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meteoroid = a small rocky body moving in the solar system

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meteoroid = a small rocky body moving in the solar system

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crater = large, round pits on the surface of the moon

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crater = large, round pits on the surface of the moon

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maria = dark, flat areas on the surface of the moon 

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maria = dark, flat areas on the surface of the moon 

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ExploreLearning : Get hands-on, minds-on in math and science

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Phases of the Moon Gizmo | ExploreLearning

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Understand the phases of the Moon by observing the positions of the Moon, Earth and Sun. A view of the Moon from Earth is shown on the right as the Moon orbits Earth. Learn the names of Moon phases and in what order they occur.

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phases = there are 8 different phases of the moon that can be viewed from Earth.  These represent the names given to points in the Moons orbit around Earth.  The phases are connected to the position of the Moon in relation to the Sun.

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phases = there are 8 different phases of the moon that can be viewed from Earth.  These represent the names given to points in the Moons orbit around Earth.  The phases are connected to the position of the Moon in relation to the Sun.

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U1 L6 Completed Earth's Moon Guided Notes

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The world is remembering 50 years since US astronauts Buzz Aldrin and Neil Armstrong became the first people to walk on the Moon.

Neil Armstrong stepped on to the surface of the Moon on 20 July 1969. As he did so, he spoke the famous words: "That's one small step for man, one giant leap for mankind."

A camera was able to transmit the moment to around 650 million people who were watching on television.

Armstrong was closely followed by fellow astronaut Buzz Aldrin, who described the Moon as "magnificent desolation".

They spent 21 hours on its surface, including a seven-hour sleep, before returning to Earth.

Find out more about the mission below.

The simple reason is that it had never been done before - and it was a big ambition for countries, and their space programmes, to be the first to land a human on the Moon's surface.

In the run-up to the Moon landing, the US was competing with the Soviet Union in something called the space race. This was a competition between them to be the first to complete missions exploring the world outside the Earth's atmosphere.

This race started when the Soviets - the US's enemy during the Cold War - launched the first Soviet Sputnik satellite in 1957.

Then, Soviet cosmonaut Yuri Gagarin became the first human in space on 12 April 1961.

The Americans wanted technological superiority - and it looked like the Soviets were winning in the space race.

So, in 1962, US President John F Kennedy announced a big ambition, in a speech which is now very famous.

"We choose to go to the Moon!" he said.

US space agency Nasa invested lots of money (around $25 billion, which is around £20 billion) and effort into making this happen. The mission would come to be known as the Apollo programme and its goal was to land humans on the Moon and bring them safely back to Earth.

About 400,000 people worked on it.

The Moon landing in numbers

The Moon is about 240,000 miles from Earth - so the Apollo mission was not going to be an easy task. It was also a dangerous mission.

The Apollo mission that would eventually land a man on the Moon - Apollo 11 - was not the first.

Apollo 8 and 10 entered lunar orbit but didn't achieve the program's goal, while during Apollo 1, the crew of three tragically died in a launch pad fire.

On the morning of 16 July 1969, astronauts Buzz Aldrin, Neil Armstrong and Michael Collins blasted off aboard a Saturn 5 rocket, which propelled them out of Earth's gravity.

The Apollo 11 mission had three spacecraft: the Command Module Columbia, a Service Module and the Lunar Module Eagle.

It took four days, six hours and 45 minutes to get to the Moon.

The lunar module landed on the Moon at 8:17pm on 20 July 1969.

Houston, Tranquillity Base here. The Eagle has landed

Neil Armstrong, Message to Mission Control in Houston, Texas

While astronauts Armstrong and Aldrin descended to the Moon in the Eagle module, Michael Collins remained alone in Columbia. For 28 hours, he served as a communications link and photographed the lunar surface.

By the time the crew landed back on Earth, the mission had taken 8 days, 3 hours, 18 minutes and 35 seconds.

Sadly, Mr Kennedy never got to see his dream come true as he was killed in 1963.

In the end, it was President Nixon who made the first telephone call to the Moon and the longest distance phone call (some 240,000 miles) ever made.

While many say a big part of the lunar landing was technological superiority in the space race, there were other reasons it was such an important mission.

These including establishing the technology to do it in the first place (which could have other uses), carrying out scientific exploration of the Moon, and developing human capability to work in a lunar environment.

The astronauts carried out important experiments while on the surface, and they picked up bits of Moon dirt and rocks to bring back to Earth to be studied.

They also left behind an American flag, a patch honouring the fallen Apollo 1 crew and a plaque on one of the Eagle's legs.

It reads: "Here men from the planet Earth first set foot upon the moon. July 1969 A.D. We came in peace for all mankind."

Where were the women?

Looking at the coverage of Apollo, you might think that it is just white men who made the Apollo 11 mission a reality.

The astronauts were all men, the mission controllers were all men and even the TV anchors were male.

But there were thousands of women supporting the mission.

Instrumentation controller JoAnn Morgan was the only woman in Apollo 11 launch control at Cape Canaveral. As an engineer, she was responsible for 21 channels of communications, as well as the health and welfare of all the monitoring systems for the Saturn 5 rocket, which launched the astronauts into space.

Mathematician Katherine Johnson was also part of Nasa and helped to calculate the trajectory for the 1969 Apollo 11. She was one of a group of female African-Americans who worked at Nasa and whose amazing story is told in the film Hidden Figures.

The US would go on to complete six crewed missions to the Moon, which landed a total of 12 astronauts (all men) on its surface.

The Apollo missions, as they were called, all took place from 1969 to 1972 - from Apollo 11 right up to Apollo 17.

All of the missions successfully landed astronauts on the Moon apart from Apollo 13, which was supposedto go to the Moon, but had technical problems.

