8. Space Physics Flashcards
What is the process by which stars form?
Stars form when enough dust and gas, primarily hydrogen and helium, are pulled together by gravitational attraction in space.
What happens during the main sequence period of a star’s life cycle?
During the main sequence period, energy is released by the fusion of hydrogen nuclei to make helium nuclei in the core, and the star is stable because the forces within it are balanced.
How does the mass of a star affect its life cycle?
The more massive a star, the hotter its core and the heavier the nuclei it can create by fusion, leading to a different life cycle compared to smaller stars.
What happens when a larger star runs out of hydrogen during its life cycle?
A larger star swells to become a red supergiant, in which helium nuclei fuse to form heavier nuclei like carbon, followed by further fusion producing elements like nitrogen and oxygen. Eventually, it may explode in a supernova, forming either a neutron star or a black hole.
Describe the life cycle of a smaller star, similar to our Sun.
A smaller star expands to become a red giant, sheds out layers of gas, exposes the core as a white dwarf, and eventually cools to become a black dwarf.
What is the source of energy in stars, and what do they produce?
Fusion processes in stars are the source of energy, producing all naturally occurring elements. Elements heavier than iron are formed in a supernova explosion at the end of a massive star’s life cycle.
What is the force that keeps planets and satellites in orbit?
Gravity provides the centripetal force that keeps planets and satellites in orbit around larger celestial bodies like stars or planets.
Explain the process of nuclear fusion within stars.
In the core of a star, where temperature and density are greatest, nuclear fusion occurs. Hydrogen nuclei fuse to form helium nuclei, releasing vast amounts of energy in the process. This fusion process is responsible for the energy output of stars.
Describe the fate of a larger star at the end of its life cycle.
A larger star will swell to become a red supergiant, undergo further fusion processes to produce heavier nuclei, and eventually explode in a supernova. The core may collapse to form either a neutron star or a black hole.
What objects make up our solar system?
Our solar system consists of the Sun, eight planets (including Earth), their moons, asteroids, dwarf planets (like Pluto), and comets.
Explain the concept of gravity in relation to the solar system.
Gravity is the force that keeps planets and other celestial bodies in orbit around the Sun. It provides the centripetal force needed to maintain their orbital motion.
How does the centripetal force due to gravity change with distance in orbiting bodies?
The centripetal force due to gravity decreases as the separation between orbiting masses increases. This results in lower orbital speeds at greater distances from the center of mass.
What determines the stability of an object’s orbit around a massive body?
To stay in a stable orbit at a particular distance from a massive body, such as a planet or the Sun, the object must move at a specific speed. A change in orbital speed results in a change in orbital radius.
What is red shift, and what does it indicate about the universe?
Red shift refers to the observed increase in the wavelength of light from distant galaxies. This effect suggests that galaxies are moving away from us, indicating an expanding universe and supporting the Big Bang theory.
What is the cosmic microwave background radiation (CMBR)?
CMBR is a form of electromagnetic radiation filling the universe. It originates from radiation present shortly after the Big Bang and provides evidence for the early stages of the universe.
