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24 Astronomy Facts You Never Learned in School

From a bar in the clouds to finding more water from the Moon, outer space is constantly surprising us.

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the sun experiencing solar flares
Courtesy NASA

The sun is bigger than you can even imagine

When you look up at the sky and see the sun beaming down at you, it’s hard to tell how truly big it is. So consider this: About a million duplicates of Earth could comfortably fit inside of it, according to NASA. And if the sun didn’t supply our main energy, we’d be shivering in the dark; its core releases energy that is the equivalent of 100 billion nuclear bombs. Find out if the distance between the Earth to the sun is always the same.

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A Neptune-size planet with a clear atmosphere is shown crossing in front of its star in this artist depiction. Such crossings, or transits, are observed by telescopes like NASA Hubble and Spitzer to glean information about planets atmospheres.
Courtesy NASA

Hot ice is a thing

About 33 light-years away is an exoplanet called Gliese 436 b. The planet is composed of different water elements, which form burning ice. In other words, the ice on the planet remains solid due to pressure, while the extreme surface temperature of 570° F (300° C) super-heats the water, causing it to come off as steam. Imagine putting ice in your coffee to heat it up! These are the most amazing space discoveries of the past decade.

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W44 is located around 10,000 light-years away, within a forest of dense star-forming clouds in the constellation of Aquila, the Eagle. This image combines data from ESA Herschel and XXM-Newton space observatories.
Courtesy NASA

There’s a bar in the sky

It may seem like a bartender’s dream (or nightmare), but way up beyond our atmosphere, there’s a gas cloud made from alcohol about 1,000 times the diameter of our entire solar system. There’s enough alcohol there for about 400 septillion pints of beer (that’s 400 followed by 24 zeros!). To put that into perspective, that’s enough alcohol to supply 300,000 pints of beer to everyone on Earth daily for a billion years. Cheers! These amazing virtual space exhibits will make you feel like you’ve left our planet.

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Expedition 35 Flight Engineers Chris Cassidy (pictured) and Tom Marshburn (out of frame) completed a space walk at 2:14 p.m. EDT May 11 to inspect and replace a pump controller box on the International Space Station?s far port truss (P6) leaking ammonia coolant. The two NASA astronauts began the 5-hour, 30-minute space walk at 8:44 a.m.
Shutterstock (2)

Walking in space might cause you to crave a steak

Astronauts returning from a space walk have noted the aroma of various odors on their space suits ranging from metal to a charcoal-broiled steak. That’s due to polycyclic aromatic hydrocarbons (PAHs), which are by-products of dying stars. PAHs are also released from burning coal, wood, gasoline, and—you guessed it—charcoal-broiled meat. Learn more about what outer space actually smells like.

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This artist concept illustrates an asteroid belt around the bright star Vega. Evidence for this warm ring of debris was found using NASA Spitzer Space Telescope, and the European Space Agency Herschel Space Observatory.
Courtesy NASA

There’s a lot of trash out there

There may be a lot of garbage filling up our landfills on Earth, but there are over a million pieces of trash orbiting the earth, too. Space junk is a real problem and even something as small as a paper clip could wreak havoc on our satellite system—that could mean no Netflix for you, among more serious issues like messing with our national security system. Currently, there’s no great way to clean up space, but scientists are focusing on solutions.

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Astronaut Michael E. Lopez-Alegria, Expedition 14 commander and NASA space station science officer, drinks a beverage in the Zvezda Service Module of the International Space Station.
Courtesy NASA

Raspberries and rum in space

OK, you can’t actually go raspberry picking in space—yet. But, as it turns out, the main component that gives raspberries their distinctive flavor, ethyl formate, was discovered in the Milky Way in 2009. Ethyl formate is also a component of rum, but it’s also unlikely you’ll be able to order a rum and coke in the galaxy any time soon—especially since alcohol is one of the foods that are banned from space.

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This is an image of the planet Uranus taken by the spacecraft Voyager 2 in 1986.
Courtesy NASA

Uranus is quirky

As the only planet that rotates on its side, Uranus has scientists baffled. Some theories include that the planet’s orientation may have been altered at some point by a titanic collision with an asteroid or another planet. Either way, it’s the solar system oddball when it comes to planet rotations. But then, space is weird. These are the normal things astronauts can’t do in space.

