Steady State Theory

Summary

This video explores the steady-state theory, an alternative to the widely accepted big bang theory, which posits an unchanging, infinitely old universe. Developed by Hoyle, Bondi, and Gold in 1948, it suggests continuous creation of matter to maintain a constant density despite expansion. However, evidence from radio sources, quasars, and the cosmic microwave background radiation contradicts this theory, leading to its decline in favor of the big bang model, which describes a universe that began hot and dense 13.7 billion years ago and has been expanding and cooling since.

Takeaways

• 🌌 The Steady State Theory was an alternative to the Big Bang Theory, proposing an infinite, unchanging universe without a beginning or end.
• 🔍 The Big Bang Theory, first proposed by Georges Lemaître in 1931, suggests the universe began from an explosion of a 'primeval atom' and has been expanding since.
• 📊 The Big Bang Theory aligns with observations and has been refined over 90 years to explain the universe's origin and current state.
• 📖 The Perfect Cosmological Principle central to the Steady State Theory posits the universe is the same in all directions at all times, with no evolution or change.
• 🌟 The Steady State Theory predicted continuous creation of new stars and galaxies to maintain a constant density, even as the universe expands.
• 🌌 Hubble's Law, discovered in the late 1920s, indicates that galaxies move away from us, with speed proportional to their distance, supporting the expanding universe concept.
• 📈 The universe's expansion was visualized in an animation, showing galaxies moving apart and decreasing in density over time according to the Big Bang Theory.
• 💥 The Steady State Theory was challenged by observations of more radio sources and quasars in the early universe, indicating change over time.
• 🌡️ The discovery of the cosmic microwave background radiation in 1965 provided strong evidence against the Steady State Theory, as it is a relic from the early, hot universe.
• 🔨 The Steady State Theory was ultimately discredited by evidence of an evolving universe and the inability to explain the cosmic microwave background radiation.
• 👤 Stephen Hawking acknowledged the Steady State Theory as a good scientific theory due to its testable predictions, despite being falsified.

Q & A

What is the Steady State Theory?

The Steady State Theory is an alternative to the Big Bang Theory, suggesting that the universe is infinite in extent, infinitely old, and remains the same in all directions at all times. It was developed in 1948 by Fred Hoyle, Hermann Bondi, and Thomas Gold.

What is the central principle of the Steady State Theory?

The central principle of the Steady State Theory is the Perfect Cosmological Principle, which states that the universe does not evolve or change over time.

How does the Steady State Theory explain the universe's expansion?

In the Steady State Theory, the universe's expansion is balanced by the continuous creation of new matter, maintaining a constant overall density.

What is the significance of the Big Bang Theory's development over the years?

The Big Bang Theory has been refined over the years to match observations, stating that the universe originated from an incredibly hot and dense state 13.7 billion years ago and has been expanding and cooling ever since.

What evidence supports the Big Bang Theory over the Steady State Theory?

Evidence such as the discovery of the cosmic microwave background radiation, the observation of more radio sources at greater distances, and the presence of quasars in the early universe support the Big Bang Theory, indicating that the universe has changed over time.

What is Hubble's Law and how does it relate to the universe's expansion?

Hubble's Law states that the further away a galaxy is from us, the faster it appears to be moving away. This relationship, discovered in the late 1920s, supports the idea that the universe is expanding.

What is the cosmic microwave background radiation and why is it significant?

The cosmic microwave background radiation is a weak radiation that fills all of space and has a uniform temperature of 2.7 degrees above absolute zero. It is significant because it is a relic from the early universe, supporting the Big Bang Theory.

How does the Steady State Theory explain the creation of new stars and galaxies?

The Steady State Theory suggests that new matter is continuously created out of nothing at a very small rate, eventually forming new stars and galaxies, maintaining a constant density over large regions of space.

What is the role of the Hubble constant in understanding the universe's expansion?

The Hubble constant, denoted as H naught, represents the rate of expansion of the universe. It is crucial in determining the relationship between a galaxy's distance from Earth and its speed of recession.

Why did the Steady State Theory become obsolete despite its elegance?

The Steady State Theory became obsolete due to observational evidence that contradicted its predictions, such as the discovery of the cosmic microwave background radiation and the changing number of radio sources and quasars over time.

What did Stephen Hawking say about the Steady State Theory?

Stephen Hawking noted that the Steady State Theory was a good scientific theory in the sense that it made definite predictions that could be tested and potentially falsified, which they ultimately were.