Earth Sciences

This page covers everything about the earth and its history.  It includes geology and meteorology (but see also Minerals).

Numbers

Age of the Earth (and the rest of the solar system)		4.55 billion years
Life on Earth began about		4 billion years ago
Circumference of the Earth at the Equator		24,901 m (40,074 km)
Mean diameter of the earth		7,918 m (12,743 km)
Mean radius of the earth		3,959 m (6,371 km)
Approximate radius of the (solid) inner core		800 m (1,300 km)
Approximate thickness of the (liquid) outer core		1,400 m (2,250 km)
Approximate thickness of the mantle		1,800 m (2,900 km)
Depth of the crust (thinnest in the ocean beds)		3 – 45 m (5 – 70 km)
Speed at which the Earth moves relative to the sun		66,250 mph
For 1,000 feet rise in altitude: temperature drops by		1o Fahrenheit
Sea water (of typical salinity) freezes at approximately		–2o C
Approximate altitude at which atmospheric pressure is about half that at sea level		3.4 miles (5.5 km) 18,000 ft (5,500m)
Fog and mist: visibility boundary (less is fog, more is mist)		1,100 yards
760 millimetres of Mercury		1 atmosphere (bar)
Depth of snow equal to 1 inch of rain		1 foot
Latitude of the Equator		0o
Latitude of the North and South Poles		+/– 90°
Longitude of Greenwich (the Prime Meridian)		0°
Longitude of the International Date Line (mainly)		180°
Latitude of the Tropics (Cancer is North, Capricorn is South)		+/– 23° 26'
Latitude of the Arctic/Antarctic circles		+/– 66° 34'

Notice that the latitudes of the tropic and the polar circles (in each hemisphere) add up to 90°.

Latitude of Lizard Point, the most southerly point of Great Britain		49° 57'
Latitude of London		51° 30' 25"
Latitude of Dunnet Head, the most northerly point of Great Britain		58° 40' 21"
Degrees of longitude in a 1–hour time zone (360 / 24)		15
Percentage of the earth's surface covered by water		71
Number of points of the compass, in European tradition		32

Types of Rock

Type of rock formed when lava cools: e.g. granite, basalt, peridotite		Igneous
Rocks that have been restructured by heat or pressure: e.g. gneiss, slate, marble, schist, quartzite		Metamorphic
Rocks formed by the deposition of the remains of other rocks or other materials, or by precipitation from solution: e.g. limestone, chalk, sandstone, shale		Sedimentary

Layers of the Atmosphere

From ground level, to between 7 and 11 miles	Where weather takes place; heated at lower levels by the ground, which absorbs heat from the sun, but temperature decreases with altitude. Thinner at the poles		Troposhere
10–25 miles	Heated from above by absorption of ultraviolet radiation from the Sun, which causes temperature to rise with altitude; includes the Ozone Layer		Stratosphere
25–50 miles	Temperature decreases with increasing altitude		Mesosphere
50–430 miles	Characterised by ionisation caused by ultraviolet radiation – includes most of the Ionosphere (which extends down into the upper Mesosphere). Temperatures increase with altitude due to absorption of highly energetic solar radiation by the small amount of residual oxygen still present		Thermosphere
Above 430 miles	Where the atmosphere thins out into space. Lower limit varies from about 300 miles to 600 miles; upper limit is about 6,000 miles		Exosphere
47–600 miles	The region that's ionised by solar radiation (the solar wind); starts in the upper Mesosphere, coincides with the Thermosphere. Divided into three layers, of increasing ionisation: the D–region (47–60 miles), the E–region (60–95 miles), and the F–region (95–600 miles)		Ionosphere

Named Winds (and Storms)

