Teachable Moments | January 8, 2021
NASA's Perseverance Rover Lands on Mars
Learn how, why, and what Perseverance will explore on Mars, plus find out about an exciting opportunity for you and your students to join in the adventure!
In the News
On Feb. 18, NASA's Perseverance Mars rover touched down on the Red Planet after a seven-month flight from Earth. Only the fifth rover to land on the planet, Perseverance represents a giant leap forward in our scientific and technological capabilities for exploring Mars and the possibility that life may have once existed on the Red Planet.
Here, you will:
- Meet the Perseverance Mars rover and find out what it's designed to do.
- Learn about an exciting opportunity to get your classroom, educational organization, or household involved with the Mission to Mars Student Challenge.
Why It's Important
You might be wondering, "Isn't there already a rover on Mars?” The answer is yes! The Curiosity rover landed on Mars in 2012 and has spent its time on the Red Planet making fascinating discoveries about the planet's geology and environment – setting the stage for Perseverance. So, why send another rover to Mars? The lessons we’ve learned from Curiosity coupled with advancements in technology over the last decade are allowing us to take the next big steps in our exploration of Mars, including looking for signs of ancient microbial life, collecting rock samples to bring to Earth one day, and setting the stage for a potential future human mission to the Red Planet.
More specifically, the Perseverance Mars rover has four science objectives:
- Identify past environments on Mars that could have supported microbial life
- Seek signs of ancient microbial life within the rocks and soil using a new suite of scientific instruments
- Collect rock samples of interest to be stored on the surface for possible return by future missions
- Pave the way for human exploration beyond the Moon
With these science objectives in mind, let's take a look at how the mission is designed to achieve these goals – from its science-rich landing site, Jezero Crater, to its suite of onboard tools and technology.
How It Works
Follow the Water
![A false-color satellite image of Jezero Crater is green and yellow around the edges with a large blue circular crater in the middle.](https://mars.nasa.gov/imgs/mars2020/jezerocratermap.jpg)
Lighter colors represent higher elevation in this image of Jezero Crater on Mars, the landing site for the Perseverance rover. The black oval indicates the area in which the rover will touch down, also called a landing ellipse. Image Credit: NASA JPL/Caltech/MSSS/JHU-APL/ESA | › Full image and caption
While present-day Mars is a cold, barren planet, science suggests that it was once very similar to Earth. The presence of clay, dried rivers and lakes, and minerals that formed in the presence of water provide extensive evidence that Mars once had flowing water at its surface. As a result, a mission looking for signs of ancient life, also known as biosignatures, should naturally follow that water. That’s because water represents the essential ingredient for life as we know it on Earth, and it can host a wide variety of organisms.
This is what makes Perseverance's landing site in Jezero Crater such a compelling location for scientific exploration. The crater was originally formed by an ancient meteorite impact about 3.8 billion years ago, and it sits within an even larger, older impact basin. The crater also appears to have once been home to an ancient lake fed by a river that formed the delta where Perseverance will begin its exploration, by exploring the foot of the river delta.
Take a tour of Perseverance's landing site in this animated flyover of the Martian surface. Credit: NASA/JPL-Caltech | Watch on YouTube
Tools of the Trade
Perseverance will begin its scientific exploration with the assistance of an array of tools, also known as science instruments.
![An illustration of the rover is shown with each of its science instruments deployed and identified.](https://mars.nasa.gov/system/resources/detail_files/25045_Perseverance_Mars_Rover_Instrument_Labels-web.jpg)
This artist's concept shows the various science tools, or instruments, onboard the rover. Image credit: NASA/JPL-Caltech | › Learn more about the rover's science instruments
Like its predecessor, Perseverance will have a number of cameras – 23, in fact! – serving as the eyes of the rover for scientists and engineers back on Earth. Nine of these cameras are dedicated to mobility, or tracking the rover's movements; six will capture images and videos as the rover travels through the Martian atmosphere down to the surface, a process known as entry, descent, and landing; and seven are part of the science instrumentation.
