Exploring the Missing Baryons in the Universe

The video explores the missing baryon problem, explaining that while baryonic matter should make up 5% of the universe, only 2.5% was initially detected. The video delves into the formation of elements post-Big Bang and the methods used to locate missing baryons, including the use of quasars and the Lyman-alpha forest. It discusses the warm-hot intergalactic medium (WHIM) and the challenges in detecting it. The discovery of fast radio bursts has allowed scientists to estimate the total baryonic matter, confirming the presence of missing baryons. The video concludes with a sponsor message from KiwiCo.

What percentage of the universe is expected to be made up of baryonic matter?

• 27%

• 2.5%

• 68%

• 5%

Why is the ratio of deuterium to hydrogen to helium important?

• It provides insight into the early universe's element abundances.

• It helps explain the density of dark matter.

• It determines the color of stars.

• It affects the gravitational pull of galaxies.

What is the significance of the Cosmic Microwave Background Radiation?

• It is the main component of dark energy.

• It is the source of all baryonic matter.

• It is responsible for the formation of stars.

• It provides a snapshot of the universe 400,000 years after the Big Bang.

What is the Lyman-alpha forest?

• A type of nebula found in the Milky Way.

• A collection of galaxies in the early universe.

• A cluster of black holes.

• A series of absorption lines in quasar spectra.

What role do quasars play in the search for baryonic matter?

• They are the primary source of cosmic rays.

• They create new baryonic matter.

• They act as a backlight to detect neutral hydrogen.

• They are the main source of dark energy.

What is the warm-hot intergalactic medium (WHIM)?

• A type of dark matter.

• Ionized particles between galaxies.

• A cluster of stars.

• A type of black hole.

What challenge is associated with detecting the WHIM?

• It is hidden behind dark matter.

• It is too cold to emit detectable radiation.

• It is located within black holes.

• It only emits in high energy UV or low energy X-rays.

How do fast radio bursts help in finding missing baryons?

• They create new baryonic matter.

• They allow measurement of ionized baryons through dispersion.

• They provide a backlight for quasars.

• They illuminate dark matter.

What is a fast radio burst?

• A form of dark energy.

• A long-duration pulse of radio waves.

• A short-duration pulse of intense radio waves.

• A type of quasar.

What was the outcome of using fast radio bursts to measure baryonic matter?

• They found no baryonic matter.

• They discovered new types of dark matter.

• They confirmed the presence of 5% baryonic matter.

• They disproved the existence of the WHIM.