Northerly katabatic (downslope) wind of the Adriatic and neighbouring countries – name comes from the same root as the Greek word for the north wind		Bora
Hot, dry wind in the southern Australian desert in summer		Brickfielder
Strong, often persistent and dry south–easterly wind that blows from spring to late summer; believed to clear Cape Town of pollution and 'pestilence'		Cape Doctor
The warm, dry wind that blows down the eastern (inland) side of the Rocky Mountains at the end of winter – named after the native people of the north–western USA		Chinook
Cool sea breeze of summer afternoons in Western Australia		Fremantle (Freo) Doctor
Warm wind from the Sahara to the Mediterranean coast of Africa		Harmattan (Doctor)
The British Isles' only named wind: a strong north–easterly that blows down the south–west slope of Cross Fell, Cumbria (the highest summit in the Pennines)		Helm Wind
Wind that brings warm weather to Egypt and Sudan in spring (March–April)		Khamaseen (Khamsin)
Easterly wind that blows in the Western Mediterranean		Levanter
Cold, dry wind in the Mediterranean provinces of France and up the Rhone valley		Mistral
Seasonal winds on and around the Indian subcontinent; name comes from an Arabic word meaning "season"		Monsoon
The strong westerly winds found in the Southern Hemisphere, generally between the latitudes of 40 and 50 degrees		Roaring Forties
The warm, dry wind that blows onto the Mediterranean from North Africa, sometimes reaching southern Italy		Scirocco

Name given to the first UK storm to be officially named by the Met Office (which hit northern Scotland in 2015)			Abigail
Name of the hurricane that devastated New Orleans (among other places) in 2005			Katrina

The Beaufort Scale

The following definitions are those used by the UK Meteorological Office, which describes the Beaufort scale as "an empirical measure for describing wind intensity based on observed sea conditions".

Rather oddly, given this information, the Met Office also gives a scale of "seastates", which does not exactly correspond to the wind forces.

The most important thing for quizzers is to be able to relate the wind force numbers to their descriptions. Other information in the table below may come up occasionally, but I include it here mainly as background information.

The wave heights are maximums (or maxima, if you prefer), in metres.

Force	Knots	mph		Description	Wave height	Seastate	Description
0	1	1		Calm	0	0	Calm (glassy)
1	3	3		Light air	0.1	1	Calm (rippled)
2	6	7		Light breeze	0.3	2	Smooth (wavelets)
3	10	11		Gentle breeze	1.0	3	Slight
4	16	18		Moderate breeze	1.5
						4	Moderate
5	21	24		Fresh breeze	2.5
6	27	31		Strong breeze	4	5	Rough
7	33	40		Near gale	5.5
						6	Very rough
8	40	46		Gale	7.5
						7	High
9	47	54		Strong gale	10
10	55	63		Storm	12.5	8	Very high
11	63	72		Violent storm	16
12	64+	73+		Hurricane		9	Phenomenal

Sea Areas

"The Shipping Forecast, issued by the Meteorological Office" is a familiar and much–loved friend to many listeners of the BBC's Radio 4 – of whom I am one.

Some aspects of the Shipping Forecast – essentially those that refer to the broadcast rather than the weather, including the full list of areas in the order that they're read out – are covered on my Radio page.

Areas around the British coast: Cromarty, Forth, Tyne, Humber, Thames, Dover, Wight, Portland, Plymouth, Lundy, Irish Sea, Malin, Hebrides, Fair Isle

Similarly for Ireland: Lundy, Fastnet, Shannon, Rockall, Malin, Irish Sea

Number of sea areas		31
North and South Utsire are off the coast of		Norway
Fisher is off the coast of		Denmark
German Bight is off the coast of Germany and
Areas in the North Sea, with no coast		Viking, Forties, Dogger
Areas in the Atlantic, with no coast		Sole, Bailey
Most northerly area, and most westerly (and last to be mentioned)		South East Iceland
Most southerly		Trafalgar
The only shipping area that's named after a person (the founder of the Meteorological Office)		FitzRoy
Renamed FitzRoy in 2002 to avoid confusion with the Spanish area of the same name		Finisterre
Introduced 1955 when Dogger was split in two		Fisher
German Bight was known, until 1956, as		Heligoland
Merged with Hebrides around 1982		Minches
Introduced 1984 to co–ordinate with Norwegian forecasts – formerly part of Viking		North & South Utsire

There's more information, including an interactive map (check out the red areas for gale warnings) here on the Met Office's web site.

