Astronomy 103: The Evolving Universe

These flashcards cover fundamental concepts and key information from the lecture notes on telescopes, their functions, star classification, stellar evolution, and astronomical observations to prepare for the upcoming exam.

Who was known for using the telescope around 1610?

Galileo.

What was one major advancement of Herschel's Telescope built in 1789?

It was a 40-foot telescope that improved telescope technology.

What is the primary function of telescopes?

To collect light and direct it towards a focus point.

What is the difference between refractors and reflectors?

Refractors use lenses to focus light, while reflectors use mirrors.

What makes a telescope 'better'?

Its light-collecting ability and image sharpness.

What type of telescopes are constructed using polished glass coated with silver or aluminum?

Reflectors.

What is the significance of the WIYN telescope constructed in 1994?

It serves as a modern example of telescope technology.

What is angular resolution?

The ability to differentiate two close objects in the sky.

If the diameter of a telescope is doubled, how much more light can it collect?

Four times as much light.

What limits the resolution of telescopes?

Diffraction.

Which telescope is known for its resolution of approximately 0.052 arcseconds?

Hubble Space Telescope.

What role does atmospheric seeing play in observing stars?

It affects star visibility due to light refraction and turbulence.

What does CCD stand for in telescope technology?

Charge-Coupled Devices.

What is the largest radio telescope in the world?

FAST Radio Telescope in Guizhou, China.

What did the Hubble Space Telescope launch in 1990 achieve?

Contributed significantly to our understanding of the universe.

What are the two main types of telescopes?

Ground-based and space-based telescopes.

What is the relationship between brightness and distance according to the Inverse Square Law?

Brightness decreases with the square of the distance.

What determines a star's surface temperature?

Wien’s Law.

What is parallax in astronomy?

The apparent shift of a nearby star against distant stars as observed from different positions of Earth.

What affects the luminosity of a star?

Its total energy emission per second.

What is a parsec?

A unit of distance equal to 206,265 AU.

How are distances to stars calculated using parallax?

Using the formula relating parallax angle to distance.

What did Newton explain in relation to planetary motion?

Fundamental laws of motion and gravity.

What is Kepler's First Law of Planetary Motion?

The orbits of planets are ellipses with the Sun at one focus.

What does conservation of linear momentum state?

The total momentum remains constant unless acted upon by an external force.

What is the main difference between brightness and luminosity?

Brightness varies with distance, while luminosity is the total energy emitted.

What determines the spectral classification of a star?

Its temperature.

What happens in a stellar binary system?

Two stars orbit around a common center of mass.

What is a white dwarf?

The remnant core of a low-mass star that has shed its outer layers.

What is the significance of a star's mass in its evolution?

Mass determines structure, fusion rates, and lifespan.

What phenomenon occurs when a white dwarf exceeds 1.4 solar masses?

It can lead to a white dwarf supernova.

What is electron degeneracy pressure?

A quantum mechanical effect preventing gravitational collapse in white dwarfs.

Why do supernovae play a crucial role in stellar recycling?

They distribute heavy elements into the interstellar medium.

How is the main sequence lifetime of a star determined?

By the amount of fuel available and the rate of fuel consumption.

What occurs when a star runs out of hydrogen in its core?

It begins to fuse helium and evolves into a red giant.

What is the role of molecular clouds in star formation?

They provide the environment for star formation by collapsing under gravity.

At what temperature does hydrogen fusion typically begin in a star?

Around 1 million K.

What distinguishes a protostar from a main sequence star?

A protostar has not yet initiated hydrogen fusion.

What is the initial composition of the Sun comprised of?

Approximately 70% hydrogen and 30% helium.

What happens to the outer layers of a red giant star?

They are ejected to form a planetary nebula.

What defines the lifecycle of a massive star after it has become a red giant?

It fuses heavier elements and eventually may undergo a supernova.

How are neutron stars formed?

From the remnants of massively exploded stars, undergoing core collapse.

What is a pulsar?

A rapidly rotating neutron star emitting beams of radiation.

The fusion of what element typically ceases to produce energy in a dying star?

Iron.

What is the mass range in which stars are classified?

Stars range from 0.1 to 100 times the mass of the Sun.

How long does it take the Sun to convert hydrogen into helium?

Approximately 10 billion years.

What is the main outcome of hydrogen fusion in terms of stellar evolution?

It sustains stars on the main sequence for most of their lives.

What effect does mass have on a star's evolution path?

More massive stars evolve and fuse elements more quickly than low-mass stars.

What is the role of gravity in the formation of stars within molecular clouds?

Gravity overcomes pressure, leading to collapse and star formation.

What occurs in the outer layers of red giants during their final stages?

They are expelled, creating observable nebulae.