solar system

Dyson Spheres: Smart or Stupid?

Astronomy and Physics, Earth, News

The other day my dad made a bold claim: Dyson spheres are stupid. I told him that they were not stupid, and he replied that they are because they’re physically impossible. 

I have to admit, he may have a point there. I mean, a true Dyson sphere would have to be quite large. That would take a lot of materials. Does the Earth have enough materials? Does the solar system? 

A Dyson sphere is a theoretical structure that encompasses a star. This structure would harvest as much sunlight as possible.

Olaf Stapledon made the first mention of Dyson spheres in his book Star Maker, but Freedman Dyson later proposed them in a scientific journal as a solution to an advanced civilization’s energy shortage. We rank hypothetical advanced civilizations on the Kardashev Scale, which is based on energy consumption. Currently, humans are not advanced enough to show up on the scale. However, a civilization with a Dyson sphere would be a Type II civilization—they would be able to harness the energy of their star. 

The sun is constantly producing 386 septillion watts of energy. Less than a billionth of a percent of this energy reaches the Earth. Humans harvest even less than this. Clearly, there is a ton of missed solar energy. 

But how would a Dyson sphere actually work? If it were to encompass the sun, but not the Earth, we would no longer receive sunlight. That wouldn’t work; it’s common knowledge that we need sunlight for life. So maybe it should follow the Earth’s orbit, with a little gap for the Earth. Or maybe it should be a little bigger than the Earth’s orbit and hold us inside too. Either way, that would be an astronomically large structure. The Earth is 93 million miles from the sun, so a sphere of that size would have a surface area of 109 quadrillion miles squared. My dad is right, that would be (nearly) impossible. There are not enough materials on the Earth. Luckily, there are enough materials in the solar system to build one. However, I wouldn’t count on it. 

An artist’s concept of a Dyson sphere. Source: CapnHack, via energyphysics.wikispaces.com

Okay, so we can’t have a Dyson sphere. But maybe we can have a Dyson part of a sphere? Or a Dyson fleet of satellites? Some (my dad), may argue that this is not a true Dyson sphere, but we could harvest far more energy than we do now. Right now, humans can only dream of a Dyson sphere. We don’t have the technology to build such a thing. Even a simpler version would be way out of our league. An array of satellites would need carefully calculated orbits. However, some of these orbits would probably overlap, thus blocking the very light they were sent to collect. 

While a Dyson sphere would be really cool, we don’t need to go to space to harvest light for energy. I mean, we have plenty of working solar panels on Earth. Plus, they’re becoming more popular; solar energy has been increasing for years and continues to do so. While solar energy isn’t as efficient at producing energy as fossil fuels are, you don’t have to pay for sunlight. 

Maybe Dyson spheres are in our future—not our near future, of course. I, for one, don’t have a lot of hope. I think they’re a cool theoretical structure, but I believe they will remain exactly that: theoretical. I would also like to say that my dad is not right. Dyson spheres are not dumb. We just have to be smart enough to build them.

July Sky Spotlight

Astronomy and Physics, Earth, News

2nd – New Moon, Total Solar Eclipse

July will start off as strong as June did! On only the second day of the month, we will have a total solar eclipse. Most of South America will be able to see at least a partial eclipse. Check Time and Date to see if you’re in the path!

3rd – Moon with Mars and Mercury

Astronomers call the sliver after a new moon a young moon. July’s young moon will be hanging out with Mars and Mercury in the constellation Cancer.

4th – Earth at Aphelion

The Earth’s orbit around the Sun is not a perfect circle, it’s an ellipse. This means that at some point, it must be at it’s furthest point from the Sun. That is in July! Aphelion is when a planet is farthest from it’s sun. This won’t affect our life at all, it’s just a neat fact.

9th – First Quarter, Saturn at Opposition

On July 9th, the Moon will be in it’s first quarter phase. This means that the left half will be dark and the right half will be light.

In addition, Saturn will be at opposition. This means that Earth will be directly between Saturn and the Sun.

13th – Moon with Jupiter

Jupiter and the Moon will be together in the constellation Scorpius in the Southern sky.

15th – Moon with Saturn

Saturn will be just East of the nearly full moon. They will be together in the constellation Sagittarius in the Southern Sky.

16th – Full Moon, Partial Lunar Eclipse

Most of the world (not including North America) will be able to see the Partial Lunar Eclipse! Check Time and Date to see if you’re in the path. If, like me, you are not in the path, enjoy the bright, beautiful full moon.

20th – Moon with Neptune

The Moon will be with Neptune in the constellation Aquarius in the Eastern night sky.

