For today, I wanted to share a few pages from my book that highlight some of the many wonders of our universe:
Look up at the stars and not down at your feet.
Try to make sense of what you see and wonder
about what makes the universe exist. Be curious.
– Stephen Hawking
Consider that at this very moment, you are standing on a rock that is spinning on its axis at approximately 1,000 miles per hour, hurtling through space at 67,000 miles per hour, while it orbits a star. Yet, you can’t feel a thing.
Or how about this: Gravity—that universal action that grounds all life on our planet and holds other worlds and their moons in orbit—remains a mystery as to what it is and how it works.
And what the heck is ball lightning? How does a glowing and crackling ball of light appear and disappear at will, possess the ability to move through solid objects, and seem to float with abandon in fields, airplanes, and even our homes and workplaces during thunderstorms?
The forces and events that shape our planet and universe have inspired artists, poets, and scientists for centuries. Some forces on Earth such as volcanoes, earthquakes, tornadoes, and hurricanes can be terrifying and destructive. Others, such as rainbows, first snowfalls, and sunsets, bring joy and inspire romanticism in us all. Yet, they all can take our breath away with their overwhelming beauty or raw power.
Take a moment and ponder just a few of our galactic wonders.
The Sun
Size Matters: The Sun is massive, accounting for 99.86% of the total mass of our solar system. To put it into perspective, you could fit 1.3 million Earths inside the Sun. The Sun’s incredible mass creates a gravitational pull that keeps Earth and all the other planets in our solar system in orbit. The gravitational pull it creates is about 28 times stronger than that of Earth.
Giant Ball of Gas: The Sun is a massive ball of hot, glowing gas composed primarily of hydrogen (about74%) and helium (about 24%).
Powerhouse of Energy: The Sun generates an astonishing amount of energy through nuclear fusion. It releases the equivalent of 100 billion atomic bombs every second.
A Symphony of Sound Waves: The Sun produces powerful waves of sound due to the pressure gradients created from nuclear plasma present in its atmosphere. But because space is a vacuum, we can’t hear them unless we use specialized instruments. How loud would the sun’s sound waves be if we could hear them? Think 100 decibels loud. That would be equivalent to standing next to a never-ending freight train, rock concert speaker, or jackhammer. Earmuffs anyone?
Travelling Through Space: The Sun may be massive, but it can move fast. In fact, it is in constant motion, spinning at 4,470 miles per hour as it orbits the Milky Way Galaxy once every 225 to 250 million years.
All Shook up: Like earthquakes on Earth, the Sun experiences “sunquakes” caused by large solar flares that cool, condense, and reenter the Sun’s gravitational surface. These sunquakes produce vibrations that help scientists understand the Sun’s internal dynamics. Sunquakes are measured using the Helioseismic Magnetic Imager (HMI), which is not the same way we measure earthquakes on Earth. However, it has been estimated that even a small sunquake would be equivalent to a level 12 or 13 earthquake on Earth—an event that would likely cause planetary instability. Fortunately, this is an impossibility, as Earth does not have a fault line long enough to produce an earthquake of this magnitude.
Light Travel: It takes about 8 minutes and 20 seconds for light to travel from the Sun to Earth. This means that the sunlight we see is already 8 minutes old.
Turn, Turn, Turn: The Sun does not rotate uniformly. Its equator rotates at 4,470 miles per hour at its surface, whereas its poles rotate at 2,800 miles per hour. This unique rotation is referred to as “differential rotation” and is believed to be due to the Sun’s gaseous nature.
What’s in a Year? It takes Earth 365 days to make a complete orbit around the sun. This orbit together with Earth’s tilt are responsible for the four seasons.
The Moon
Not as Big as It Looks: The Moon has a diameter of 2,160 miles. That’s 27% the diameter of Earth. In fact, Australia is wider than the Moon is.
A Familiar Face: The Moon rotates on its axis just like Earth does. However, because the moon rotates in perfect synchrony with Earth’s orbit and takes only 29 days to complete one orbit around the Earth, we see only one face of the Moon. This phenomenon is referred to as “tidal locking.”
Making Waves: Speaking of tides, the Moon affects Earth’s oceans by creating regular ocean tide changes. These tides result from the gravitational pull the Moon creates as it orbits Earth.