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This NASA Hubble Space Telescope image, taken in near-infrared light, transforms the pillars into eerie, wispy silhouettes, which are seen against a background of myriad stars. The near-infrared light can penetrate much of the gas and dust, revealing stars behind the nebula as well as hidden away inside the pillars. Some of the gas and dust clouds are so dense that even the near-infrared light cannot penetrate them. New stars embedded in the tops of the pillars, however, are apparent as bright sources that are unseen in the visible image. The ghostly bluish haze around the dense edges of the pillars is material getting heated up by the intense ultraviolet radiation from a cluster of young, massive stars and evaporating away into space. The stellar grouping is above the pillars and cannot be seen in the image. At the top edge of the left-hand pillar, a gaseous fragment has been heated up and is flying away from the structure, underscoring the violent nature of star-forming regions. Astronomers used filters that isolate the light from newly formed stars, which are invisible in the visible-light image. At these wavelengths, astronomers are seeing through the pillars and even through the back wall of the nebula cavity and can see the next generations of stars just as they're starting to emerge from their formative nursery.
Courtesy NASA

Stargazing is (almost) like looking into the past

Since stars are so far away and their light takes so long to reach Earth, it’s possible the star you’re looking at is already dead. A good example is the Pillars of Creation, which are part of a region called the Eagle Nebula that’s 7000 light-years away from us. These pillar-like clouds of dust and gas were first imaged by the Hubble Telescope in 1995—but they were actually destroyed at least 6000 years ago by a supernova. What we’re seeing in Hubble’s 1995 image is what the Pillars of Creation looked like 7000 years ago. The good news: those “already dead” stars are rare, so the majority of the stars in the sky are still intact, and will be for a few more billion years. We can see a lot of space from Earth, but these are the things that you can see on Earth from space.

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This processed color image of Jupiter was produced in 1990 by the U.S. Geological Survey from a Voyager image captured in 1979. Zones of light-colored, ascending clouds alternate with bands of dark, descending clouds.
Courtesy NASA

Lose weight by planet hopping

If you’re, say, 140 pounds, did you know you would be about 53 pounds on Mercury? Without getting caught up in complicated math, the reason behind the swift weight change is the planet’s gravitational field. This is because your mass is constant across the universe, while your weight measurement changes depending on the force of gravity wherever you are—and gravity changes from planet to planet. Since Mercury’s gravitational field is less than Earth’s, you’d weigh less. If the gravitational field is more than the Earth’s, you’d, of course, weigh more. (Word to the wise: Avoid Jupiter, because it triples your weight!) These are the most baffling mysteries about the universe.

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Rocks: Windows to History of Mars
Courtesy NASA

Move over, moon rocks

You don’t have to go all the ways to Mars to get a souvenir from space. When meteorites were tested on Earth from the Sahara Desert and Antarctica, it was revealed that some rocks come from Mars.

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Four images from New Horizons Long Range Reconnaissance Imager LORRI were combined with color data from the spacecraft Ralph instrument to create this enhanced color global view of Pluto.
Courtesy NASA

Poor Pluto

Pluto was unceremoniously kicked off the team of full-sized planets we consider part of our solar system. (The rest of them are, of course, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.) “The International Astronomical Union reclassified poor Pluto as a dwarf planet in 2006—a move that had astrologers and many a stargazer alike upset at the demotion. Pluto lost its status due to being just half the width of the United States—way smaller than any of the other planets sharing the same status in the solar system. Calling Pluto a planet is just one of many facts you learned in school that are no longer true.

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View (part of a time lapse sequence) of stars in the Milky Way Galaxy visible over an Earth limb as seen by the Expedition 44 crew. Astronaut Kjell Lindgren captured a lightning strike from space so bright that it lights up the space station’s solar panels. He posted this on Twitter and Instagram on Sept. 2 saying "Large lightning strike on Earth lights up or solar panels."
Courtesy NASA

A long trip

The last time our solar system was in its current position around the Milky Way, the earliest dinosaurs were first roaming the Earth. That’s because it takes a whopping 230 million years for our solar system to complete one single orbit around the Milky Way. That really puts that long-day feeling into perspective.

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This color image of the Earth was obtained by NASA's Galileo at about 6:10 a.m. Pacific Standard Time on Dec. 11, 1990, when the spacecraft was about 1.3 million miles from the planet during the first of two Earth flybys on its way to Jupiter. The color composite used images taken through the red, green and violet filters. South America is near the center of the picture, and the white, sunlit continent of Antarctica is below. Picturesque weather fronts are visible in the South Atlantic, lower right. This is the first frame of the Galileo Earth spin movie, a 500- frame time-lapse motion picture showing a 25-hour period of Earth's rotation and atmospheric dynamics.
Courtesy NASA

Earth is slowing down

In the days of the dinosaur, a day was only 23 hours long. That’s due to the slowing of the Earth’s rotation each century by roughly two milliseconds. In 1820, the Earth’s rotation was 24 hours on the dot, notes NASA. Now, the Earth’s rotation is off by 2.5 milliseconds. We can’t blame our poor old Earth—we all slow down a bit as we age. We’ll take it if it means two more seconds of daylight in winter.

