NASA has always been about accomplishing crazy. In the 1960s, the idea of people walking around on the moon was ludicrous, but NASA got them there anyways. Now, NASA is performing another crazy feat: sending a probe to an asteroid, collecting rock samples, and returning that probe to Earth. Additionally, the probe has created a digital map of the asteroid which we can recreate, simply by using a 3D printer.
In September 2016, the Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer space probe (OSIRIS-REx for short) was launched aboard an Atlas V rocket. It quickly made its way into space and began its journey towards the asteroid designated 101955 Bennu. This journey lasted over two years as the robe used low-power thrusters and gravity assists from Earth to reach its destination.
Side by Side – 3D Printing Asteroid
OSIRIS-REx reached Bennu in December of 2018, and as it approached, it used its long-range PolyCam sensors to map out the surface of the asteroid. After arriving, OSIRIS-REx used its short-range cameras to take even higher resolution images of Bennu’s surface. NASA scientists used that data to create 3D models and released them to the public!
A common misconception we see at AstroCamp is how gravity and atmospheric pressure work. It makes sense! The two seem interchangeable at a glance, however they both get weaker as altitude increases, and there can’t even be an atmosphere without gravity. Despite their similarities, the two are very different.
Gravity is a property of anything with mass. It’s one of the four fundamental forces in the universe, and it’s caused by an object bending spacetime around itself. The larger the object, the greater a force it will exert.
Pressure isn’t even a force (technically). It’s a measurement of how much force is being applied per unit area. A lot of force can be spread out over a large surface area so that the pressure is overall small, and a small force can be focused onto a small enough point to cause a high pressure.
When talking about atmospheric pressure, we’re talking about the average force per unit area the gas molecules are exerting on objects in the air. The air molecules are zooming everywhere and bouncing into everything. Every time they impact, they push with a tiny force.
Atmospheric pressure changes with 1) the rate of collisions and 2) the force of impact. More molecules mean more collisions, which leads to a higher air pressure. Similarly, heavier gases or gases moving at higher speeds will cause a higher impact force, also increasing the atmospheric pressure.
Air at sea level is being compressed by all of the air above it, weighing it down and increasing its density. When you increase altitude, the less air you have above you, so pressure goes down. This is why atmospheric pressure gets weaker the higher in altitude you go.
After learning how they both work, it’s easy to see why the effects of gravity and atmospheric pressure can get confused. But their differences are also prevalent enough that you should be able distinguish between the two!
A homopolar motor is a device that relies on flowing electricity, magnetic fields, and the interaction between the two. It consists of a voltage source, neodymium magnets, and a conductor that allows electricity to flow. And it’s super easy to make yourself!
What you’ll need:
1 AA battery
2 neodymium magnets
Thick copper wire
Place one of your magnets onto the positive terminal of the battery.
Use the already attached magnet to test the poles of the second magnet. Figure out which sides are repelling each other, and place the second magnet so that the repelling side faces away from the battery. This way, either both South poles or both North poles are facing outwards! (Note: it doesn’t matter which, as long as they’re consistent with each other!)
Shape your copper wire so that it can hook easily on the inside of the magnets. Try to maximize the amount of contact it has with the magnets on BOTH sides, so as much electricity as possible can flow. When it’s been properly shaped, hook the wire onto the motor!
Instead of using a wire, you could use a sheet of aluminum foil! Lay it as flat as you can on a level surface, away from any metals that might attract your magnets. Make sure there are no tears or holes in the aluminum. Then place your battery-magnet motor on top! The aluminum will allow electricity to flow!
When a magnetic field is applied to an object carrying electricity, it applies a force to that object. This is called the Lorentz Force. Due to the electricity flowing through the magnets, this force becomes a torque, causing the motor to rotate and drive forward!
Escape Velocity is probably something you’ve heard on a TV show, or maybe you learned about it from NASA talking about their newest spacecraft. It is a commonly discussed term, but it isn’t the easiest thing to understand. Imagine you’re in a strange universe where only the Earth exists. The only gravity comes from its center, and it extends infinitely far away, getting weaker and weaker the further away you get. In order to get to that infinite point before you get pulled back by the Earth’s gravity, you need to be going at least 11.2 km/s (25,000 mph). This speed is the escape velocity!
