Our Solar System

Our Solar System

Earth, described by astronomer Carl Sagan as a “pale blue dot”, is part of the Solar System, which is only a tiny fraction of the Universe yet itself is almost larger than humans can understand.

Depending on certain definitions, the Solar System could be over one light-year (six trillion miles) across. A light-year is the distance light travels in a calendar year.

Light is the fastest thing ever detected, moving at 186,000 miles per second. At this incredible speed, it still takes over eight minutes for light from the Sun to reach Earth.

For clarification, say the Solar System is exactly one light-year across and the Sun is directly in the middle. In any direction, it would take light six months to reach the edge. Again, travelling at 186,000 miles per second.

Our Solar System is huge but is a negligible percentage of our Milky Way galaxy, let alone the Universe as a whole.

A “cosmic address” is an extended form of a common postal address. Though not an official record, my “cosmic address” (omitting the location of my house) would be Saddle Brook, New Jersey, United States, North America, northern and western hemispheres, Earth, Solar System, Milky Way, Local Group, Virgo Super-cluster, the observable Universe, the Universe.

Of course, that address is what English-speaking Earthlings would call it. Creatures in other parts of the Universe would have vastly different names for areas, assuming those beings exist and use the same system.

At that location, Earth is approximately 25,000 light years from the super-massive black hole at the center of the Milky Way. (Remember, one light year equals roughly six trillion miles.)

According to Greek mythology, the goddess Hera squirted her breast-milk across the sky when she was tricked and surprisingly woke up feeding an unknown child, who happened to be Hercules. This milk gave the demi-god (god/human hybrid) his incredible strength.

Many cultures call the Milky Way different names with various origin stories. The one above is what most Americans are taught.

A list of amazing facts about the Universe (from the Latin universum, meaning ‘whole’) would be extremely long. Below is some basic information about our Solar System and the parts that make it up. (Not including dark matter. Go here to read thoroughly about that and still not fully understand because it is pretty much insane.)

Many of the numbers in this article are rounded estimates for ease of understanding and lack of exact accuracy at such great distances. Also, the first five planets had unknown discoverers some time in antiquity since they are visible to the un-aided eye.

Enjoy!

THE SUN

DESCRIPTION
The gigantic ball of gas at the center of our Solar System is responsible for giving its planets light and warmth (to a degree, in some cases). The Sun creates light by nuclear fusion in its core. Gravity smashes four Hydrogen atoms together to make Helium, which produces energy in the form of light and radiation. Scientists think the Sun will die five billion years from now, when it will explode into a bigger, colder star. Life on Earth will not be possible since the planet will be engulfed by the new Sun. Have a nice day.

ROTATION (SPIN)
one Solar day = 27 Earth days at the equator; 31 days at the poles

SIZE
864,336 miles across
(about 10,917% of Earth’s diameter)
(an estimated 1.3 million Earths could fit inside the Sun)

AVERAGE SURFACE TEMPERATURE
9,980°F
(the core is estimated to reach 27 million °F)

GRAVITY COMPARED TO EARTH
2,790%
(200-pound human would weigh 5,580 pounds)

NOTABLE FACT
The Sun makes up over 99% of the mass in the Solar System, vastly overtaking the sum of everything written below.

 

MERCURY

NAMED FOR
The Roman god of messages and communication. (Greek equivalent is Hermes.)

AVERAGE DISTANCE FROM THE SUN
~ 36 million miles

ROTATION (SPIN) / REVOLUTION (ORBIT)
one Mercurian day = 59 Earth days
one Mercurian year = 88 Earth days

SIZE
3,032 miles across
(about 38% of Earth’s diameter)

AVERAGE SURFACE TEMPERATURE
261°F
(days can reach 801°F with nights plummeting to -279°F)

KNOWN MOONS
0

GRAVITY COMPARED TO EARTH
38%
(200-pound human would weigh 76 pounds)

NOTABLE FACT
Contrary to astrological beliefs, Mercury does not go ‘retrograde’. All planets appear to move backwards at times. A good analogy is how a car you pass on a highway seems to move in reverse but you are simply moving ahead of it. Also, rocks that are millions of miles away cannot affect your boss’s mood.

 

VENUS

NAMED FOR
The Roman goddess of love and beauty. (Greek equivalent is Aphrodite.)

AVERAGE DISTANCE FROM THE SUN
~ 67 million miles

ROTATION (SPIN) / REVOLUTION (ORBIT)
one Venusian day = 243 Earth days
one Venusian year = 225 Earth days
(yes, Venus’s day is longer than its year; it also spins in reverse!)