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full moon and the sun in the same photographic frame

Optical illusion

The sun and moon may look fairly similar in size when you look at the sky, but don’t let your eyes fool you. Not only does the sun actually dwarf the moon in size—it’s 400 times larger—it’s also 400 times further away from Earth than the moon. That distance gives the sun the illusion of appearing moon-size. We know why this is, but scientists are still working out these unanswered questions about the moon.

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The Moon during the day in the nature between trees
Michael Rosolia/Shutterstock

Daytime moon sighting

Depending on the moon’s position above the horizon and how it coincides with the sun’s position, you should be able to see the moon during the daytime. In fact, it’s actually pretty common—the only time you wouldn’t be able to see the moon is when it’s a “new” moon, meaning the lit side of the moon is facing away from the Earth.

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This image is an unannotated version of NASA Planetary Photojournal Home Page graphic. This digital collage contains a highly stylized rendition of our solar system and points beyond.
Courtesy NASA

Solar system maps are wrong

If a map of the solar system was created to scale, it would be way too big to hang. Using a single pixel to represent the moon, designer and developer Josh Worth created what he calls “a tediously accurate scale model of the solar system.” You’re probably better off going with the textbook version that makes the planets appear a wee bit closer if you want something to hang on your wall. Now that you know the truth about solar system maps, find out 18 other science facts you weren’t taught in school.

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The Polaris star and night sky with trees skyline.
Chameleons Eye/Shutterstock

Bye-bye, Polaris

Polaris, our North Star, isn’t leaving us anytime soon—at least not for another 12,000 years. But when it does, the star Vega will replace it. Why? It’s all about the rotation of the Earth. As our planet’s axis changes over a very long 26,000-year cycle, the north eventually shifts to different stars. It won’t be the first time Vega gets the starring role in our night sky; it was the North Star several thousand years ago.

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This image, taken with the Wide Field Planetary Camera 2 on board the NASA/ESA Hubble Space Telescope, shows the globular cluster Terzan 1. Lying around 20,000 light-years from us in the constellation of Scorpius (The Scorpion), it is one of about 150 globular clusters belonging to our galaxy, the Milky Way. Typical globular clusters are collections of around a hundred thousand stars, held together by their mutual gravitational attraction in a spherical shape a few hundred light-years across. It is thought that every galaxy has a population of globular clusters. Some, like the Milky Way, have a few hundred, while giant elliptical galaxies can have several thousand. They contain some of the oldest stars in a galaxy, hence the reddish colors of the stars in this image — the bright blue ones are foreground stars, not part of the cluster. The ages of the stars in the globular cluster tell us that they were formed during the early stages of galaxy formation! Studying them can also help us to understand how galaxies formed. Terzan 1, like many globular clusters, is a source of X-rays. It is likely that these X-rays come from binary star systems that contain a dense neutron star and a normal star. The neutron star drags material from the companion star, causing a burst of X-ray emission. The system then enters a quiescent phase in which the neutron star cools, giving off X-ray emission with different characteristics, before enough material from the companion builds up to trigger another outburst.
Courtesy NASA

Peace and quiet are out of this world

If you need some time to chill out and ditch all the noise on Earth, you might want to go for a spacewalk. That’s because we typically can’t hear sound in space. Sound travels by making molecules vibrate, but in space, there are only five protons in the same volume (a square centimeter of air) that you would find nearly 300,000,000,000,000,000,000 molecules in here on Earth. You would need “an eardrum comparable to the size of Earth” to hear the small pressure variations of the magnetosonic waves that you’d find in space. Don’t miss these science mysteries no one has figured out.

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Best-Ever Snapshot of a Black Hole's Jets
Courtesy NASA

Black holes belch stars

A black hole can actually suck up a star and burp it back out. Sound gross? When a star gets sucked up into a black hole, it will release a huge jet of plasma. This “burp” can span hundreds of light-years. “When the star is ripped apart by the gravitational forces of the black hole, some part of the star’s remains falls into the black hole, while the rest is ejected at high speeds,” notes Suvi Gezari, a researcher at Johns Hopkins University, to sciencealert.com.

