Earth's Atmosphere
Measured in millibars, hPa, Pa or inches of mercury, this force exerted by the weight of the air decreases with altitude and is commonly measured using a barometer.
What is atmospheric pressure?
These seismic waves cannot travel through liquids, providing key evidence that Earth's outer core is in a molten state.
What are S-waves (secondary waves)?
These large, dark, basaltic plains on the Moon’s surface formed from ancient volcanic activity and were once mistaken for seas.
What are lunar maria?
This NASA mission, launched in 1969, was the first to successfully land humans on the Moon.
What is Apollo 11?
This phase occurs when the Moon is positioned between the Earth and the Sun, making it nearly invisible from Earth.
What is a new moon?
In this lowest layer of the atmosphere, temperature decreases with altitude at an average rate of about 6.5°C per kilometer.
What is the troposphere?
While the lithosphere is rigid, this underlying region of the mantle behaves plastically, allowing tectonic plates to move.
What is the asthenosphere?
These permanently shadowed regions near the Moon’s poles have been found to contain water ice, possibly useful for future lunar missions.
What are polar craters?
This Soviet spacecraft became the first to fly past the Moon in 1959, marking a major milestone in space exploration.
What is Luna 1?
These exceptionally high and low tides occur when the Earth, Moon, and Sun align, strengthening the gravitational pull on Earth’s oceans.
What are spring tides?
This atmospheric layer, located between 10 km and 50 km above Earth’s surface, contains the ozone layer, which absorbs harmful UV radiation.
What is the stratosphere?
This slow movement of rock in the mantle is the primary driving force behind plate tectonics.
What is mantle convection?
These seismic events on the Moon can last for hours and are often triggered by tidal forces from Earth.
What are moonquakes?
In 1966, this Soviet probe became the first spacecraft to achieve a controlled soft landing on the Moon.
What is Luna 9?
This process, caused by the interaction between the ocean tides and the seafloor, converts kinetic energy into heat and contributes to Earth’s rotational slowing.
What is tidal friction?
This large-scale circulation pattern, consisting of rising air near the equator and descending air at about 30° latitude, drives the trade winds.
What is the Hadley cell?
The movement of molten iron and nickel in this layer generates Earth's magnetic field through the dynamo effect.
What is the outer core?
This fine, powdery layer of fragmented rock and dust covering the Moon’s surface was created by constant meteoroid impacts.
What is lunar regolith?
This Apollo mission, the first to carry a geologist to the Moon, returned the largest amount of lunar samples to Earth.
What is Apollo 17?
As Earth’s rotation slows due to tidal interactions, the Moon gradually moves in this direction relative to Earth.
What is away (or outward)?
Although present in much smaller amounts than carbon dioxide, this greenhouse gas is about 25 times more effective at trapping heat over a 100-year period.
What is methane?
Named after a Croatian seismologist, this boundary marks the transition between Earth's crust and mantle.
What is the Moho (Mohorovičić Discontinuity)?
This is the name of the largest and deepest impact basin on the Moon, located on its far side.
What is the South Pole-Aitken Basin?
This NASA program, named after a mythological figure, aims to return humans to the Moon and establish a sustainable lunar presence.
What is Artemis?
In the distant future, tidal interactions will cause Earth’s rotation and the Moon’s orbit to reach this state, where one side of Earth always faces the Moon.
What is tidal locking?