Astronomy Review (Chapter 6-10)

Telescope

An instrument that collects faint light from astronomical sources and brings it to a focus for further analysis.

Light-gathering power

The ability of a telescope to collect light, determined by the diameter of its aperture or opening.

Refracting telescope

A telescope that uses a convex lens as its primary optical element to bring light to a focus.

Reflecting telescope

A telescope that uses a concave mirror as its primary optical element to bring light to a focus.

Adaptive optics

A technique that corrects for turbulence in Earth's atmosphere in real time, improving the resolution of visible-light or infrared telescopes.

Radio telescope

A telescope that uses a radio antenna connected to a receiver to detect and study radio waves from astronomical sources.

Infrared observations

Observations made with telescopes that detect infrared radiation, which can be done from aircraft, space, or ground-based facilities.

James Webb Space Telescope

The largest-aperture telescope in space, launched in 2022, designed to observe the infrared sky.

Plate tectonics

The movement of crustal plates on Earth's surface, resulting in phenomena such as continental drift, mountain building, and volcanic activity.

Greenhouse effect

The trapping of heat by certain gases in a planet's atmosphere, such as CO2 and methane, leading to an increase in surface temperature.

Martian Atmosphere

The atmosphere of Mars, which has a surface pressure of less than 0.01 bar and is composed of 95% CO2.

Surface Water

Liquid water is not possible on the surface of Mars today, but evidence suggests extensive surface water in the past.

Subsurface Permafrost

Mars has subsurface permafrost at high latitudes, indicating the presence of frozen water beneath the surface.

Polar Caps

Seasonal polar caps on Mars are made of dry ice (carbon dioxide ice), while the northern residual cap is water ice.

Water Erosion Features

Evidence of a different climate in the past is found in water erosion features, including runoff channels and outflow channels carved by catastrophic floods.

Ancient Lakebeds

Rovers exploring Mars have discovered ancient lakebeds and sedimentary rock formations, providing evidence for extensive surface water in the past.

Flowing Salty Water

Gullies on Mars suggest the presence of flowing salty water on the surface today, potentially indicating near-surface aquifers.

Viking Landers

The Viking landers searched for Martian life in 1976 but found no evidence. However, life might have existed on Mars in the past.

Divergent Planetary Evolution

Earth, Venus, and Mars have diverged in their evolution from similar beginnings, and understanding this is crucial for protecting Earth's environment.