Vocab
Milankovitch Cycles
Earth’s Changes Over Time
Sunlight & Seasons
Ice Ages & Climate Shifts
Bonus questions!
100
What is obliquity?
The degree tilt of Earth’s axis
100
How long does precession take to complete a full cycle?
About 26,000 years
100
What happened to earth tilt between 130kya and 113kya
It decreased (tilt got smaller)
100
What is perihelion?
When Earth is closest to the Sun
100
What is a glacial period?
A cold period when ice sheets grow and cover more land
100
What happens to radiation at 65°N when Earth is tilted less?
Summer sunlight is weaker
200
What is eccentricity?
The shape of Earth’s orbit (how round or stretched it is)
200
How long does a full obliquity cycle take?
About 41,000 years
200
What happened to Northern hemisphere Summers from 25kya to 9kya
They became warmer
200
What is aphelion?
When Earth is farthest from the Sun
200
What is an interglacial period?
A warm period when ice sheets melt and retreat
200
What changes when Earth’s orbit becomes more elliptical?
The distance from the Sun changes more during the year
300
What is axial precession?
The wobble that changes the direction of Earth’s tilt
300
How long does eccentricity take to cycle?
About 100,000 years to 405,000 years
300
Why did summers get warmer AFTER 25kya?
Earth’s tilt increased and summer happened closer to perihelion
300
If NH summer happens at aphelion, what is summer like?
Cooler and weaker
300
What three Earth movements affect long-term climate?
Eccentricity, Obliquity, and Axial Precession
300
If asked to choose a glacial period, would you choose a peak at the top or one on the bottom?
A peak at the bottom indicates a glacial period
400
What does 65° north refer to in this unit?
The North Pole, a key location to measure some radiation and ice sheet behavior
400
Which Milankovitch cycle changes when seasons happen?
Axial precession
400
What effect did cooler summers at 113kya have on ice sheets?
Ice sheets began to grow (start of glacial period)
400
What combination could lead to melting ice sheets?
Summer during perihelion + greater tilt = strong summer sunlight
400
What happened to Earth’s climate between 25kya and 9kya?
It warmed, causing ice sheets to melt
Reasoning: the tilt increased & Earth at 65°N was at perihelion.
400
What kind of period did 150kya to 130kya transition to?
From glacial to interglacial
500
What happens when summer at 65° north gets less sunlight?
Ice sheets can grow, leading to glacial periods
500
Which Milankovitch cycle affects how extreme the seasons are?
Obliquity
500
What major shift happened around 9,000 years ago?
The last Ice Age ended; Earth entered the current interglacial period
500
What combination could lead to ice growth?
Summer during aphelion + low tilt = weak summer sunlight
500
Why do scientists focus on 65°N when studying ice ages?
Sunlight at 65°N in summer helps predict ice melting or growth
500
What does KYA stand for?
Thousand years ago