SIZE
7,520 miles across
(about 95% of Earth’s diameter)

AVERAGE SURFACE TEMPERATURE
880°F
(hot enough to melt lead)

KNOWN MOONS
0

GRAVITY COMPARED TO EARTH
91%
(200-pound human would weigh 182 pounds)

NOTABLE FACT
Venus’s very thick atmosphere creates a runaway greenhouse effect, rains sulfuric acid, and is composed mostly of carbon dioxide.

 

EARTH

NAMED FOR
A combination of Germanic and Old English words meaning ‘ground’. Earth was not originally considered a planet because people believed it was the center of the Universe, therefore it was not named for a god or goddess.

AVERAGE DISTANCE FROM THE SUN
~ 93 million miles

ROTATION (SPIN) / REVOLUTION (ORBIT)
one Earth day = 24 Earth hours
one Earth year = 365.25 Earth days

SIZE
7,917 miles across
(exactly 100% of Earth’s diameter)

AVERAGE SURFACE TEMPERATURE
61°F
(the highest ever recorded was 134°F in Death Valley, California, in 1913; the coldest was -128.5°F in Antarctica in 1983)

KNOWN MOONS
1 – The Moon
(kind of arrogant to call it that, no?)

GRAVITY COMPARED TO EARTH
One “G”, or 9.807 m/s²

NOTABLE FACT
Earth’s location in the Solar System, liquid water, and mild climate combine to make it the perfect place to support life as we know it.

THE MOON

DESCRIPTION
Earth’s only natural satellite is the largest moon in the Solar System, relative to its planet’s size. It does not create light but reflects it from the Sun (called albedo). Scientists think the Moon was created billions of years ago when an enormous asteroid crashed into Earth and the planet’s gravity captured a piece of broken rock.

AVERAGE DISTANCE FROM EARTH
238,855 miles

ROTATION (SPIN)
Earthlings see the same side of the Moon every night (about 59% of the total surface area) because it spins at the same speed it orbits, approximately 27 days. The “far side” of the Moon has only been seen in person by 24 astronauts during the Apollo missions of the late 60s and early 70s.

SIZE
2,158 miles across
(about 27% of Earth’s diameter)

AVERAGE SURFACE TEMPERATURE
Due to its thin atmosphere, the Moon can go from 240°F during the day down to -290 at night.

GRAVITY COMPARED TO EARTH
16.6%
(200-pound human would weigh 33.2 pounds)

NOTABLE FACT
Solar eclipses appear as they do because the Moon is about 400 times closer than the Sun and about 400 times smaller. This phenomenon makes it seem that the Moon nestles perfectly inside the Sun.

 

MARS

NAMED FOR
The Roman god of war. (Greek equivalent is Ares.)

AVERAGE DISTANCE FROM THE SUN
~ 142 million miles

ROTATION (SPIN) / REVOLUTION (ORBIT)
one Martian day = 24.6 Earth hours
one Martian year = 1.88 Earth years

SIZE
4,220 miles across
(about 53% of Earth’s diameter)

AVERAGE SURFACE TEMPERATURE
-20°F

KNOWN MOONS
2
(Phobos- Greek for fear, and Deimos- Greek for panic/terror)

GRAVITY COMPARED TO EARTH
38%
(200-pound human would weigh 76 pounds)

NOTABLE FACT
Mars appears red because of an abundance of iron-rich rocks, which oxidize (rust), spreading dust in the atmosphere, resulting in a pink-ish hue.

 

ASTEROID BELT

(mathematically predicted by German astronomer Johann Titius in 1766, then visually discovered in 1801 by Italian astronomer Giuseppe Piazzi)

DESCRIPTION
This “belt” contains billions of multi-sized objects made of rock and/or metal. They were likely of the same materials that formed planets but Jupiter’s intense gravity would not allow them to combine. The largest object in the belt is Ceres, a dwarf planet 590 miles in diameter. The Chicxulub asteroid that extinguished the dinosaurs probably came from the Asteroid Belt.

AVERAGE DISTANCE FROM THE SUN
~ 251 million miles

SIZE
The belt averages 92 million miles in thickness.
(despite the abundance of rocks, a spaceship traveling through has a one-in-a-billion chance of collision, due to the enormity of the area)

NOTABLE FACT
The word ‘asteroid’ comes from Greek and means star-like. They are clearly not stars (nor planets) but some have small moons and even volcanoes that erupt ice.

