo Moon landings inspired her. She even wanted to be an astronaut! Her mother bought her a telescope to help her learn. Later, she studied physics at the Massachusetts Institute of Technology. She earned her PhD at the California Institute of Technology in 1992.

Her team watched how stars move in the center of the galaxy. They saw stars moving in big, oval paths called orbits. One star is named S2. It completed a full orbit since 1995. Another star, S0-102, was found by her team in 2012. By watching these motions, she proved a huge object was there. This object is a supermassive black hole named Sagittarius A*. It has a mass of about 4.1 million suns.

This discovery was a very big deal for science. In 2020, Ghez won the Nobel Prize in Physics. She shared this prize with Reinhard Genzel. She is only the fourth woman to ever win this prize. Before her, only Marie Curie, Maria Goeppert Mayer, and Donna Strickland won it. Today, she is a professor at UCLA. She teaches students how to use critical thinking to solve hard jobs.

Andrea Mia Ghez is a prominent American astrophysicist. Her career focuses on studying the center of the Milky Way galaxy. She is a professor at the University of California, Los Angeles. Ghez is best known for discovering a supermassive compact object at our galaxy's center. This object is widely recognized as a supermassive black hole. In 2020, she was awarded the Nobel Prize in Physics for this discovery. She shared this honor with Reinhard Genzel.

To study the center of the galaxy, Ghez uses advanced technology. The center is hidden behind heavy layers of space dust. This dust blocks visible light, making it impossible to see with normal telescopes. Ghez uses infrared wavelengths to peer through this thick dust. She utilizes the W.M. Keck Telescope, which has a 10-meter aperture. This large opening allows the telescope to collect significant amounts of light. She also employs a system called adaptive optics. This system corrects for the turbulence of the Earth's atmosphere. This technology creates high spatial resolution images that are very sharp.

Ghez's research relies on studying the kinematics of stars. Kinematics is the study of how objects move. By observing the orbits of stars, she can investigate the center of the Milky Way. Her team follows stars as they move in elliptical orbits around a central point. One specific star, named S2, has completed a full orbit since 1995. In October 2012, her team at UCLA identified another star called S0-102. These precise measurements allow scientists to calculate the mass of the central object. By using Kepler's third law, Ghez's team determined the mass of the object.

The object at the center is known as Sagittarius A*, or Sgr A*. It is a supermassive black hole. The measurements show that Sgr A* has a mass of 4.1 plus or minus 0.6 million solar masses. This means it is as heavy as about four million suns. This discovery is significant because Sgr A* is one of the best-demonstrated cases for a supermassive black hole. It is located one hundred times closer than M31*, which is the next nearest supermassive black hole. Studying Sgr A* provides a way to test the theory of general relativity.

Ghez's journey into science began with early inspirations. She was born in New York City in 1965. Her father, Gilbert Ghez, was born in Rome to a family from Tunisia and Germany. Her mother, Susanne Ghez, came from an Irish Catholic family in Massachusetts. The Apollo Moon landings inspired Ghez to become an astronaut. Her mother encouraged this interest by buying her a telescope. Ghez eventually studied mathematics before switching to physics. She earned a BS from the Massachusetts Institute of Technology in 1987. Later, she earned a PhD from the California Institute of Technology in 1992.

Throughout her career, Ghez has received many prestigious honors. In 2004, she was elected to the National Academy of Sciences. In 2012, she became a member of the American Philosophical Society. She was also elected as a Fellow of the American Physical Society in 2019. Her many awards include the MacArthur Fellowship and the Crafoord Prize in Astronomy. Ghez has also appeared in many science documentaries. These include programs on the BBC, Discovery Channel, and the PBS series Nova. She is recognized by many as a leader in her field.

Winning the Nobel Prize in Physics is a rare achievement for women. Ghez was the fourth woman to win this prize since it began. She follows the examples of Marie Curie, Maria Goeppert Mayer, and Donna Strickland. Her work connects the study of individual stars to the massive structures of entire galaxies. By understanding how stars orbit Sgr A*, scientists learn more about gravity and space. Ghez continues to teach at UCLA. In her lectures, she emphasizes the importance of critical thinking for all students.