How were stars formed?

In what form do both low-mass and high-mass stars begin and end their life cycles?

• Blackhole

• White dwarf

• Nebulae

• Red giant

Answer explanation

Yup! Nebulae are gas clouds where stars can form when temperatures rise and also what is left over after stars "die".

What do we call the period in a star’s life when it is fusing hydrogen into helium?

• Middle Ages

• Stellar Nebula

• Main Sequence

• White Dwarf

Answer explanation

That’s right. It’s the main sequence because stars spend the main part of their “life” fusing hydrogen into helium.

Which of the four fundamental forces pulled together hot, dense areas of matter in the early Universe to jumpstart the process of star formation?

• Strong nuclear force

• Electromagnetism

• Gravity

• Weak nuclear force

Answer explanation

Gravity creates a type of positive feedback loop where gravity pulls matter together, making it denser and therefore making the force of gravity just that much stronger.

When protons fuse during the formation of stars, which of the following is released in massive quantities?

• Matter

• Gravity

• Energy

• Electromagnetism

Answer explanation

The violent collisions that occur between protons in the core of stars convert their mass into HUGE amounts of energy.

Why is the formation of stars an important threshold in Big History?

• Stars created the “hot spots” necessary for further complexity.

• Stars created cosmic microwave background radiation (CMBR).

• Stars exploded during the Big Bang.

• Stars rid the Universe of dark matter.

Answer explanation

These are thresholds of increasing complexity, so it makes sense that star formation is included due to its role in creating more complexity in our Universe.

What has been an important tool in discovering what existed before the formation of stars and how stars themselves formed?

• Dark matter

• Cosmic background radiation (or cosmic microwave background radiation)

• Dark energy

• Gravity

Answer explanation

Yup! From studying the release of cosmic background radiation, we know matter was pretty evenly distributed in the Universe before stars emerged, and there were also small areas of higher temperatures where the first stars were born.

Why is the increasing temperature of matter an important step in the lighting up of stars?

• It allows subatomic particles to come together to form atoms.

• It allows for reactions that release incredible amounts of energy.

• It allows fro hydrogen to be converted to uranium

• It allows the star to eject its outer layers of heavy elements

Answer explanation

Once it passes 3000 degrees Celsius, protons break away from electrons. At 10 million degrees Celsius, protons overcome their repulsive nature and bond together with strong nuclear force that leads to a release of energy that lights up a star.

Stars themselves contain structure, but they also allow for larger forms of structure. What do we call the structure(s) formed by the gathering together of stars by gravity?

• The Universe

• Nebulae

• Solar Systems

• Galaxies

Answer explanation

Our Milky Way is one of these galaxies and contains over a 100 billion stars.

The early Universe was quite uniform. What then were the Goldilocks Conditions for the formation of stars?

• The existence of gravity

• Tiny variations in the density of matter

• Large variations in temperature

• A concentration of heavy metals

Answer explanation

These tiny variations, when coupled with the force of gravity, lead to an accumulation of matter that serves as a positive feedback loop.

Which of the following best describes the state of the Universe before the formation of stars?

• Complex but disorganized

• Tiny and simple

• Simple and uniform

• Uniform in mass but not temperature

Answer explanation

That’s right. It was a collection of mass and energy that was spread out quite evenly over its entirety. Only simple elements, like hydrogen and helium, existed.