24th – Last Quarter, Moon and Uranus

On the 24th, the Moon will be in it’s last quarter with Uranus. They will be in Aries.

28th – Southern Delta Aquariid Meteor Shower Peaks

From midnight to dawn, and especially at 2 a.m., we will be able to see meteors originating from Aquarius. The moon will be a dark crescent, so the meteors will be easier to see. It is more visible from the Southern hemisphere than from the Northern Hemisphere.

31st – New Moon

Finally, on the last day of the month, we will end the same way we began: with a new moon.

Happy July viewing!

How to Send Your Name to the Red Planet

Astronomy and Physics, News, solar system

Almost every child has dreamed of being an astronaut. We look up at the stars and wonder what’s up there. While not everyone will be an astronaut, there are other ways to get your name to space.

NASA has announced a public engagement campaign in which anyone can submit their name to be sent to Mars. The names will be etched onto a chip and sent with NASA’s Mars 2020 rover. The names will be written “smaller than one-thousandth the width of a human hair”, according to NASA.

So far, over 4 million names have been submitted. A single chip can hold over a million names, but I think it’s safe to assume that NASA will be sending more than one chip with the rover.

Everyone who submits their name will receive a “boarding pass” for a flight to Mars. This boarding pass is, of course, for fun, and not a ticket to the Red Planet. It also “awards” frequent flyer points.

Anyone who wants to submit their name has until the end of September to do so. To submit your name, click here.

The rover will launch in July/August 2020 because Mars and the Earth will be close to each other. When they’re closer together, it takes less fuel, time, and money to launch. Therefore, these “close approaches” are simply the best time to launch.

Artist concept of the Mars 2020 rover. Source: NASA/JPL-CalTech

This rover’s main research will be regarding potential life on Mars. The rover will drill into the Martian surface to collect rock and dirt samples. These samples will be set aside, potentially to be brought to Earth in the future. In addition, the rover will look for organic compounds in the rocks. Other functions include testing an oxygen-production method and looking for subsurface water.

NASA’s Mars 2020 rover is going to allow us to understand the Red Planet’s history as well as we understand the Earth’s. In addition, scientists are hoping to answer questions about the possibilities of humans residing on Mars. That goal, however, is a long way away. NASA has recently announced plans to land humans on the Moon by 2024. This is a huge step towards Mars, but the Moon is considerably closer than Mars. Right now, the plan is to land humans on Mars in the 2030s.

Slowly but surely, humanity is going to Mars. It’ll be an exciting thing to watch. Click here for more information on Mars 2020.

Best Moons in our Solar System

Astronomy and Physics, solar system

In our solar system, there are nearly 200 moons orbiting eight different planets. Of course, these moons aren’t split evenly. Mercury and Venus don’t have any moons, while Jupiter has over 70—and counting. With this many moons, it’s easy to pick favorites. So I did! Here are six of my favorite moons in the solar system.

Our moon

Left: From Bill Ingalls. Top Right: Apollo 8’s iconic Earthrise, taken by Bill Anders. Bottom Right: The moon, as viewed from Earth, with Venus to the left. From Bill Dunford. Source: NASA

Naturally, I have to start with our moon, sometimes called Luna. Our Moon has a radius of 1080 miles (1737.5 kilometers) and is 238,855 miles (384,400 kilometers) from the Earth. With roughly the same apparent size as the Sun, the moon is the brightest object in our night sky. The Moon is tidally locked with the Earth, meaning we always see the same side of the Moon. The side we don’t see is often called “the dark side of the Moon,” but this is simply not true. This side of the Moon is lit by the Sun just as often as the other side.

The Moon is the only place outside of the Earth that humans have been. Thanks to this, we know tons about the Moon. For example, we know that the Moon has no atmosphere, and therefore, no wind. In addition, we have a pretty good map of the Moon and its craters. These craters are the most prominent features on the Moon’s surface.

Mimas

Left: Taken by the Cassini spacecraft. Top Right: Saturn with Mimas, a tiny dot to the bottom left of the image. Taken by the Cassini spacecraft. Bottom Right: Taken by Voyager 1. Source: NASA/JPL

Mimas just might be my favorite moon in the solar system. Discovered orbiting Saturn by William Herschel in 1789, it’s most prominent feature is the giant crater (complete with a central peak) on the right side of the image. This crater is named Herschel, after, of course, the man who discovered the moon. In the 1980s, NASA got its first up-close images of the moon as the Voyager crafts passed by. Immediately, many Star Wars fans noticed that Mimas looks an awful lot like the Death Star! Years later, the Cassini spacecraft took more fantastic images of the moon.

