Cosmic Queries – The Big Stretch
StarTalk Radio
Deep Dive
Why do photons come from candles or stoves?
Photons are released when electrons in atoms drop from a higher energy level to a lower one. In candles or stoves, heat causes electrons to become excited and then drop back, releasing photons in the process.
Why did it take a century to detect gravitational waves after Einstein's prediction?
Einstein predicted gravitational waves in 1916, but the technology to detect them was not advanced enough until 2015. The first detection was made using LIGO, which can measure tiny distortions in space-time caused by passing gravitational waves.
Why is the universe described as a 'fabric' that can stretch and rip?
The Big Bang is not an explosion in the traditional sense but rather a rapid stretching of space-time. The term 'Big Stretch' more accurately describes the expansion of the universe from a singularity.
Why do black holes form after a star goes supernova?
Stars above a certain mass will collapse into black holes after a supernova. If the star's mass is sufficient, the gravitational pull will be so strong that it will collapse into a singularity, forming a black hole.
Why can't black holes be dark matter?
Dark matter does not interact with ordinary matter except through gravity. Black holes, made from ordinary matter, would interact in ways that would make the universe look different from what we observe. Therefore, dark matter cannot be black holes.
What are the sources of tidal energy?
Tidal energy primarily comes from the gravitational pull of the moon, with a smaller contribution from the sun. The moon's gravitational force causes tides to rise and fall, which can be harnessed for energy.
Why is osmium denser than gold despite having fewer protons?
Osmium atoms pack more closely together due to their atomic and quantum properties, making osmium the densest element, not the heaviest. This density makes osmium useful in applications requiring hardness and durability, such as fountain pen tips.
- Photons are packets of pure energy.
- Photons are created when energy is released from atoms or molecules.
- Fire creates photons by releasing energy from burning fuel sources like wax.
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