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Our Celestial Companion (and others)

Saturday April 6, 2019:

Our Natural Satellite: Moon, Lune, Luna


Basic Facts:

- 5th largest natural satellite in solar system

- 2nd densest natural satellite in solar system

- Diameter of 3,474 km (2,159 miles)

- Average distance from Earth: 384,403 km (238,857 miles)

- Distance away at apogee: 406,700 km (252,700 miles)

- Distance away at perigee: 356,500 km (221,500 miles)

- 4.5 billion years old

- 27.3 days orbital period (also 1 lunar day) = 1 side always faces Earth

- 1/6 gravity of Earth's

- Composition similar to Earth

- Last visited by humans in 1972 (time to go back)!


Welcome to exploring the cosmos with TeBe Photographs! We begin locally with the moon (and moons) and will expand from there. Our natural satellite has served with us since almost the beginning of Earth, about 100 million years after formation of the solar system. In theory, a Mars-sized object slammed into the early Earth causing massive debris to be ejected into space. Earth's gravitational pull kept that debris in orbit and the debris had enough mass (thus gravity) to become sphere-like. We got the moon. For a planet the size of ours, we got a large moon. It is 27% Earth's size and is actually bigger than Pluto. (Pluto's diameter is 2,377 km, or 1,475 miles.) The moon has an atmosphere, believe it or not, but it is very thin so you will not see it. Eventually in the far distant future, we will unfortunately lose our companion to deep space. Every year, the moon orbits slightly further and further away from Earth (about 4 cm). In that future, the apparent size of the moon from Earth's surface will be smaller. Therefore, the tides will have a lesser difference between high and low, and total solar eclipses will not be a thing. Though, the oceans will be boiling away as the sun ages and expands toward Earth's orbit, thus tides will not be a thing either. (End of the sun topic is for another time.) This timeline is in the order of billions of years from now, so no worries. On the bright side, the Andromeda Galaxy will be colliding with our Milky Way providing the night sky with spectacular views compensating for moon loss. Aside from that, in the near-future (2020s), humans plan of returning to the moon and this time to stay establishing permanent bases. (Good news, water exist on and in the moon.) This would be the stepping stone for getting people to Mars. The moon will be used for research, mining, and training. There is a lot we can learn from our celestial companion.

Much more on Luna below.


Information has been sourced from space.com.

Visit the link below for more information about our moon:

https://www.space.com/55-earths-moon-formation-composition-and-orbit.html



As you may be aware, the planets (and dwarf planets) carry their system of natural satellites. Our moon is only 1 of at least 193 others in this solar system. Most are small and not spherical shaped. Only 19 of them (including our moon) are big enough to be gravitationally molded into sphere-like objects. If those 19 were orbiting the sun instead, they would be considered planets or dwarf planets. The 19 alone offers a wide variety of worlds from the volcanic moon of Io (Jupiter) to the thick hazy atmosphere of Titan (Saturn's largest) to snowing nitrogen (N) on Triton (Neptune's largest). The largest of the natural satellites is Ganymede, of Jupiter, with a diameter of 5,268 km (3,273 miles). Both Ganymede and Titan are larger than Mercury. (Titan's diameter is 5,149 km, or 3,200 miles, and Mercury's is 4,879 km, or 3,032 miles.) Titan is the only moon in our solar system to have a planet-like atmosphere. Europa (Jupiter) is known to host an underground liquid water ocean. The best part is that it is likely not alone for that. Possibilities for subterranean oceans could exist in Ganymede, Titan, and Enceladus (Saturn). Based on the past few lines, you notice the variety of worlds. More on these moons later! Below graphic are the currently confirmed number of moons for each world.


Comparison from NASA

Number of Moons:

- Mercury (0)

- Venus (0)

- Earth (1)

- Mars (2)

- Ceres* (0)

- Jupiter (79)

- Saturn (62)

- Uranus (27)

- Neptune (14)

- Pluto* (5)

- Haumea* (2)

- Makemake* (1)

- Eris* (1)

Total: 194 confirmed

*dwarf planet


Natural satellites do not only exist in our solar system, they most likely exist in others too. These would be called extrasolar moons (exomoons). As moons orbit planets, exomoons orbit exoplanets. The possibilities are limitless when it come to diversity of worlds that exist. More on exo stuff at another time!


Artist impression of an exomoon in orbit around a hypothetical Saturn-like exoplanet.

Inspire to imagine, explore, and capture the moment (space edition)


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06 abr 2019

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