Gabriela González: How LIGO discovered gravitational waves (with English subtitles) | TED

TL;DR

This content explains the discovery of gravitational waves, their significance in understanding the universe, and the possibilities they hold for exploration.

Transcript

A little over 100 years ago, in 1915, Einstein published his theory of general relativity, which is sort of a strange name, but it's a theory that explains gravity. It states that mass -- all matter, the planets -- attracts mass, not because of an instantaneous force, as Newton claimed, but because all matter -- all of us, all the planets -- wrinkl... Read More

Key Insights

• 🌌 Einstein's theory of general relativity explains gravity as the curvature of space-time caused by the presence of matter, challenging Newton's laws of motion.

Questions & Answers

Q: What is the theory of general relativity proposed by Einstein in 1915?

The theory of general relativity, proposed by Einstein in 1915, explains gravity by stating that mass, including all matter and planets, attracts other mass. This attraction occurs because all matter and planets cause the flexible fabric of space-time to wrinkle. It is in space-time that we live and that connects us all.

Q: How did Einstein derive the existence of gravitational waves from his theory of general relativity?

In 1916, Einstein derived from his theory of general relativity that gravitational waves exist. According to his theory, these waves are produced when masses, such as two stars revolving around each other, create folds in space-time. These waves carry energy from the system, causing the stars to move towards each other.

Q: How did scientists measure the effects of gravitational waves?

Scientists measure the effects of gravitational waves by looking for changes in distances. When gravitational waves pass by Earth, they cause all distances to change, including the distances between individuals and objects. These changes are very small but are proportional to the distance. Scientists used lasers to precisely measure distances between mirrors kilometers apart in order to detect the effects of gravitational waves.

Q: When and how were gravitational waves first detected?

On September 14, 2015, gravitational waves were detected for the first time. The detectors, which are extremely sensitive interferometers, measured a signal in the form of cycles that increased in amplitude and frequency, and then decreased. The detection was confirmed in both detectors, which allowed scientists to conclude that the waves originated from two black holes merging into one more than a billion years ago.

Q: Can gravitational waves be used for practical purposes or technological advancements?

Gravitational waves may have future technological applications, but it will likely take a lot of time to derive specific technologies from them. Currently, the focus of studying gravitational waves is driven by human curiosity and the pleasure of understanding the universe. While all technology is derived from scientific discoveries, the primary goal of science is the enjoyment and exploration of knowledge.

Q: What lies ahead in the study of gravitational waves?

The detection of gravitational waves is just the beginning of a revolutionary era in astronomy. As the detectors become more sensitive, scientists expect to observe more black holes, catalog their characteristics, and explore other objects such as neutron stars turning into black holes. This new sense of "hearing" in addition to "seeing" opens up a whole spectrum of new sources to study, ultimately building a highway to further explore the universe.

Summary & Key Takeaways

• Einstein's theory of general relativity explains gravity by stating that mass attracts mass because it wrinkles the fabric of space-time, rather than through instantaneous force as Newton believed.

• In 1916, Einstein derived the existence of gravitational waves from his theory but thought they would be too minute to measure.

• In 2015, gravitational waves were detected for the first time through the work of scientists using interferometers, marking a significant breakthrough in understanding the universe.