Climate Treaties

1997: established legally–binding obligations for developed countries to reduce their greenhouse gas emissions in the period 2008–2012		Kyoto Protocol
2012: amended the Kyoto Protocol to cover the period 2013–2020 (but never came into force)		Doha Amendment
2015: governs emission reductions from 2020; came into force on 4 November 2016		Paris Agreement

Other

Supercontinent that existed about 250 million years ago: postulated in 1912 by the German geophysicist Alfred Wegener; the name originated in 1928 at a symposium on his work (Wegener called it "the Urkontinent")		Pangaea
About 135 million years ago, Pangaea split into		Gondwana
		Laurasia

Shapes that indicate a warm front, on a weather map		Semi–circles
Shapes that indicate a cold front, on a weather map		Triangles

Caused by the reaction of sulphur dioxide and nitrogen oxide with water molecules in the atmosphere			Acid rain
Area of high atmospheric pressure			Anticyclone
The Greenwich Meridian crosses the Equator in (i.e. 0° latitude & 0° longitude)			(South) Atlantic Ocean (south of Ghana)
Scientific name for the Northern Lights			Aurora borealis
Scientific name for the Southern Lights			Aurora australis
Libyan city, where the highest ever temperature in the shade – 134°C – was recorded in 1922			El Aziza (Al Aziziyah)
Those parts of the Earth and its atmosphere that are able to support life			Biosphere
Enlarged shadow seen against cloud when the sun is low – named after the highest of the Harz Mountains in northern Germany where it is frequently seen			Brocken spectre (or bow)
Chalk and limestone consist essentially of (chemical compound)			Calcium carbonate
The process by which large chunks break away from glaciers and float off into the sea as icebergs or other ice debris			Calving
The highest type of cloud – name is from Latin for a lock of hair – colloquially known as "mare's tails"			Cirrus
Measured in oktas (an okta is one eighth of the sky)			Cloud cover
Lignite, bituminous and anthracite are the three types of			Coal
Rock fragment between 65mm and 256mm diameter (i.e. larger than a pebble but smaller than a boulder)			Cobble
The effect of the earth's rotation on winds, currents, and other objects on the surface; also a cause of the earth's magnetic field			Coriolis effect
Cloud type normally associated with thunderstorms			Cumulonimbus
An area of low atmospheric pressure; also the name used for a hurricane in the Indian and South Pacific oceans (cf. Typhoon)			Cyclone
Early June to mid–August: the period when Sirius rises with the Sun, characterised by hot, stifling weather; known since Roman times as the			Dog Days
Name given by sailors to the belt of low pressure around the Equator – characterised by light winds and calms, but occasional sudden storms – caused by the meeting of trade winds			The Doldrums
Tectonic plate (see Sets) on which Great Britain is situated			Eurasian
Calm centre of a hurricane			Eye
Group of minerals said to make up 60% of the Earth's crust			Feldspars
Theory that the earth adapts itself in order to survive, in the same was as a living organism – formulated in the 1960s by the English independent research scientist James Lovelock, and named after the Greek supreme goddess of Earth			Gaia Hypothesis
Mica, feldspar, quartz: varieties of			Granite
The best–known result of thermohaline circulation			Gulf Stream (or North Atlantic Drift)
Campbell–Stokes Recorder measures			Hours of sunshine
Cold Northerly current on the Pacific coast of Chile and Peru			Humboldt Current
Amount of water vapour in the atmosphere			Humidity
Oceans, lakes, atmospheric water vapour, etc.: generic name			Hydrosphere
Milankovitch Hypothesis is concerned with			Ice age(s?)
Jack o'Lantern, Will o'the Wisp (mysterious lights that appear at dusk or twilight, especially over marshy or boggy ground): scientific name			Ignis fatuus
The plasma in the earth's atmosphere (mesosphere and thermosphere) which affects radio propagation and thus reflects radio waves back to earth			Ionosphere
The most abundant element in the planet Earth (34% by weight); makes up 80% of the core			Iron
Lines of equal pressure			Isobars
Lines of equal depth (of water)			Isobaths
Lines of equal sunshine hours			Isohels
Lines of equal rainfall			Isohyets
Lines of equal depth of cloud cover			Isonephs
Lines of equal temperature			Isotherms
Coldest month of the year in Britain			January
Warmest month of the year in Britain			July
High–velocity winds at altitudes of 30,000 to 50,000 feet (6 to 10 miles)			Jetstream
