Lecture 2 Flashcards
(28 cards)
What element is carried by iron-bearing haemoglobin in our blood?
Oxygen
What forms the backbone of proteins, fats, and carbohydrates in our cells?
Chains of carbon and nitrogen
What element strengthens our bones?
Calcium
Which ions moderate communications in the nervous system?
Sodium and potassium ions
What are the primary elements created by stars that are fundamental to life?
Hydrogen and helium
How are heavier elements created in the universe?
Through stellar explosions
What is the age of the Earth in millions of years?
4500 million years
What type of stars are found in young open clusters?
Massive, bright, and hot stars
What regions are young star clusters typically found in?
Regions of high nebulosity
What are the three distinct regions of the Triffid nebula?
- Emission nebula
- Reflection nebula
- Extinction or Dark nebulae
What characterizes the emission nebula in the Triffid nebula?
It is red/pink and is an HII region ionized by energetic photons
What causes the blue color in reflection nebulae?
Scattering of blue light by dust grains
What are dark nebulae also known as?
Extinction nebulae
What happens during the collapse of a large molecular cloud?
Gravity pulls gas toward the densest regions, forming new stars
What heats up a cloud fragment during star formation?
Gravitational potential energy
What is a protostar?
The dense center of a cloud fragment that will become a new star
What is the temperature of a cloud during the initial stages of star formation?
Below 100 K
What prevents the temperature and pressure from building up enough to resist gravity in a protostar?
Radiation escaping from the contracting gas
What happens when the central region of a cloud fragment becomes dense enough?
The central temperature and pressure begin to rise
What causes protostars to rotate rapidly?
Conservation of angular momentum
What distinguishes protostars from true stars?
Their cores are not hot enough for nuclear fusion
What forms around a protostar due to its rotation?
A spinning disk of gas
What do jets from young stars do?
Fire high-speed streams of gas into interstellar space
What likely plays a role in how protostars generate jets?
Magnetic fields
