The Life and Death of a Star

15 Points Per Correct Answer - No time limit  

1. Most stars tend to form in large clouds of gases in space. What are these clouds called? Nebulae Quazars Galaxies Accretion disks

2. Which element contained in nebular clouds acts as the fuel for newly-formed stars? Helium Hydrogen Oxygen Petrolium

3. When gases and dust in nebulae start gathering together due to gravity, they form into large clumps. What are these clumps of gas and dust known as? Nebules Globular clusters Bok globules Star-process clusters

4. When the gas/dust compression due to gravity is balanced by the pressure created inside the forming star, what state is said to have been achieved? Nuclear equilibrium Graviostatic balance Hydrostatic equilibrium Core-Pressure balance

5. Once a star has gathered enough mass and achieved hydrostatic equilibrium, the pressure (and resultant increased temperature) ignites nuclear fusion in the star's core. It will spend approximately the next 90% of its life fusing hydrogen into helium. What is this stage of the star's life called? Major sequence Prime sequence Main sequence Hydrogen sequence

6. Once the hydrogen in the star's core is used up, the star begins to change dramatically. What change first takes place after the main sequence? The star starts shrinking The star starts expanding The star starts breaking apart The star explodes

7. Once the hydrogen is all used up, a star will begin fusing the helium instead. Heavier stars will be able to fuse progressively heavier elements together, if their masses can support it. One element, however marks the end of regular fusion in a star's core, as it cannot be fused any further. Which element is this? Carbon Iron Zinc Sulphur

8. If the mass of the star's core exceeds a critical mass point (called the "Chandrasekhar Limit"), the star experiences a catastrophic explosion called a supernova. What happens in the core of a supernova? All activity stops Nuclear fission begins Neutrons are formed The star restarts its life cycle

9. Once neutron stars exceed a certain critical mass, even the neutrons are compressed to such a state that their composition particles are forced together. The core is packed together so tightly, that a "singularity" is believed to have been formed. This creates what is known as a black hole. What are the particles that make up a neutron called? Neutrinos Photons Bosons Quarks

10. While a black hole signifies the ultimate end to a star's life cycle, it is not the only way for a star to end its life. Which of the following is not a final stage of a star? White dwarf Protostar Brown dwarf Neutron star