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!
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!
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!
During our Space Night, you’ll eventually find yourself in an area with tools that allow you to look at the beautiful night sky. Each station has its own set of binoculars, Dobsonian telescope, and either a Celestron or Meade telescope mounted on an electric motor. But in the center of the telescope area sits another type of telescope. This telescope has the ability to take images of objects that are too dim for our eyes to see. This is our CCD telescope!
At first glance, there’s not much different about it. It’s a little bigger, its mount is different than the others, but instead of an eyepiece attached to the end of it, there is a special camera mounted to the front. This camera has computer cables that allow it to be controlled by a special laptop, and it can take photos of very dim space objects.
The CCD chip is a very sensitive device. It can count individual photons (particles of light) as they hit the sensor and then convert them into electrons. The more a particular area is struck by photons, the more electrons it will generate. This electrical signal is what gives us our image.
While looking through a telescope with an eyepiece, our eyeballs are doing the equivalent of taking many images every second. The telescope helps us see dimmer objects than we’d normally perceive, but there’s nothing we can do about taking longer exposures with our eyes. The CCD camera changes that. It can keep its sensors on for a long amount of time, gathering and collecting light for thousands of times greater than our eyes can.
The CCD onboard the Kepler Space Telescope. Credit: NASA
These telescopes are used all around the world by amateur and professional astronomers. They can also be found beyond our planet in space telescopes like Hubble or Kepler! These devices allow us to view faraway objects and help us unravel the mysteries of our universe.
During the 1960s, NASA had the daunting task of landing a person on the moon. When John F. Kennedy announced the goal to put a man on the moon by the end of the decade, they had only recently sent Alan Shepard into space for the first time. It would be another nine months before John Glenn would become the first American to orbit the Earth. NASA would need to perfect every step in just 8 short years. The first step is to reach the altitude of the moon. In order to get there efficiently, we must perform a maneuver known as a “Hohmann Transfer.” Designed to minimize fuel consumption, it allows us to build lighter, cheaper spacecrafts.
But once the spacecraft is headed to the moon, it will be going too fast to be fully captured by the moon’s gravity. At this speed, it will slingshot around it and head back to Earth. To insert itself into lunar orbit, the spaceship needs to slow down. The only way it can do this is by burning its rocket in the direction it’s flying. Once it’s burned for long enough, the speed of the rocket is low enough to establish a lunar orbit.
Both the US and the USSR had been trying to refine this technique since the late 1950s, with little success. Both nations had succeeded in getting impactors and landers onto the moon, but it wasn’t until November 1966 when NASA successfully put an unmanned craft into orbit. In December 1968, Apollo 8 would become the first manned spaceship to orbit the Earth.
Getting to lunar orbit was tricky, but once NASA engineers could consistently make the calculations correctly, they advanced to the next challenge – getting a manned lander onto the surface of the moon.
Believe it or not, supernovas have been known to humans for thousands of years. That’s not to say that ancient civilizations knew exactly what was happening when they saw them, but they were witnesses to some of the most powerful events in our universe. When certain stars reach the end of their lifetime, they explode in a spectacular way. These stars are most commonly very large, anywhere from a few times as massive as our sun to a few hundred times as large. These supernovas emit an incredible amount of light, the brightest of which can be billions of times more luminous than our sun.
However, these explosions occur fairly rarely. Scientists believe that only a handful happen in the Milky Way every thousand years. But when they do, they are bright enough to be seen from Earth. In the year 1054, Chinese astronomers observed a new star near the constellation of Taurus. It quickly grew, until it appeared even brighter than the planets in our solar system. This visitor star lasted for about two years, eventually dimming until it could no longer be seen.
In the 1700s, astronomer John Bevis discovered the Crab Nebula in the Taurus constellation, and it was later recorded by Charles Messier as the first object in his 110-object catalogue. Two hundred years later in 1928, another astronomer named Edwin Hubble connected the records of the Chinese astronomers and the object known as the Crab Nebula to be the same thing, separated by almost a thousand years. His theory was that the nebula was the remnants of a supernova, which was the source of the visitor star.
This turned out to be correct, and later it was determined that at the center of the nebula was a pulsar – a very quickly spinning neutron star left over by the explosion. This revelation led to the discovery of dozens of other supernova remnants. Over the past few decades, research into supernovas has greatly expanded our knowledge of astronomy and stellar evolution. We haven’t seen a supernova in our galaxy for a long time, and we’re due one in the near future. Astronomers have identified several stellar candidates that may explode sometime soon – and when one of them does, we’ll get to experience another visitor star for the first time in hundreds of years.
Have you ever really sat down to think about how much space there is in the universe? It’s pretty inconceivable, but there are some useful tools that can help put things in perspective. You’ve already seen a scale model of our solar system by mass, so here is a model of the space between our planets that can fit in your pocket!
What you need:
Long strip of paper
First, cut a strip of paper long enough that it roughly spans the distance of your arms. Then, have a marker handy to be ready to indicate where each planet will lie.
Label one end of the strip as the sun and the other as Pluto/Kuiper belt.