 

JUPITER

NAMED FOR
The Roman king of the gods. (Greek equivalent is Zeus.)

AVERAGE DISTANCE FROM THE SUN
~ 484 million miles

ROTATION (SPIN) / REVOLUTION (ORBIT)
one Jovian day = 9.8 Earth hours
one Jovian year = 11.86 Earth years

SIZE
86,881 miles across
(about 11 times_­ larger than Earth’s diameter)
(over 1,300 Earths could fit inside Jupiter)

AVERAGE SURFACE TEMPERATURE
-162°F
(though not known for certain, Jupiter’s core is estimated to be 24,000-43,000°F or even higher)

KNOWN MOONS
79
(the four largest are the “Galilean” moons- Callisto, Europa, Ganymede, and Io)

GRAVITY COMPARED TO EARTH
240%
(200-pound human would weigh 480 pounds)

NOTABLE FACT
Jupiter’s Great Red Spot is a storm which is bigger than Earth, with winds exceeding 400 miles per hour. First officially observed in 1831, it has been raging for at least a few hundred years.

 

SATURN

NAMED FOR
The Roman god of agriculture. (Greek equivalent is Cronus.)

AVERAGE DISTANCE FROM THE SUN
~ 886 million miles

ROTATION (SPIN) / REVOLUTION (ORBIT)
one Saturnian day = 10.2 Earth hours
one Saturnian year = 29.4 Earth years

SIZE
72,367 miles across
(about 9.1 times larger than Earth’s diameter)

AVERAGE SURFACE TEMPERATURE
-218°F

KNOWN MOONS
82
(including Titan, Enceladus, and Rhea)

GRAVITY COMPARED TO EARTH
108%
(200-pound human would weigh 216 pounds)

NOTABLE FACT
Saturn’s famous rings are made up of ice and rock particles- some the size of sand, others as big as houses. They are likely the remnants of asteroids, comets, and even shattered moons. A swimming pool-sized amount of the rings averages falling toward Saturn every thirty minutes, which could make them disappear completely in 100 million years.

 

URANUS

(first identified in 1781 _CE by British astronomer William Herschel)

NAMED FOR
The Greek personification of Heaven. (Roman equivalent is Caelus.)

AVERAGE DISTANCE FROM THE SUN
~ 1.8 billion miles

ROTATION (SPIN) / REVOLUTION (ORBIT)
one Uranian day = 17 Earth hours
one Uranian year = 84 Earth years

SIZE
31,518 miles across
(about 3.99 times larger than Earth’s diameter)

AVERAGE SURFACE TEMPERATURE
-320°F

KNOWN MOONS
27
(including Titania, Oberon, and Ariel)

GRAVITY COMPARED TO EARTH
89%
(200-pound human would weigh 178 pounds)

NOTABLE FACT
The tilt of Uranus’s axis is almost 98°, meaning the planet’s north pole is south of its center. Its exterior (see above) shows that the gas clouds are nearly perpendicular to the orbital plane, instead of parallel like the other giant planets. This tilt was likely caused by a collision with a huge (possibly Earth-sized) object.

NEPTUNE

(first identified in 1846 _CE by German astronomer Johann Gottfried Galle (with assistance))

NAMED FOR
The Roman god of the sea. (Greek equivalent is Poseidon.)

AVERAGE DISTANCE FROM THE SUN
~ 2.8 billion miles

ROTATION (SPIN) / REVOLUTION (ORBIT)
one Neptunian day = 16 Earth hours
one Neptunian year = 165 Earth years

SIZE
30,599 miles across
(about 3.86 times larger than Earth’s diameter)

AVERAGE SURFACE TEMPERATURE
-331°F

KNOWN MOONS
14
(including Triton, Naiad, and Proteus)

GRAVITY COMPARED TO EARTH
114%
(200-pound human would weigh 228 pounds)

NOTABLE FACT
Neptune has the strongest winds in the Solar System, which can exceed 1,200 miles per hour. This is likely due to the planet having its own internal heat source that counteracts with the cold temperatures outside. The short explanation of how scientists can measure weather on such a distant object has to do with analyzing gravity fields and monitoring cloud rotation.

PLUTO

(first identified in 1930 _CE by American astronomer Clyde Tombaugh)

NAMED FOR
The Roman god of the underworld. (Greek equivalent is Hades.)