This value depends on both the distance from the gravitational center of the object you’re escaping from and the mass of the object. The closer you are to a heavier object, the faster you need to go to reach escape velocity. For example, escape velocity from the Earth at a distance of the moon’s orbit is only 1.3 km/s (3,000 mph), but to escape from the sun’s gravity at the distance of the Earth is a whopping 44.7 km/s (100,000 mph)!
But since there’s no such thing as a universe where only the Earth exists, we have to worry about the gravity of other celestial objects! Once you escape from the Earth’s gravity, you’ll then be captured by the sun. If you escape that, then you’ll be captured by the Milky Way’s gravity! So the hypothetical infinite point is just that: hypothetical! No matter what, there’s always going to be something pulling on you with gravity.
If you’ve taken our Electricity and Magnetism class, you’ve seen this device before! You press a button and an electric arc rises to the top of two tall wires. This is the Jacob’s Ladder! But what’s happening here?
The base of the Ladder is a transformer — a device that changes an incoming voltage. In the Ladder’s case, it increases it by a huge amount. That voltage is put into one of the vertical wires, increasing its electric potential. The electricity needs to flow somewhere, so it ionizes the air to jump to the other vertical wire. As the electricity arcs, it heats up the ionized air, which causes it to rise. As the wire get further apart, it becomes more and more difficult for the electricity to reach, and the arc eventually stops. Then the transformer builds up the electric potential again, repeating the process all over again. Though as electricity flows through the wires, they heat up. The hotter they are, the slower the electricity flows. Eventually, you’ll notice the arc having trouble getting to the top as it travels slower and slower.
This is just one of the many cool electricity demos we have at AstroCamp! Be sure to check out this and all the others on your trip.
There are countless stars that we can see in our night sky, and all of them are unique. Some are dim, barely visible without a telescope. Others are bright and can be seen even in the most light-polluted areas. We measure the brightness of these stars using the magnitude scale.
The magnitude scale seems a little backwards. The lower the number, the brighter the object is; and the higher the number, the dimmer it is. This scale is logarithmic and set so that every 5 steps up equals a 100 times decrease in brightness. So magnitude 10 is 100 times dimmer than magnitude 5, which is 100 times dimmer than magnitude 0.
Our sun — the brightest thing in our sky — is magnitude -26.7. Other objects like the moon or nearby planets have negative magnitudes, and other stars vary greatly. The dimmest objects humans can see with the naked eye is around 6; any dimmer and we need to use a telescope.
What we’ve been talking about is apparent magnitude. It measures the brightness of stars and other celestial objects as they are as viewed from Earth, without taking into account distance or actual luminosity. It’s fine for describing what things look like from here, but it isn’t very good at describing how much light those objects are actually emitting. Our moon is incredibly bright to us, but if it were farther away from us, its brightness would decrease a lot.
To better compare the brightness of objects to each other, we use the absolute magnitude scale. The logarithmic scale is the same, but we calculate what an object’s apparent magnitude would be if it were exactly 10 parsecs away from Earth (about 33 light-years away). This way, we eliminate distance as a factor for comparing the brightness of space objects.
As you can see, the brightness measurement of stars is a little more complicated than it first appears. It may also be difficult to really visualize the difference in brightness. But it’s an easy task to find a catalog of stars, go outside, and experience it yourself!
On January 20, around 8.30 PST, the Earth is going to pass directly between the moon and the sun. This is normally the time when the moon would be full, reflecting the sun’s rays back to us on Earth with all of the side facing towards us. But the Earth’s shadow is going to fall across the moon’s surface, giving us a SUPER BLOOD WOLF MOON.
This is a silly name, we can all agree on that. But more than just being a ridiculous sequence of words, the Super Blood Wolf Moon combines several colloquial names in a strange but accurate way. The word “Super” comes from the term “super moon,” a phenomenon where the full moon occurs at the same time as the moon’s closest approach to Earth. The moon appears slightly larger during this time, though not by much. “Blood” comes from the reddish color the moon becomes during the lunar eclipse as red and orange light gets refracted through the Earth’s atmosphere as it travels towards the moon. “Wolf” is an old name for January’s full moon, coming from Native American tradition. Each other month has a name for its full moon, too!
So there you have it. Super Blood Wolf Moon definitely isn’t a made-up thing, and though your friends and family won’t believe you when you tell them about it, it’s going to be an incredible event that you won’t want to miss!
