Evidence for the Big Bang — Reading Comprehension

Have you ever wondered how the universe began? Scientists have a leading idea called the Big Bang theory. This theory suggests that our universe started from a very hot, dense point and has been expanding ever since. Think of it like a balloon being inflated – as the balloon gets bigger, the dots drawn on its surface move further apart. This expansion is happening to the entire universe, not just a small part.

One of the strongest pieces of evidence for the Big Bang is the expanding universe. Scientists observe that almost all galaxies are moving away from us, and the ones furthest away are moving the fastest. This is similar to how the dots on the inflating balloon spread out. When light from distant galaxies reaches us, it appears stretched, shifting towards the red end of the spectrum. This is called redshift. Redshift tells us that objects are moving away from us, and a greater redshift means they are moving faster and are further away.

Another crucial piece of evidence is the cosmic microwave background radiation (CMBR). Imagine the entire universe being incredibly hot and bright when it was very young. As it expanded, it cooled down. The light from that early, hot universe would have stretched out as the universe grew. Today, we can detect this ancient light as faint microwaves coming from every direction in space. It's like an echo of the Big Bang, a leftover glow from when the universe was just a baby. Scientists like Arno Penzias and Robert Wilson accidentally discovered this radiation in 1964, and it was a huge discovery for the Big Bang theory.

The Big Bang theory also explains the abundance of light elements like hydrogen and helium in the universe. During the universe's earliest moments, it was hot enough for these elements to form. The amounts we observe today match the predictions of the Big Bang model. So, the expanding universe, the CMBR, and the presence of these light elements all provide strong clues that the Big Bang theory is a good explanation for how our universe began and continues to evolve. Scientists use powerful telescopes to gather this fascinating data.

Interesting Fact: The cosmic microwave background radiation is so uniform that it's often called the 'most perfect black body ever observed', meaning it's almost perfectly smooth in temperature across the sky.

What is the leading idea about the universe's beginning?

What is CMBR an echo of?

What happens to light from distant galaxies?

What does redshift tell scientists about objects?

What did the universe do as it expanded?

Which elements did the Big Bang explain?

How is the expanding universe like a balloon?

What did Penzias and Wilson accidentally discover?

The Big Bang theory states the universe is shrinking.

What does 'redshift' mean in the passage?