This will show the full distance between the sun and the outer reaches of the solar system.
Fold the paper in half and crease it. That line is for Uranus, it is roughly halfway between Pluto and the sun!
Fold it in half again (it should now be in quarters). The crease between Uranus and Pluto is for Neptune.
The crease that is between the sun and Uranus is for Saturn.
Now fold the sun to Saturn and mark Jupiter in that crease.
We have completed all of the gaseous outer planets, meaning that all that is left are the rocky inner planets, which fit between the sun and Jupiter!
Fold the sun to Jupiter and label it as the asteroid belt, the area in our solar system where some of the largest known asteroids live.
Now fold the sun to the asteroid belt. This is where Mars goes.
We will complete the remaining three planets in the last step.
Fold the sun to Mars, then fold in half again. Closest to the sun is Mercury followed by Venus, then Earth.
Take a look, roll it up, and there you have it! A basic scale model of the distances between the planets of our solar system that can fit in your pocket. Would you have been able to guess how much space there is relatively between our planets? Did any of the spacings surprise you?
We are extremely lucky to have a rare piece of equipment on display here at AstroCamp. On loan from JPL, we have the model of the Spirit and Opportunity rovers! As a part of our Mars exploration class, “Expedition Valles Marineris”, the model is used to show our campers a full scale example of what NASA and other space agencies have sent to explore our solar system.
Spirit and Opportunity are just two of 14 artificial objects on Mars, landing on the red planet in January 2004. NASA last communicated with Spirit on March 22, 2010, but Opportunity is still going strong!
They were sent to explore two different sites on opposite sides of Mars and their purpose was to collect rocks and soil samples looking for clues of past water activity. A few characteristics built into them to enable this exploration are: Solar panels, the PanCam, a visible light spectrometer, an x-ray spectrometer, rock abrasion tool, and microscope, to name a few. A fun characteristic that they share is that they have tire markings which spell out “NASA” in morse code as they roll through the red dust.
However, did you know that rovers are not the only types of explorers that we have sent or will send to space? There are also:
Astronauts and cosmonauts
The Gecko Gripper
But, with the help from our future scientists and engineers, like those campers who attend AstroCamp, there is no telling what the future can hold! So what impact do you think you could create for the future of space?
We can’t take our eyes off it, it helps control our tides, and wolves howl at it; can you name what “it” is? You probably guessed correctly, it’s Luna, also known as the moon! The moon is the largest satellite of Earth, and one of the only natural satellites. This means that there may be other satellites out there orbiting around Earth (thanks to space junk and our cell phone providers), but it is by far the largest and amongst the only that came from space to orbit our home planet. Our moon is also the brightest object in our night sky, so bright in fact that you can sometimes see it during the day. However, the moon seems to be constantly changing. How can that be possible?
To demonstrate what is happening, you can do an easy experiment at home. All you need is a single light source (representing the sun), your face (representing Earth), and a ball or your fist (modeling the moon).
Earth’s gravity has the moon tidally locked, meaning the same half of the moon is always facing Earth, and the other half is always facing away (the dark side of the moon). Since it is tidally locked, your model of the moon does not need to spin. All you have to do now is put your moon between your face and model of the sun and start to rotate counterclockwise (the same direction that Earth spins).
When the moon is between the sun and the Earth, light from the sun cannot reflect from the moon to Earth. This phase is called a “New Moon”. As you keep rotating you will first see a waxing crescent, then: the first quarter, waxing gibbous, full moon (Earth is between the moon and the sun), waning gibbous, third quarter, waning crescent, then back to New Moon. If you keep rotating the cycle will continue on and on. For our real moon this cycle will take about 29 days to be completed.
You can easily keep track of this cycle on your own as well. All you need to do is step outside each night and make some observations. Take note of what the day and time is, and what the moon looks like to you. Once you have done this for a couple of weeks you should be able to predict what you will see next! So go ahead, give it a try for yourself and have fun.
A constellation is a group of stars that are considered to form imaginary outlines or meaningful patterns on the celestial sphere. They typically represent animals, mythological people, gods or creatures. There are 88 modern constellations, but just because those are the ones that are recognized doesn’t mean that one you make up is less valid.
The stars that constellations are comprised of are not necessarily stars that are near each other. So how do they appear that way? It’s all about perspective.
Take for example, The Big Dipper, an asterism in Ursa Major. An asterism is a smaller part of a constellation, usually with more noticeable stars. The Big Dipper is composed of seven bright stars: Alkaid, Mizar, Alioth, Megrez, Phecda, Merak, and Dubhe. Together, they appear to be in the shape of a spoon (use your imagination). However, they are all different distances away from Earth as well as from each other. Their distances from Earth respectively are roughly: 104 ly, 78 ly, 82.5 ly, 80.5 ly, 83 ly, 79.5 ly, and 123.6 ly.
But if you simply change your perspective, or location from which you’re looking at them, then the picture changes! Unfortunately, since we are all on Earth, our perspective can not move enough to make a big difference.
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!