Every day, about 40 tons of space rocks reach the top of Earth’s atmosphere. These asteroids come in many different sizes and have been floating around in space for billions of years. Once they reach the Earth, however, they become meteors — more colloquially known as shooting stars.
Friction with the air causes the rock to ignite and luminesce. Most of these are pretty dim and can only be seen at night. And most of these are also too small for any chunk to reach the surface of the Earth; the heat and friction vaporize the meteors completely. However, sometimes the meteor is large enough to withstand the friction until it hits the surface. These are classified as meteorites. Very few of these are large enough to leave a significant impact, but every once in a while, a large meteorite touches down. When this happens, it compresses the surface, which will decompress moments later as a shockwave, traveling through the rock and carving out a crater.
Very rarely, an extinction-level event meteor collides with our planet. Such an event happened 66 million years ago, and is a possible cause of the major extinction event that killed all the dinosaurs. The impact is hypothesized to be a billion time stronger than the first atomic bombs, sending ash and dust into the air that blocked sunlight for more than a full year.
Thankfully, such events are incredibly rare, so the most you’ll have to be worried about is a small dent in your car — and even that is unlikely to happen!
At first glance, a Tippe Top looks like a normal spinning top. A few moments after you spin it however, the tippe top flips over and begins spinning on its thin stem, raising its center of mass upwards! This marvel of a toy stumped physicists and was popular among many well-known figures in the mid-1900s.
The strange mechanics that add potential energy to the toy fascinated Nobel Prize winners Niels Bohr and Wolfgang Pauli. It was originally designed in the mid-1800s, but was reinvented in the 1950s and sold as a toy. Very popular at the time, it drew the attention of physicists who sought to figure out exactly what was happening.
In order to flip over and raise its center of mass, the tippe top needs to translate some of its rotational momentum. It does so because its center of mass is actually lower than its geometrical center. As it spins, the rotational axis is offset from the point of contact with the table, which causes the top to trace out a circle on the table.
The friction with the table applies a torque that causes the top to tip over, changing its angular momentum. When it becomes horizontal, the top actually reverses its direction of spin! Once the stem hits the table, the torque causes the top to flip over! It’s spinning slower than it was before, and that energy has gone into gravitational potential energy!
It just goes to show that even simple-looking toys can have some cool and challenging physics behind them! You just have to stop and think about how they actually work.
One of AstroCamp’s best activities is our ropes course! From zipline to skycoaster, we encourage kids to push themselves to overcome the challenge. But there’s a lot of unseen work that goes into setting up these activities! One of the most important jobs is getting all the knots tied!
We use an assortment of different knots on our ropes courses. If you want a step-by-step instruction of how to tie a few of them, check out the video above!
The “Figure-8” and “Figure-8 on a Bight” knots feature heavily on the ropes course. They’re easy and strong knots, and feature heavily in rock climbing. The allow us to connect carabiners to the participants. The Figure-8 on a Bight is usually accompanied by some sort of stopper knot to prevent the line from slipping. If you’ve ever been attached to a rope at AstroCamp, it’s most likely been via this knot!
The third knot we show in the video is the “Alpine Butterfly.” It’s a unique knot in that it can be tied at any point on the rope without needing to access either end. It creates a fixed loop, where a carabiner or another rope can be attached. We use this knot on the skycoaster to retrieve the line after you’ve pulled the release cord. It’s also how we attach you to the haul rope that you use to get the skycoaster participant up into the air in the first place!
There are quite a few other knots that we use on the ropes course, but these are three of the most common. With just a small length of rope, you can practice them and become a ropes master!
We would like to thank you for visiting our blog. AstroCamp is a hands-on physical science program with an emphasis on astronomy and space exploration. Our classes and activities are designed to inspire students toward future success in their academic and personal pursuits. This blog is intended to provide you with up-to-date news and information about our camp programs, as well as current science and astronomical happenings. This blog has been created by our staff who have at least a Bachelors Degree in Physics or Astronomy, however it is not uncommon for them to have a Masters Degree or PhD. We encourage you to also follow us on Facebook, Instagram, Google+, Twitter, and Vine to see even more of our interesting science, space and astronomy information. Feel free to leave comments, questions, or share our blog with others. Please visit www.astrocampschool.org for additional information. Happy Reading!