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Pathfinder on Mars
Courtesy NASA

Mars is a bit rusty

Although there isn’t any water on Mars, it’s rusty red on its surface and so is its sky. Earth rust is made from iron and water, and one theory about the iron oxide on Mars is that it probably formed many eons ago, when there may have been water on the planet (there’s still ice at its north and south polar caps, just like on Earth). The planet remains very rich in iron oxide.

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View of Canadian Space Agency (CSA) Chris Hadfield,Expedition 34 Flight Engineer (FE),watching a water bubble float freely,showing his image refracted,in the Node 1. Photo was taken during Expedition 34.
Courtesy NASA

Even your tears won’t fall

Whether it’s tears or plain old water, the weightless atmosphere in space causes liquid to adhere to a surface rather than fall. When it comes to tears, they’ll just form bubbles around your eyes, so you’ll look like an alien. Fitting!

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Astronaut Pam Melroy, STS-120 commander, floats in the Orbiter Docking Compartment (ODS) after hatch opening between the International Space Station and Space Shuttle Discovery.
Courtesy NASA

Keep those socks on in space

Astronauts don’t spend a lot of time on their feet while they’re floating around in the weightless environment of space. This might give their tootsies a nice break, but it also causes the skin on their feet to soften and flake. Astronauts don’t change their underwear and socks frequently as they can’t do loads of laundry like at home. So watch out when they do—the sloughed-off skin can be released with each sock and end up floating about. Gross. Learn some more unbelievable but true facts about space travel.

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The northern hemisphere is displayed in this global view of the surface of Venus as seen by NASA Magellan spacecraft.
Courtesy NASA

Venus runs hot and cold

A planet with a reputation for an atmosphere five times hotter than boiling water, Venus has a cold spot, too. Although the average temp is hot, hot, hot, there’s a cold layer hidden in its atmosphere with temperatures of -175 °C and possibly carbon dioxide ice. “The cold layer is unique, in that Earth and Mars don’t have anything like it,” said Håkan Svedhem, ESA’s Venus Express project scientist, in a press release.

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Waning gibbous. Rises after sunset, high in the sky after midnight, visible to the southwest after sunrise. This marks the first time that accurate shadows at this level of detail are possible in such a computer simulation. The shadows are based on the global elevation map being developed from measurements by the Lunar Orbiter Laser Altimeter (LOLA) aboard the Lunar Reconnaissance Orbiter (LRO). LOLA has already taken more than 10 times as many elevation measurements as all previous missions combined. The Moon always keeps the same face to us, but not exactly the same face. Because of the tilt and shape of its orbit, we see the Moon from slightly different angles over the course of a month. When a month is compressed into 12 seconds, as it is in this animation, our changing view of the Moon makes it look like it's wobbling. This wobble is called libration. The word comes from the Latin for "balance scale" (as does the name of the zodiac constellation Libra) and refers to the way such a scale tips up and down on alternating sides. The sub-Earth point gives the amount of libration in longitude and latitude. The sub-Earth point is also the apparent center of the Moon's disk and the location on the Moon where the Earth is directly overhead. The Moon is subject to other motions as well. It appears to roll back and forth around the sub-Earth point. The roll angle is given by the position angle of the axis, which is the angle of the Moon's north pole relative to celestial north. The Moon also approaches and recedes from us, appearing to grow and shrink. The two extremes, called perigee (near) and apogee (far), differ by more than 10%. The most noticed monthly variation in the Moon's appearance is the cycle of phases, caused by the changing angle of the Sun as the Moon orbits the Earth. The cycle begins with the waxing (growing) crescent Moon visible in the west just after sunset. By first quarter, the Moon is high in the sky at sunset and sets around midnight. The full Moon rises at sunset and is high in the sky at midnight. The third quarter Moon is often surprisingly conspicuous in the daylit western sky long after sunrise. Celestial north is up in these images, corresponding to the view from the northern hemisphere. The descriptions of the print resolution stills also assume a northern hemisphere orientation. To adjust for southern hemisphere views, rotate the images 180 degrees, and substitute "north" for "south" in the descriptions.
Courtesy NASA

Moon water might one day be a thing

A study has found that the moon might one day be a space resource for water, as it contains a lot more H2O than previously thought. Scientists conclude we could extract water from pyroclastic deposits, a substance on the moon made mostly of volcanic glass beads formed during ancient explosive eruptions. Now that you know all these astronomy facts, see how you fare with these science trivia questions everyone gets wrong.