A total of 12 people have walked on the Moon - Neil Armstrong, Buzz Aldrin, Pete Conrad, Alan Bean, Alan Shepard, Edgar Mitchell, David Scott, James Irwin, John Young, Charles Duke, Eugene Cernan and Harrison Schmitt.

The last people walked on the Moon in 1972.

Since then, lots of countries have landed probes on the Moon, but none with people aboard.

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Apollo 11 Moon landing: Everything you need to know

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It has been 50 years since Apollo 11 first put a man on the Moon. Neil Armstrong stepped on to its surface on 21 July 1969. Find out more about how it happened.

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Solar System Exploration Research Virtual Institute

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The moon's surface is riddled with craters ranging in size and structural complexity, and billions of years ago before life emerged, the Earth looked the same way.

"The bottom line is, everything that happened on the moon happened on the Earth," said David Kring, crater expert and team leader for Center for Lunar Science and Exploration. "The Earth used to look just like that."

But Earth has several things the moon doesn't - an atmosphere and liquid water that cause erosion. And the trump card, plate tectonics, that recycles much of the planet's crust over millions of years and smooths away blemishes left by cosmic impacts. As a result, there are only around 160 known impact craters in existence today (though there are surely more that haven't been discovered).

Craters come in two flavors: those that aren't caused by asteroids or comets, impact craters, are formed by powerful volcanic explosions.

Such outbursts can be violent enough that once the eruption is over, the volcano collapses in on its empty vacant magma chamber and forms a caldera, or volcanic crater.

Lake Toba in Sumatra, the largest volcanic structure on Earth, is an example of an enormous caldera that has filled with water over time.

Whereas volcanic craters arise from deep inside the planet, impact craters originate in outer space.

When a meteor makes it through Earth's atmosphere without burning up, it strikes the ground faster than the speed of sound.

"Something we don't understand very well on the geological side (of crater formation) is, we still find it difficult to determine the trajectory of impacting objects for most impact craters," Kring said. "We're still searching for a clue to deduce that."

But no matter at what angle it makes contact, the enormous amount of kinetic energy the projectile carries immediately transfers to the target rock it hits, triggering powerful shock waves.

Although craters look like imprints of a giant fist smashing the ground inward, impact shock waves have the opposite effect, which planetary scientists divide into three phases.

The compression stage of crater formation involves that initial exchange of energy between the projectile and the impact area.

During the excavation phase, the massive shock wave causes the projectile to simultaneously melt and vaporize, spewing plumes of searing hot rock vapor miles high into the atmosphere. The force can catapult chunks of molten and solid rock hundreds of miles from the impact site - this material is known as ejecta flow.

And so far, the crater formation process has only lasted a few seconds.

During the final modification phase, the remainder of ejecta partially refills and rings the crater site, and debris forms a rich mineral composite called breccia.

Larger, more forceful impact events will form complex craters in which the rock at the center of the crater rebounds from the downward pressure of the shock wave and uplifts into a mound-like formation.

But the environmental effects of impact crater formation go far beyond forming benign basins.

For instance, the famous Chicxulub crater in Yucatan, Mexico, is thought to be the site of the meteor impact that instigated the K-T event, which wiped out the dinosaurs in a mass extinction that affected much of life on Earth.

On Mars, meteor storms 100 million years ago may have literally shaken the Red Planet to the core and destroyed its magnetic field.

Even the crater-covered moon might be a chip off old Earth's block, an enormous shard shot into orbit following a giant impact event.

Given such drastic, far-reaching outcomes of space rock impacts, Kring said that studying crater formation holds the answer to understand not only how life on Earth began but also how it could be wiped away again in a future, perhaps inevitable, K-T event.

"There will be another Chicxulub-size impact event," he said.

Since tectonic plate movements has erased much of Earth's crater record, the answers to the lingering questions about crater formation and timelines lie in the "exquisitely preserved" craters on the moon.

But until NASA returns to the lunar landscape, researchers must rely on shockwave simulators, mathematical models and the well-worn geological formations on Earth to estimate how and when another impact event might occur.

"Where we're really going to get the answers - the gold standards of answers - is when we go back to the moon," Kring said.

Posted by: Soderman/NLSI Staff
Source: http://news.discovery.com/earth/how-are-craters-formed.html

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The moon's surface is riddled with craters ranging in size and structural complexity, and billions of years ago before life emerged, the Earth looked the same way. "The bottom line is, everything that happened on the moon happened on the Earth," said David Kring, crater expert and team leader for Center for Lunar Science and Exploration.

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What are the dark spots on the moon?

One of the main things you notice on the moon is that it has bright and dark areas across the surface.

Everybody's familiar with the man on the moon, right?

The dark areas are known as "mare" (or maria) which is the Latin word for "seas". They're called maria because early scientists believed they could see oceans on the moon. But the dark stretches on the surface of the moon were not oceans at all.

What the "maria" actually turned out to be were volcanic basins. They were created from the aftermath from ancient impacts billions of years ago. After the impacts, the craters filled with lava. Eventually, the lava cooled. These flat flood basalts formed smooth lunar maria.

The Sea of Tranquility Maria

One of the most famous maria is the Sea of Tranquility.

This was the landing site chosen by Apollo-11 in part because it was fairly smooth and level.

Apollo-11 is world renowned because it gave mankind its first-ever walk on the moon.

Not only for a landing site, but it also made an easy trek for Neil Armstrong.

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Lunar Maria: Volcanic Basins on the Moon - Earth How

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One of the main things you notice on the moon is that it has bright and dark areas across the surface. Everybody's familiar with the man on the moon, right? The dark areas are known as "mare" (or maria) which is the Latin word for "seas".