Mimas is one of Saturn’s closer moons, orbiting only 115,000 miles (186,000 kilometers) from the planet. Like our moon, Mimas is tidally locked with Saturn. Mimas is slightly ovoid (meaning a little more oval than a sphere, like an egg) and has a mean radius of 123 miles (198 kilometers). In addition, Mimas seems to be made entirely of water ice.

Io

Top Left: An eruption can be seen as a blue haze on top of the planet. Taken by the Galileo spacecraft. Bottom Left: A tiny Io is dwarfed by Jupiter. Right: Io, in true color. Source: NASA/JPL/University of Arizona

In 1610, Galileo pointed his telescope towards Jupiter and noticed four little dots moving back and forth across the planet. These four dots are now known as the Galilean Moons, my favorite of which is Io. Only a little larger than our moon, Io shoots around Jupiter in less than two Earth days at a distance of 262,000 miles (422,000 kilometers). As Io speeds around Jupiter and through its electric field, the moon generates a current that sparks lightning in the planet’s upper atmosphere.

Io’s weird, dotted color (making it look a little like a moldy pizza) is due to the volcanoes that cover the moon. In fact, Io is the most volcanically active body in the solar system. Like Mimas and our moon, Io is tidally locked with Jupiter. This, along with its highly elliptical orbit, cause insane tidal forces on the moon. These forces heat up Io, causing all the volcanic activity. Io seems to be made of mostly sulfur or silicate rock. These materials would explain Io’s “moldy pizza” appearance.

Phobos and Deimos

Top Left: Phobos. Bottom Left: Deimos. Right: Mars with the two moons as seen by Curiosity. Source: NASA/JPL-Caltech/GSFC/Univ. of Arizona

Deimos and Phobos were discovered by Asaph Hall in 1877. These cratered, irregularly shaped moons are among the smallest in the solar system. Right now, it’s believed that these moons are captured asteroids, but it’s possible that this is untrue. Like many other moons, these are tidally locked with Mars.

Phobos, the larger of the two, speeds around Mars three times a day. This moon is gradually moving closer to the planet, meaning that in the future, it will either crash into Mars or break apart into rings. A prominent feature of Phobos is the giant impact crater, called Stickney. Stickney is 6 miles (9.7 kilometers) wide.

Deimos only orbits Mars once every 30 hours. Deimos appears to be so tiny that it’s gravitational pull can’t hold onto ejected material after a meteorite strikes.

Titan

Left: The first image of Titan’s surface, taken by the ESA’s Huygens probe. Top Right: Titan and Diane (another of Saturn’s moons) in front of the Planet. Taken by Cassini. Bottom Right: Titan in front of Tethys (another of Saturn’s moons). Taken by Cassini. Source: NASA/JPL/ESA/University of Arizona

Titan has a radius of 1,600 miles (2,575 kilometers) and orbits Saturn once every 16 Earth days. Titan is Saturn’s largest moon, and the only moon known to have a significant atmosphere. This atmosphere, made of nitrogen, gives Titan it’s hazy appearance. Titan rains methane and ethane onto a water ice crust. Seas, lakes, and rivers, also made of methane and ethane, flow across the surface. Beneath the crust is a sea of water.

Titan’s water interior could hold life. Even more exciting, however, is the possibility of the surface holding life. Life that formed on Titan’s surface would be chemically different from our own. That being said, there is currently no evidence of Titan containing life; more research is needed.

Europa

Top Left: Taken by the Galileo spacecraft. Bottom Left: Europa’s scratched surface, taken by the Galileo spacecraft. Right: Jupiter with Europa to the right, casting a shadow on the planet. Source NASA/JPL-Caltech/SETI Institute/ASU

Europa, another Galilean moon, is largely considered to be the best shot at life off of Earth. Europa has a diameter of 1,940 miles (3,100 kilometers) and orbits Jupiter twice every seven Earth days. Europa’s surface is made of water ice with a deep liquid water ocean underneath. This icy surface is covered with scratches and cracks due to tidal forces from Jupiter, Io, and Ganymede. These tidal forces also heat up Europa’s subsurface sea.

Like Io, Europa also has an induced magnetic field from Jupiter’s magnetic field. The fact that there is a magnetic field suggests a salt water ocean under the icy surface. We know that life could potentially form there because life has formed in similar conditions on Earth. Right now, missions are being planned by NASA and the ESA (European Space Agency) to find life on Europa.

All the data in the article came from NASA.

