Scientists made important discoveries in the early 1900s that helped us understand that our universe is always growing. Here are some key observations:
Redshift of Galaxies
In the 1920s, a scientist named Edwin Hubble made a big discovery. He looked at the light from faraway galaxies and noticed something strange. The light appeared redder than normal. This redshift meant the galaxies were moving away from us.
Hubble wrote down a rule called Hubble's Law. It shows how far away a galaxy is and how fast it is moving away. This finding suggested that the universe wasn’t still—it was expanding!
Cosmic Microwave Background Radiation (CMB)
Fast forward to 1965, when two scientists, Arno Penzias and Robert Wilson, found something unexpected. They discovered a faint glow in the sky called cosmic microwave background radiation.
This glow is like an echo from the hot, dense beginning of our universe. It helped support the Big Bang theory, which says our universe has been expanding ever since it started.
Light Elements
The Big Bang theory also predicts that certain light elements like hydrogen, helium, and lithium formed in specific amounts. Scientists have checked and found that the amounts of these elements in the universe match what was expected from the Big Bang.
This supports the idea that our universe was once in a hot, dense state and is now expanding.
Large-Scale Structure
Scientists have also looked at how galaxies are arranged in the universe. They can see that galaxies are spread out in a way that fits with the idea of an expanding universe.
For example, they noticed there are large empty areas called cosmic voids, and long strings of galaxies called filaments. This shows how galaxies have moved apart over time.
All these important observations work together to give us a better understanding of a lively and expanding universe. They change how we think about cosmology and how everything began.
Scientists made important discoveries in the early 1900s that helped us understand that our universe is always growing. Here are some key observations:
Redshift of Galaxies
In the 1920s, a scientist named Edwin Hubble made a big discovery. He looked at the light from faraway galaxies and noticed something strange. The light appeared redder than normal. This redshift meant the galaxies were moving away from us.
Hubble wrote down a rule called Hubble's Law. It shows how far away a galaxy is and how fast it is moving away. This finding suggested that the universe wasn’t still—it was expanding!
Cosmic Microwave Background Radiation (CMB)
Fast forward to 1965, when two scientists, Arno Penzias and Robert Wilson, found something unexpected. They discovered a faint glow in the sky called cosmic microwave background radiation.
This glow is like an echo from the hot, dense beginning of our universe. It helped support the Big Bang theory, which says our universe has been expanding ever since it started.
Light Elements
The Big Bang theory also predicts that certain light elements like hydrogen, helium, and lithium formed in specific amounts. Scientists have checked and found that the amounts of these elements in the universe match what was expected from the Big Bang.
This supports the idea that our universe was once in a hot, dense state and is now expanding.
Large-Scale Structure
Scientists have also looked at how galaxies are arranged in the universe. They can see that galaxies are spread out in a way that fits with the idea of an expanding universe.
For example, they noticed there are large empty areas called cosmic voids, and long strings of galaxies called filaments. This shows how galaxies have moved apart over time.
All these important observations work together to give us a better understanding of a lively and expanding universe. They change how we think about cosmology and how everything began.