Facts for kids: Where does the Moon come from?

The moon

Here’s a picture I took of the moon.

At an approximate distance of 400,000 kilometres (250,000 miles) from Earth, the Moon is the fifth largest moon in the Solar System. Its gravitational pull creates ocean tides, influences the length of the day, and has played a role in the development of the calendar. But where does the moon come from?

There are competing theories as to the origin of the Moon but the leading candidate is that of a cosmic collision. It is believed that the early Earth collided with a Mars-sized body called Theia about 4.527 billion years ago.

During the early stages of the solar system collisions between planets, asteroids and proto-planets are believed to have occurred on a regular basis. The sun was surrounded by an accretion disc of rock, dust and ice. The gravitational influence of large bodies within the disc scooped up the smaller bodies which, causing the large bodies to increase in size while clearing their orbits of anything significant in their paths.

The collision between Earth and Theia is resulted in an enormous explosion that transformed the surface of both into magma.

The impact was so immense that material from the two was ejected into space, forming an accretion disc around the Earth. Within a hundred years the Moon was formed from the debris.

Short answer: The Moon was formed when an object roughly the size of Mars smashed into Earth. A huge amount of rock was sent into space, and gravity caused it to group together into what we call the Moon.

Facts for kids: Where is the hottest place on Earth?

Hottest place on Earth

Death Valley has a habit of living up to its name.

The hottest place on earth is Death Valley in California’s Mojave Desert. Death Valley’s Furnace Creek holds the record for the highest confirmed air temperature in the world, recorded as 134 °F (56.7 °C) on July 10, 1913.

Death Valley’s status as the hottest place on Earth is a result of geography, atmospheric pressure, and altitude.

The valley is flat, below sea level and enclosed by mountains. The sun’s heat reaches the ground, and is absorbed by the barren soil and rock of its surface. Heat radiates from the surface of the valley, and the surrounding air increases in temperature. The air consequently rises and cools as it gains altitude.

But the cooler air cannot escape the valley due to the surrounding mountains and the higher atmospheric pressure of the colder air above. The recently cooled air descends back down into the valley where it is reheated by the sun. Reheated, the air rises once again but is kept hemmed within the valley by as the process repeats.

The result is a high surface temperature and hot winds that cause conditions akin to a drought.

Short answer: Death Valley is the hottest place in the world. The Native American Timbisha tribe have lived there for at least 1000 years, but tourists and adventurers regularly die from dehydration and misadventure. You might want to avoid going there in summer with a bag of peyote.

Facts for kids: New claim for the coldest place on earth

The coldest place on Earth

The coldest place on Earth is a horror movie waiting to happen.

NASA claims a high ridge on the East Antarctic Plateau is now the coldest place on earth. A temperature of -93.2° Celsius (-135.76 F) was recorded on 10 August 2010 via satellites. This record is unlikely to be recognised because the World Meteorological Organisation only recognises temperature recordings from ground-based weather stations.


Officially the coldest place on Earth is the Russian research facility known as Vostok Station. On July 21 1983 it experienced the lowest recorded temperature of -89.2 degrees Celsius (-128.56 F).

The station is 3,488 meters (11,444 ft) above sea level and is one of the most isolated research stations on the Antarctic continent. Winter temperatures average about −65 °C (−85 °F). Summer temperatures average around −30 °C (−22 °F). So, no, you won’t want to go sunbathing.

Feel like visiting? You might want to go somewhere else on your adventure holiday. Apart from the cold, the atmosphere is thinner due to altitude. There is very little moisture in the air that you will breathe, and polar night lasts around 130 days, from mid April to late August. Scientists and researchers who visit may take up to two months to acclimatise to the conditions. Common ailments of newcomers include headaches, eye twitches, ear pains, nose bleeds, perceived suffocation, sudden rises in blood pressure, loss of sleep, reduced appetite, vomiting, joint and muscle pain, arthritis, and weight loss.

That said, Vostok is an interesting analog to Mars. The Spirit Rover equatorial exploration of Mars reported highs of about 35 degrees C. (95 degrees F.) in summer to lows of -90 degrees C. (-130 degrees F.) in winter.

Short answer: The coldest place on Earth is Vostok Station, Antarctica. The temperature fell to -89.2 degrees Celsius (-128.56 F) on July 21 1983.