Cosmic Queries – Galaxies Galore | Startalk Radio

Intro

In this episode of Startalk Radio, titled “Cosmic Queries – Galaxies Galore,” hosts Neil deGrasse Tyson and Kevin Semoyay discuss galaxies and how astronomers determine distances to stars and galaxies in the universe. They also explore the impact of the James Webb Space Telescope and answer questions from fans about dark matter, the expansion of the universe, and potential alien life.

Main Takeaways

Methods for Determining Distances to Stars and Galaxies

• Astronomers use various methods to determine distances to stars and galaxies, including geometric techniques and measuring the rate at which a star gets dimmer as it moves away.
• The book “Cosmic Queries” provides in-depth information on these concepts and serves as a valuable resource.
• The accuracy of methods and tools used for closer objects affects the distances to farther objects.
• The James Webb Space Telescope is expected to revolutionize our understanding of the early universe and provide groundbreaking insights.

Triangulated Distance Method and Gaia Satellite

• The triangulated distance method can be applied to stars with different luminosities, not just those similar to the Sun.
• The Gaia satellite is designed to measure the triangulated distance to a billion stars with high precision.
• Hubble used stars that pulsate to calculate their distance, leading to the birth of modern stellar astrophysics.
• The women of Harvard College Observatory played a significant role in the discovery and calculation of stars, despite being overlooked by the men.

Dark Matter and the Expansion of the Universe

• Dark matter is a mysterious form of gravity that does not interact with ordinary matter and does not have a corresponding force holding it together.
• Understanding dark matter challenges our assumptions about why things stick together in our world.
• The expanding universe is likened to galaxies embedded in the stretching fabric of space, similar to drawing on the surface of a balloon.
• There are no known theories about dark matter converting into dark energy, and there is no evidence of one converting to the other as the universe expands.

Potential Alien Life and Future Telescopes

• Aliens might be interested in life existing anywhere in the universe and could potentially have longer lifespans, allowing for interstellar travel.
• Wormholes are hypothetical portals through the fabric of space-time that would allow for instantaneous travel.
• The James Webb Space Telescope (JWST) is expected to revolutionize our understanding of the universe and provide groundbreaking insights into the cosmos.
• New telescopes, like the James Webb Space Telescope and potential 30-meter telescope, will transform our understanding of the universe.

Summary

Methods for Determining Distances to Stars and Galaxies

In order to determine distances to stars and galaxies, astronomers employ various methods. These include geometric techniques, such as using two sight lines that intersect at a single point to calculate the distance to an object. The entire orbit of the Earth can also be used as a baseline to measure the distance to faraway objects like stars. Additionally, scientists can measure the angle between stars and calculate the distance by taking pictures of stars against the background stars and waiting six months to take the same picture again. The accuracy of methods and tools used for closer objects affects the distances to farther objects. The James Webb Space Telescope is expected to provide significant advancements in our understanding of the early universe and contribute to our knowledge of distance measurements.

Triangulated Distance Method and Gaia Satellite

The triangulated distance method allows astronomers to calculate distances to stars with different luminosities, not just those similar to the Sun. This method involves using the Gaia satellite, which is designed to measure the triangulated distance to a billion stars with high precision. The work of astronomers like Hubble, who used stars that pulsate to calculate their distance, has led to significant advancements in stellar astrophysics. It is worth noting that the women of Harvard College Observatory played a crucial role in the discovery and calculation of stars, despite being overlooked by their male counterparts.

Dark Matter and the Expansion of the Universe

Dark matter, a mysterious form of gravity that does not interact with ordinary matter, poses challenges to our understanding of why things stick together in our world. It does not have a corresponding force holding it together, causing it to spread out over galaxy clusters. The expansion of the universe can be likened to galaxies embedded in the stretching fabric of space, similar to drawing on the surface of a balloon. There are no known theories about dark matter converting into dark energy, and there is no evidence of one converting to the other as the universe expands.

Potential Alien Life and Future Telescopes

Speculating on potential alien life, it is suggested that aliens might be interested in life existing anywhere in the universe and could potentially have longer lifespans, enabling interstellar travel. Wormholes, hypothetical portals through the fabric of space-time, could allow for instantaneous travel. The James Webb Space Telescope (JWST) is expected to revolutionize our understanding of the universe and provide groundbreaking insights into the cosmos. Furthermore, the development of new telescopes, such as the potential 30-meter telescope, will transform our understanding of the universe by allowing us to observe previously unseen phenomena.

Conclusion

The episode “Cosmic Queries – Galaxies Galore” of Startalk Radio delves into the fascinating subject of galaxies and how astronomers determine distances to stars and galaxies in the universe. It explores various methods, including geometric techniques and measuring the rate at which stars get dimmer as they move away. The episode also touches on dark matter, the expansion of the universe, potential alien life, and the exciting advancements brought by telescopes like the James Webb Space Telescope. Overall, it encourages listeners to stay curious and embrace the questions that arise in the pursuit of scientific knowledge.