The Earth and Moon

In our night sky, there is one celestial body that is easy spot – the moon. Like a large, natural satellite, the moon orbits around our Earth and is brighter than any regular nighttime cosmic object. So what is the difference between our Earth and the moon? Here are some characteristics that distinguish these differences along with some similarities that you can share with your Cadets at home.

Photo by Blatant World

Photo by Blatant World

The first major difference is our atmosphere here on Earth. It holds in the essential gasses we need to breath and helps to distribute thermal energy so that our planet does not get too hot or too cold. It is an important part of what makes Earth livable. The moon has a very thin atmosphere, which causes wild temperatures. On the moon during the day it can exceed 200°F and can drop to as low as -280°F at night! That’s too hot and too cold for any human, plant or animal from Earth to live comfortably.

Gazing at the moon in the night sky, it is hard to tell how big it really is. It is actually only a little over a quarter the size of our Earth, which is smaller than all of the planets in our solar system, with the exception of the dwarf planet, Pluto. But, compared to its counterpart during the day, why does the moon seem about the same size as the sun? Not only is the moon 400 times smaller, but also it is also 400 times closer to the Earth than the sun is! This explains why they look similar in size in our sky.

Believe it or not, the moon wasn’t always a fixture that orbited the Earth. So how did it get there? Scientists believe that the moon was formed from a huge collision that blasted a chunk off of the Earth. The debris was caught in orbit and eventually formed the moon.
It is true that the moon brightens up our night sky, but that is not the only thing it helps Earth with. Acting along with the sun, the moon’s gravitational forces are responsible for our ocean’s high and low tides.

The Earth and the moon are very different in size, atmosphere, temperature, and even terrain. The Earth is a unique planet that supports life and the moon helps the Earth support that life. So although very different, the moon serves a beneficial purpose as it orbits the Earth.

Europa – Our Potential Habitable Environment

What is the first criterion to defining a habitable environment for humans? Water to sustain life. Through NASA’s Hubble Space Telescope, scientists were able to observe water vapor above the south polar region of Europa, providing the first solid evidence of the existence of an ocean under Europa’s icy crust.

Photo by Lunar and Planetary Institute

Photo by Lunar and Planetary Institute

Researchers are able to speculate that the water vapor is most likely generated when water plumes erupted on the surface. If these findings are proven to be true, this would make Europa the second moon in the solar system known to have water vapor plumes. Also, the evidence provides a general idea of the chemical makeup of Europa and its potential of becoming a habitable environment, without digging through the layers of ice.

Photo by NASA Goddard Space Flight Center

Photo by NASA Goddard Space Flight Center

Since this moon has a strong gravitational pull, majority of the -40°F vapor would fall back onto the surface, rather than escaping into space. This new observation, if confirmed, can demonstrate the reliability and power of the Hubble Space Telescope, and its ability to explore new worlds for potentially habitable environments in our solar system.

Saturn’s Moon May Provide Clues to the Search for Space Water

Scientists have received the latest clues to aid their hunt for water in outer space with photographs taken by the Cassini spacecraft. Images of Saturn’s moon, Dione, focus on the 500-mile-long mountain Janiculum Dorsa—a landmark scientists use to compare Dione to Saturn’s geyser moon, Enceladus. Using Janiculum Dorsa along with other findings, researchers speculate that Dione may have once had a geologically active subsurface ocean.

dione_cassini_bigDiscovering subsurface oceans on Saturn’s moons Enceladus and Titan, Jupiter’s moon Europa, and now potentially Dione have led scientists to believe that there may be more worlds with water than previously imagined. These moons have played a crucial part in advancing the search for life beyond Earth.

Hints toward Dione’s possession of a subsurface ocean arose when Cassini detected a weak particle stream with its magnetometer. The spacecraft’s images suggest that a slushy liquid layer may exist beneath its icy crust along with fractures that spew water ice and carbon-containing particles. If the assumptions formed from Cassini’s images are correct and the moon does have a subsurface ocean, it would increase the moon’s chances for supporting life.

An intriguing clue toward Dione’s potential subsurface ocean is its mountain, Janiculum Dorsa. The mountain ranges from about 0.6 to 1.2 miles in height and appears to have deformed the crust beneath by 0.3 miles. Researchers believe that the deformation implies Dione has a warm surface, likely due to a subsurface ocean.

Cassini’s photographs have played a massive role in unlocking the mysteries of subsurface oceans on other worlds and the possibility of life in outer space. If scientists confirm the presence of a subsurface ocean on Dione, they may be able to find trends across multiple moons that could further their research into extraterrestrial life.

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