The Plight of Pluto

Astronomy and Physics, solar system

Ah, Pluto. Everyone’s favorite (dwarf) planet. For some reason unbeknownst to the general public, scientists stripped Pluto of its planetary status in 2006. Many Millennials seem to feel personally attacked for this demotion. They dramatically claim that losing Pluto is like losing a member of our interplanetary family.

Unfortunately, scientists are right. Pluto is not a planet.

Discovering Pluto

In the 1840s, scientists noticed that Uranus’ orbit was inconsistent with predictions from the physics they knew of at that time. Using math, they concluded that another planet must be out there. Scientists pointed their telescopes to the sky and found Neptune. Even after finding Neptune, many felt that another planet must be out there because Neptune didn’t seem to solve all the problems with Uranus’ orbit. Since it had worked once before, they once again pointed their telescopes to the stars. And they found something.

The arrow points to a dot that moves separately from the background stars. This dot is Pluto. From the Lowell Observatory.

Scientists noticed something that was not a far away star—something close. Something orbiting the Sun. They assumed they had found a new planet because astronomers didn’t yet understand the structure of our solar system. They thought that Pluto was much larger and much farther away. However, as time went by, they calculated an increasing small mass for Pluto.

Eventually, astronomers realized the calculations that led to Pluto’s discovery were wrong. There were no problems with Uranus’ orbit. And even if there was, Pluto’s tiny mass wouldn’t account for this difference.

As time went by, astronomers found more Pluto-like objects in the outer solar system, including Eris. A dwarf planet discovered in 2003, Eris is more massive than Pluto (although a little smaller). This forced astronomers to re-evaluate their definition of a planet.

Defining a Planet

In 2006, scientists gathered at The International Astronomy Union’s General Assembly and tackled the question plaguing astronomy at the time: what defines a planet? They decided that a planet must do three things:

1. Orbit a star.

Pluto does this. Check.

2. Be massive enough to hold itself together in a round shape.

Pluto does this too. Check.

3. Dominate its neighborhood.

Pluto does NOT do this. Pluto lies in a portion of the solar system known as the Kuiper Belt, a region that contains small icy bodies, like a second asteroid belt.

Pluto’s orbit, seen in yellow, goes right through the Kuiper Belt. The planets’ orbits, which are white, each trace out their own area. Source: nasa.gov

To be fair, Pluto is a fairly large object for it part of the Solar System; it’s the second most massive non-planet orbiting the Sun. That being said, some moons are larger than Pluto. Looking at the image above, Pluto definitively does not dominate its neighborhood. Scientists ultimately demoted Pluto (and Eris) to a “dwarf planet.”

More evidence

Tilt with the ecliptic

All eight of our planets lie within the same plane of the solar system called the ecliptic plane. However, Pluto is 17 degrees off of this plane. The only other planet to be off the ecliptic is Mercury, but this difference is easily explained by General Relativity. So the question remains: how did Pluto get off the ecliptic?

Pluto’s orbit is vary different from the others. Source: nasa.gov

One theory is that Pluto may have collided with another object, knocking it out of the plane. Another theory is that Pluto may be a captured satellite from a different solar system. Either way, this orbital tilt is very weird for a planet, but quite normal for a Kuiper Belt object.

Charon and Pluto

Another damning piece of evidence comes from Pluto’s moon, Charon. Charon’s mass is about one-eighth of Pluto’s mass, which is relatively large for a moon. For comparison, our moon is only 1.2 percent of the Earth’s mass. This giant moon doesn’t actually orbit Pluto; instead, Pluto and Charon orbit a spot in between them, outside of either body.

Charon, on the left, is quite large for a moon. Pluto, on the right, is the object that Charon Orbits. Taken by the New Horizons Spacecraft. Source: nasa.gov

Some feel that Charon and Pluto should be considered a binary system. However, Charon’s official classification is one of Pluto’s Satellites.

It is important to note that Pluto’s moons don’t make it a planet. 87 Pluto-like objects are also known to have moons. Also, not all planets have moons; Mercury and Venus don’t.

Sorry folks, Pluto is not a planet

When you look at all the evidence, it’s clear that Pluto isn’t a planet. Pluto was only considered a planet because we didn’t know what our solar system looked like. Once we learned more, we needed to reclassify certain objects. That’s what science is all about—learning and adapting.

Pluto didn’t change, it’s official classification did. This, of course, doesn’t mean that we should forget about Pluto. There is still much Pluto can tell us about our solar system; that’s why scientists continue to study the dwarf planet. However, to say that Pluto is as important in the solar system as the planets is completely false. Regardless of what we call it, Pluto is undoubtedly one of the most loved objects in the solar system.

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