Hold Your Breath: The Moon doesn’t have an atmosphere like Earth does, which means there’s no weather, wind, or erosion on its surface. That’s why the footprints of astronauts from the Apollo missions are still visible on the Moon’s surface.
A Weighty Matter: Need to lose a few pounds? Head to the Moon. The gravity on the Moon is about one-sixth that on Earth. This is why astronauts on the Moon appear to move so gracefully and can jump much higher. Put another way, an individual who weighs 120 pounds on Earth would “weigh” only 20 pounds on the Moon.
Our Solar System and The Milky Way Galaxy
A Memorable Mnemonic: Our solar system has eight planets. In order from the Sun, they are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. An easy way to remember this order is by the mnemonic, “My very excellent mom just served us noodles.” Pluto used to be considered the ninth planet in our solar system but was demoted to the status of dwarf planet in 2006 by the International Astronomical Union (IAU) amid heated debate.
Tighten Your Belt: Between the orbits of Mars and Jupiter lies the asteroid belt, composed primarily of rocky debris and asteroids. It is where most asteroids in our solar system are found. Beyond the orbit of Neptune lies the Kuiper Belt, a region of icy bodies, comets, and dwarf planets. It is like the Mars-Jupiter asteroid belt but much larger and further from the Sun.
Out-of-This-World Terminology: “Asteroids” are often referred to as minor planets or “planetoids.” They are rocky bodies varying in size from small boulders to ones hundreds of miles in diameter. “Meteoroids” have similar composition to asteroids but are smaller. “Comets” are composed primarily of ice, dust, and rocky material and release gas as they orbit the Sun. A “meteor” is what we see when a meteoroid ignites on contact with Earth’s atmosphere and streaks across the sky in a ball of light. A “meteorite” is a fragment of a meteoroid that hits the ground on Earth’s surface.
Dirty Snowballs: Comets are often referred to as “dirty snowballs,” as they are composed primarily of ice, dust, and rocky material. When they approach, the Sun’s heat causes the ice to vaporize, creating a glowing comet and tails. Halley’s Comet, a well-known comet to most people, has been observed for centuries and appears roughly every 76 years. It was last visible from Earth in 1986 and will next be visible in 2061.
Spilled Milk: Earth lies within the Milky Way Galaxy. The term, “Milky Way,” comes from its appearance as a milky band of light stretching across the night sky. In ancient times, it was often likened to spilled milk or a pathway in the heavens. The Milky Way is 100,000 light years in diameter and contains hundreds of billions of stars.
Galactic Cannibalism: The Milky Way has encountered and consumed smaller galaxies throughout its history. Evidence of past mergers and acquisitions can be seen in streams of stars and globular clusters orbiting the galaxy.
Galactic Collision: In about 4 billion years, the Milky Way is expected to collide with the neighboring Andromeda Galaxy, leading to a merger that will form a single, larger galaxy dubbed “Milkomeda” or “Milkdromeda.”
Unimaginable Size: The observable universe reaches out 93 billion light years from Earth and is 13.8 billion years old. This vast expanse contains billions of galaxies, each with billions of stars. The shape of the universe remains a matter of debate among cosmologists.
Space
Space 101: Next time you watch your favorite space sci-fi movie, consider the following: space is dark—very dark. You will be able to see some light and stars, depending on your position, but as you look in a direction away from the Sun, there is little to reflect light to your eyes. Next, space is a vacuum; therefore, there is no medium (for example, air) by which sound can travel. You will not hear a thing when the Death Star or the Klingon moon of Praxis explodes. Finally, space is very cold and offers no protection against cosmic radiation. So, what happens if your spacesuit has a hole in it? Well, you have about 15 seconds to get back to your ship. After that, you would lose consciousness due to the lack of oxygen to your brain. Despite popular myth, you would not explode, and your blood would not boil. But the nitrogen in your blood would create multiple emboli that would cause swelling, blockage, and hemorrhage of your tissues and internal organs. In addition to all this, due to the cold temperature and high radiation of space, you would experience severe hypothermia, flash-frozen skin, and a very nasty sunburn. Safety advisory for your next spacewalk? Make sure to check your spacesuit.
Tomorrow: I’ll share a few more excerpts from the book about more earthly wonders, like: What the heck is ball lightning? How does gravity work? And, why can it rain frogs?
Have a great day.
Pam
