Fritz Zwicky facts for kids

Fritz Zwicky (born February 14, 1898 – died February 8, 1974) was a Swiss astronomer. He spent most of his life working at the California Institute of Technology (Caltech) in the United States. There, he made many important discoveries in how we observe and understand the universe. In 1933, Zwicky was the first to suggest that something invisible, which he called "dunkle (kalt) Materie" (dark matter), must exist in space.

Discovering Fritz Zwicky

Early Life and Education

Fritz Zwicky was born in Varna, Bulgaria. His father was Swiss, and his mother was Czech. His father, Fridolin, was a well-known businessman in Varna and even served as Norway's ambassador there. Fritz's mother, Franziska Vrček, was from the Austro-Hungarian Empire. Fritz was the oldest of three children.

When he was six, Fritz was sent to Switzerland to live with his grandparents. He was supposed to study business, but he became much more interested in math and physics. He went on to study these subjects at the Swiss Federal Polytechnic in Zurich.

Moving to America and Caltech

In 1925, Zwicky moved to the United States. He joined the California Institute of Technology (Caltech) to work with Robert Andrews Millikan. He even had an office near J. Robert Oppenheimer.

Zwicky became a Professor of Astronomy at Caltech in 1942. He also worked as a research director for Aerojet Engineering Corporation. He spent much of his career at the Mount Wilson Observatory and Palomar Observatory. He helped develop some of the first jet engines and held over 50 patents, many related to jet propulsion. He even invented an "Underwater Jet."

Family Life

In 1932, Fritz Zwicky married Dorothy Vernon Gates. Her family's money helped fund the Palomar Observatory during the Great Depression. Fritz and Dorothy divorced in 1941.

In 1947, Zwicky married Anna Margaritha Zürcher in Switzerland. They had three daughters: Margrit, Franziska, and Barbarina. Many of his papers and scientific works are kept at the Zwicky Museum in Glarus, Switzerland. Fritz Zwicky passed away in Pasadena, California on February 8, 1974, and was buried in Switzerland.

People remember Zwicky as both a brilliant scientist and someone who could be quite difficult.

Zwicky's Lasting Impact

The Fritz Zwicky Stiftung (Foundation) was created in Switzerland to continue his ideas. This foundation published a book about his life called Fritz Zwicky – An Extraordinary Astrophysicist.

Amazing Scientific Discoveries

The memorial plaque on the house in Varna where Zwicky was born. It mentions his work on neutron stars and dark matter.

Fritz Zwicky was a very busy scientist who made many important contributions to astronomy.

Supernovae and Neutron Stars

In 1934, Zwicky and his colleague Walter Baade came up with the word "supernova". They suggested that supernovae are what happens when normal stars turn into incredibly dense objects called neutron stars. They also thought that supernovae were the source of cosmic rays, which are high-energy particles from space. This idea helped scientists figure out the size and age of the universe.

To prove his idea, Zwicky started searching for supernovae. He found 120 of them himself over 52 years! This was a record until 2009. Zwicky did this hard work by comparing old photos of the sky with his own eyes, which was much harder than using today's technology.

Gravitational Lenses

In 1937, Zwicky suggested that huge groups of stars, called galaxies, could act like giant lenses in space. This idea was based on Albert Einstein's theory of gravity. It wasn't until 1979 that scientists actually saw this effect, with a distant object called the ""Twin Quasar" Q0957+561."

The Mystery of Dark Matter

While studying a group of galaxies called the Coma galaxy cluster in 1933, Zwicky noticed something strange. The galaxies were moving much faster than they should have been, based on how much visible matter was there. It was as if there was a lot more gravity than could be explained by the stars and gas we could see.

He called this missing gravitational pull dunkle (kalt) Materie, which means 'dark matter'. He figured that this invisible matter made up most of the cluster's mass. Today, we still believe that most of the matter in the universe is dark matter, even though we can't see it directly.

The "Tired Light" Idea

When Edwin Hubble discovered that distant galaxies were moving away from us (their light was "redshifted"), Zwicky had a different idea. He thought that maybe light just got "tired" and lost energy as it traveled through space, making it appear redder. He called this "tired light."

Zwicky was unsure about the idea that space itself was expanding. However, later discoveries showed that the universe is indeed expanding, and the redshift of light is a result of this expansion.

Cataloging Galaxies

From 1961 to 1968, Zwicky and his team spent a lot of time finding and listing galaxies. They published a huge six-volume book called Catalogue of galaxies and of clusters of galaxies.

Galaxies found in this original catalog are still called Zwicky galaxies. Zwicky and his wife Margaritha also created another important list of compact galaxies, sometimes called The Red Book.

A Unique Way of Thinking

Zwicky was a very original thinker. Many of his ideas were so new that other scientists weren't sure what to make of them at first. As one researcher said, "When researchers talk about neutron stars, dark matter, and gravitational lenses, they all start the same way: 'Zwicky noticed this problem in the 1930s. Back then, nobody listened...'"

He was famous for discovering neutron stars. He also had some unusual ideas, like when he told his assistant to fire a gun out of the telescope at Mount Wilson Observatory. He hoped it would help calm down the air, but it didn't work! This story shows how he thought outside the box.

Once, Zwicky told a student that rockets couldn't work in space because they needed air to push against. He later admitted he was wrong!

He was also proud of creating the first artificial meteors. He put explosives in the nose of a V2 rocket to shoot metal pellets into the atmosphere. After some tries, he succeeded in 1957, and the pellets were seen from the Palomar Observatory. It's even thought that one of these pellets might have escaped Earth's gravity and become the first object to orbit the Sun!

Zwicky even thought about moving planets or entire solar systems! He imagined moving our whole solar system like a giant spaceship to travel to other stars. He thought we could reach Alpha Centauri in about 2500 years by firing pellets into the Sun to create explosions that would push it.

A Caring Person

Zwicky was also a very kind and caring person. After World War II, he worked hard to collect tons of books on astronomy and other subjects. He then sent these books to scientific libraries in Europe and Asia that had been damaged by the war.

He also supported the Pestalozzi Foundation of America, which helped orphanages. He received a gold medal from them in 1955 for his help.

Zwicky loved mountains and was a skilled climber. He believed that good people working together, without strict organizations, could solve the world's problems.

Honors and Recognition

• In 1949, President Truman gave Zwicky the Medal of Freedom for his work on rocket engines during World War II.
• In 1968, Zwicky became a professor emeritus (a retired professor who keeps their title) at California Institute of Technology.
• In 1972, Zwicky received the Gold Medal of the Royal Astronomical Society, which is a very important award. He got it for his amazing work on neutron stars, dark matter, and cataloging galaxies.
• The asteroid 1803 Zwicky and a crater on the Moon called Zwicky are named after him.
• The Zwicky Transient Facility, a modern astronomical survey, is also named in his honor.

See also

In Spanish: Fritz Zwicky para niños