AVERAGE DISTANCE FROM THE SUN
~ 3.7 billion miles

ROTATION (SPIN) / REVOLUTION (ORBIT)
one Plutonian day = 6.4 Earth days
one Plutonian year = 248 Earth years

SIZE
1,473 miles across
(about 19% of Earth’s diameter)

AVERAGE SURFACE TEMPERATURE
-388°F

KNOWN MOONS
5
(the largest is called Charon)

GRAVITY COMPARED TO EARTH
7%
(200-pound human would weigh 14 pounds and could jump VERY high)

NOTABLE FACT
Pluto’s orbit crosses Neptune’s, making it closer to the Sun for about 20 Earth years during its single Plutonian year. When I learned the order of the planets in the 1980s and ‘90s, Pluto was actually eighth in order. This is, of course, when Pluto was considered a planet…

WHY IS IT NO LONGER A PLANET?
In 2006, the International Astronomical Union set new guidelines on what defines a planet- 1) It orbits the Sun, 2) It has a round-ish shape, 3) It has cleared its orbital neighborhood. Pluto fits the first two criteria but shares orbital space with other Kuiper Belt objects (see below), making it almost-but-not-quite a planet.

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OTHER DWARF PLANETS

As defined above, a dwarf planet orbits the Sun, has a round-ish shape, and has not cleared it orbital neighborhood.

Aside from Pluto, the four officially-named dwarf planets are:

Ceres – Located in the Asteroid Belt, it has a diameter of approximately 590 miles and was the first asteroid to be discovered, though it has since been reclassified.

Eris – Located in the Kuiper Belt, it has a diameter of approximately 1,445 miles and an atmosphere that has been frozen.

Makemake – Located in the Kuiper Belt, it has a diameter of approximately 888 miles and was named for the Rapanui (Easter Island) god of creation.

Haumea – Located in the Kuiper Belt, it has a diameter of approximately 770 miles and an elongated shape due to its fast rotation.

 

KUIPER BELT

(Pluto was the first Kuiper Belt object to be discovered, though the belt itself was predicted in 1951 by Dutch astronomer Gerard Kuiper and visually observed by British and American astronomers David Jewitt and Jane Luu in 1992)

DESCRIPTION
Like the Asteroid Belt, the Kuiper Belt is an oblong ring of rock and ice orbiting the Sun. It is also the source of many comets, such as the famous Halley’s Comet. As Jupiter may have disrupted objects in the Asteroid Belt from forming a planet, Neptune may have done the same for the bodies in the Kuiper Belt.

AVERAGE DISTANCE FROM THE SUN
~ 4.65 billion miles

SIZE
The belt averages being 930 million miles thick but may be even wider.

NOTABLE FACT
A comet is like a cosmic snowball made of rock, dust, and frozen gas. The gravity of planets causes it to leave its “belt” orbit and form its own around the Sun. As a comet nears the Sun, the heat melts the gas, resulting in the “tail” seen in many common depictions.

 

OORT CLOUD

(This mysterious entity has never been visually observed due to its distance and lack of brightness. The idea of a gigantic, comet-producing realm at the edge of the Solar System was introduced by Estonian astronomer Ernst Öpik in 1932. His theory was clarified and updated by Dutch astronomer Jan Oort in 1950. The cloud’s existence is widely accepted in the scientific community.)

DESCRIPTION
The Oort Cloud contains a countless amount of icy planetesimals, which are pieces that could have formed planets but failed to do so. It is the primary source of ‘long-period comets’ that take at least 200 years to orbit the Sun.

AVERAGE DISTANCE FROM THE SUN
~ 2.3 trillion miles

SIZE
Its true size is not yet known but theories measure it in astronomical units (AU) because the distance is so vast. One AU is equal to the average distance between Earth and the Sun, about 93 million miles. If the Oort Cloud stretches somewhere between 2,000 and 50,000 AU, that would mean from 186 billion miles to 4.6 trillion miles, which is about ¾ the length of a light year.

NOTABLE FACT
The “cloud” is not a ring moving along the same plane as the other objects in this article but more of a sphere encasing the entire Solar System.

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The information in this article was thoroughly-researched but some may still be inaccurate due to conflicting scientific theories and the enormity of space. If you spot an error, please say so in the comments section below and I will investigate.

Meteors, meteoroids, and meteorites had no place in this article but their descriptions can be found on my What’s The Difference? page under the Science heading.

Thanks for reading!

 

SOURCES: Google, NASA, Scientific American, Museum of Applied Arts & Sciences, National Dairy Development Board, 1001 Things Everyone Should Know About The Universe (1997) by William A. Gutsch, Space.com, The Exploratorium, CalTech.edu, UniverseToday.com