Layer in the ionosphere, altitude about 56 to 90 miles, that deflect radio waves and thus makes round–the–world transmissions possible; named after the US and British physicists who independently predicted its existence in 1902; detected 1924 by Sir Edward Appleton; now called the E region			Kennelly–Heaviside layer
Ribbon, rocket, streak and sheet are types of			Lightning Lightning
A fulgurite is an irregular, branching, often foamy hollow tube of silica glass, formed by the melting of quartz sand at very high temperatures, as a result of
Crust and solid outermost layer of mantle (down to approx 100km)			Lithosphere
The volume of space surrounding a planet, controlled by the planet's magnetic field			Magnetosphere
Semi–molten (plastic) layer between the outer core and the crust			Mantle
Boundary between the Mesosphere and the Thermosphere (altitude about 50 miles)			Mesopause
Tunguska, Siberia, 1908			Meteorite
Ambitious American attempt (1961) to drill through the Earth's crust into the Mohorovičić discontinuity, providing an Earth Science complement to the Space Race – from Guadalupe Island, off Baja California (Mexico – note: not Guadaloupe)			Project Mohole
The boundary between the crust and the mantle, marked by a rapid increase in the speed of earthquake waves			Mohorovičić (Moho) Discontinuity
Magma			Molten rock
Average length of one minute of arc on a great circle			Nautical mile
Tides with the least variation (highest low waters, lowest high waters) – occurring when the influences of the sun and moon are in opposition to one another			Neap
Second most abundant element in the earth's core (80% of which is iron)			Nickel
Rain cloud (from the Latin for a cloud or rainstorm)			Nimbus
Popular name for the Southern Oscillation, a warm Pacific current periodically (average once every 5 years) causing unpredictable worldwide weather conditions			El Niño (La Niña)
78% of the Earth's atmosphere is			Nitrogen
Amphidromic points (there are three in the North Sea)			No rise and fall in tides
Points on the Earth's surface where all lines of longitude meet			North and South Poles
Formed when a cold front overtakes a warm front; represented on a map by alternating semicircles (representing the warm front) and triangles (cold front)			Occluded front
Abyssal, Bathyl, Hadal: zones of			Ocean depth
21% of Earth's atmosphere (most of the 22% that isn't nitrogen) is			Oxygen
Second only to iron in the earth itself, by weight (28%)
The part of the stratosphere that absorbs ultra–violet rays			Ozone layer
Soil that's been below 0°C for two years or more			Permafrost
Nival zone (on a mountain)			Permanent snow cover
Rain, snow, hail etc.: generic name, to meteorologists			Precipitation
Term used in cartography for an attempt to reproduce the three–dimensional surface of the earth in two dimensions			Projection
You would find (in ascending order) an understory layer, a canopy layer and an emergent layer in a			Rainforest
Second most abundant material in the Earth's crust, after feldspar			Quartz
Hyet– (e.g. isohyet, hyetograph)			Rainfall
'Haboob' is a name (originating in Sudan) for a			Sand storm (or dust storm)
The word 'eustatic' refers to worldwide changes in			Sea level
The main constituent of the rock that forms the earth's mantle and crust (various compounds, of silicon, oxygen, one or more metals, and sometimes hydrogen)			Silicates
The second most abundant element in the Earth's crust (27% – oxygen 49%)			Silicon
Prevailing wind direction in the British Isles			South–West
Luminous electrical discharge from lightning conductors, ships' masts etc. in a thunderstorm			St. Elmo's Fire
Tectonics: the movement of one plate sliding under another			Subduction
The ocean or sea that was formed when Pangaea split to form Laurasia and Gondwanaland – named after the wife of the sea god Oceanus, in Greek mythology			Tethys (Sea or Ocean)
Imaginary lines linking the furthest points from the Equator where the Sun can be directly overhead (at midday)			Tropics
An exceptionally large wave, typically following an earthquake or a volcanic eruption on or below the ocean bed (from a Japanese word meaning 'harbour wave')			Tsunami
Boundary between the troposphere and the stratosphere – where temperature starts to increase with height, instead of decreasing			Tropopause
The name used for a hurricane in the North Pacific (cf. Cyclone)			Typhoon
Two belts of charged particles, held in place by the Earth's magnetic field, above the magnetosphere – confirmed in 1958 by the Explorer I and III space missions – named after the US space scientist who suggested that Geiger counters should be taken on those missions			Van Allen belts
Aphotic zone (lakes and oceans)			Very deep (no light)

© Haydn Thompson 2017–19