star power

particle accelerators

In particle accelerators, subatomic particles are propelled until they have attained almost the same amount of energy as found in the core of a star (Figure 1.3). When these particles collide head-on, new particles are created. This process simulates the nuclear fusion that takes place in the cores of stars. The process also simulates the conditions A diagram of a star like the Sun. that allowed for the first helium atom to be produced from the collision of two hydrogen atoms in the first few minutes of the universe. The SLAC National Accelerator Lab in California can propel particles a straight 2 mi (3.2 km). The CERN Particle Accelerator presented in this video is the worlds largest and most powerful particle accelerator. The accelerator can boost subatomic particles to energy levels that simulate conditions in the stars and in the early history of the universe before stars formed. Click image to the left or use the URL below. URL:

textbook_image

textbook_image

nuclear fusion

Stars are made mostly of hydrogen and helium, which are packed so densely in a star that in the stars center the pressure is great enough to initiate nuclear fusion reactions. In a nuclear fusion reaction, the nuclei of two atoms combine to create a new atom. Most commonly, in the core of a star, two hydrogen atoms fuse to become a helium atom. Although nuclear fusion reactions require a lot of energy to get started, once they are going they produce enormous amounts of energy (Figure 1.1). In a star, the energy from fusion reactions in the core pushes outward to balance the inward pull of gravity. This energy moves outward through the layers of the star until it finally reaches the stars outer surface. The outer layer of the star glows brightly, sending the energy out into space as electromagnetic radiation, including visible light, heat, ultraviolet light, and radio waves (Figure 1.2).

textbook_image

star power

The Sun is Earths major source of energy, yet the planet only receives a small portion of its energy. The Sun is just an ordinary star. Many stars produce much more energy than the Sun. The energy source for all stars is nuclear fusion.

instructional diagrams

No diagram descriptions associated with this lesson

questions

only a few stars are made of hydrogen and helium; most are made of heavier elements.

a) true

-->  b) false

a thermonuclear bomb

a) is an uncontrolled fission reaction.

b) is a controlled fission reaction.

-->  c) is an uncontrolled fusion reaction.

d) is a controlled fusion reaction.

which type of energy does a star emit?

a) visible light

b) ultraviolet light

c) radio waves

-->  d) all of the above

there is only one particle accelerator for scientists to use.

a) true

-->  b) false

this keeps a star from collapsing from its own gravity.

-->  a) the energy from fusion

b) centrifugal force.

c) anti-gravity.

d) none of these.

the core of a star like the sun is so hot that nuclear fusion takes place.

-->  a) true

b) false

fusion is __.

a) the splitting of one atom to create two new atoms.

-->  b) the combining of atoms to create a new atom.

c) the creation of heavy elements from light elements.

d) none of these.

the sun produces more energy than most stars.

a) true

-->  b) false

a particle accelerator

a) creates conditions in which subatomic particles split apart.

b) creates conditions in which nuclear fission happens.

-->  c) boosts subatomic particles to extremely high energy levels.

d) all of these.

scientists use particle accelerators to study conditions in

a) the cores of stars.

b) the first few minutes of the early universe.

c) which hydrogen fuses to produce helium.

-->  d) all of these.

diagram questions

No diagram questions associated with this lesson