2023/02/24(Fri)
11:00 -12:00
視訊演講 Video Seminar [ Meeting Link / ID: 2512 054 2782 / Password: FridaySeminar23 ]
Title
Gravitational waves as a window to the Universe
Speaker
Dr. Otto Hannuksela (The Chinese University of Hong Kong)Abstract
Gravity has had an interesting story, having been revolutionized twice in history, first by Isaac Newton and then by Albert Einstein. As the story goes, sometime in the 17th century, Isaac Newton sat under an apple tree, observing an apple fall in the distance. As the apple fell, Newton, according to the story, realized how the Moon in the sky orbits Earth because of the same force that made the apple fall, gravity. Gravity then became a force permeating the entire Universe. That is, until the 20th century, when Albert Einstein formulated his theory of gravity based on the principles of relativity. In Einstein's view, gravity was not a force but a consequence of spacetime curvature, an idea that revolutionized modern physics. Today, we understand that all accelerating objects emit "gravitational waves," otherwise known as ripples in the fabric of spacetime. These waves stretch and squeeze spacetime as they whiz past objects at the speed of light, carrying with them information about some of the most violent phenomena in the Universe. To record the sound of gravitational waves, one must observe the stretching of space at scales smaller than the smallest nucleus of an atom. To this end, LIGO, Virgo, and KAGRA collaboration have built extremely precise laser interferometric detectors. The detectors observed the first wave, from two colliding black holes, in 2015. Since then, there have been nearly 100 published detections, thanks to the continued improvement of the detectors. Indeed, the advent of the first detection started an entirely new observational era in astronomy. Detecting and analyzing the information carried by gravitational waves allows us to observe the Universe in a way never before possible, providing astronomers and other scientists with glimpses of unseeable wonders that aid in studying the cosmos. In this talk, I will discuss our recent work in the field.
Language
演講語言 (Language): in English
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