![The SuperCam instrument is shown on a laboratory table before being installed on the rover.](https://mars.nasa.gov/layout/mars2020/images/supercam-web.jpg)
SuperCam's mast unit before being installed atop the Perseverance rover's remote sensing mast. The electronics are inside the gold-plated box on the left. The end of the laser peeks out from behind the left side of the electronics. Image credit: CNES | › Learn more about SuperCam
![Six pump-like structures control a rectangular metal instrument in this animated image.](https://www.jpl.nasa.gov/images/mars2020/20200922/PIA24094-640.gif)
PIXL can make slow, precise movements to point at specific parts of a rock's surface so the instrument's X-ray can discover where – and in what quantity – chemicals are distributed in a given sample. This GIF has been considerably sped up to show how the hexapod moves. Image credit: NASA/JPL-Caltech | › Learn more about PIXL
![A small camera sits in gold-color housing on a white rover body.](https://mars.nasa.gov/layout/mars2020/images/sherloc-web.jpg)
A close-up view of an engineering model of SHERLOC, one the instruments aboard NASA's Perseverance Mars rover. Credit: NASA/JPL-Caltech | › Learn more about SHERLOC
Navcam, located on the mast (or "head") of the rover, will capture images to help engineers control the rover. Meanwhile, Mastcam-Z, also on the rover’s mast, can zoom in, focus, and take 3D color pictures and video at high speed to allow detailed examination of distant objects. A third camera, Supercam, fires a small laser burst to excite compounds on the surface and determine their composition using spectroscopy. Supercam is also equipped with a microphone. This microphone (one of two on the rover) will allow scientists to hear the pop the laser makes upon hitting its target, which may give scientists additional information about the hardness of the rock.
Leaning more toward chemistry, the Planetary Instrument for X-Ray Lithochemistry (PIXL) will allow us to look at the composition of rocks and soil down to the size of a grain of salt. Elements respond to different types of light, such as X-rays, in predictable ways. So by shining an X-ray on Martian rocks and soil, we can identify elements that may be part of a biosignature.
Meanwhile, a device called SHERLOC will look for evidence of ancient life using a technique called Deep UV Raman spectroscopy. Raman spectroscopy can help scientists see the crystallinity and molecular structure of rocks and soil. For example, some molecules and crystals luminesce, or emit light, when exposed to ultraviolet – similar to how a blacklight might be used to illuminate evidence in a crime scene. Scientists have a good understanding of how chemicals considered key to life on Earth react to things like ultraviolet light. So, SHERLOC could help us identify those same chemicals on Mars. In other words, it can contribute to identifying those biosignatures we keep talking about.
Rounding out its role as a roving geologist on wheels, Perseverance also has instruments for studying beneath the surface of Mars. An instrument called the Radar Imager of Mars Subsurface Experiment (RIMFAX) will use ground-penetrating radar to analyze depths down to about 100 feet (30 meters) below the surface. Mounted on the rear of the rover, RIMFAX will help us understand geological features that can't be seen by the other cameras and instruments.
The rover's suite of instruments demonstrates how multiple scientific disciplines – chemistry, physics, biology, geology, and engineering – work in concert to further our understanding of Mars and help scientists uncover whether life ever existed on the Red Planet.
Next Generation Tech
At NASA, scientists and engineers are always looking to push the envelope and, while missions such as Perseverance are ambitious in themselves, they also provide an opportunity for NASA to test new technology that could be used for future missions. Two excellent examples of such technology joining Perseverance on Mars are MOXIE and the first ever Mars helicopter, Ingenuity.
![Engineers in white smocks lower a gold-colored cube into the rover](https://mars.nasa.gov/system/resources/detail_files/22395_PIA23154-16.jpg)
Members of Perseverance mission team install MOXIE into the belly of the rover in the cleanroom at NASA's Jet Propulsion Laboratory in Southern California. Image credit: NASA/JPL-Caltech | › Full image and caption
MOXIE stands for the Mars Oxygen In-Situ Resource Utilization Experiment. Operating at 800 degrees Celsius, MOXIE takes in carbon dioxide (CO2) from the thin Martian atmosphere and splits those molecules into pure oxygen using what is called a catalyst. A catalyst is a chemical that allows for reactions to take place under conditions they normally wouldn’t. MOXIE provides an incredible opportunity for NASA to create something usable out of the limited resources available on Mars. Over the duration of the rover's mission, MOXIE will run for a total of one hour every time it operates, distributed over the course of the prime mission timeframe, to determine whether it can reliably produce breathable oxygen. The goal of operating this way is to allow scientists to determine the performance across a variety of environmental conditions that a dedicated, human-mission-sized oxygen plant would see during operations - day versus night, winter versus summer, etc. Oxygen is of great interest for future missions not just because of its necessity for future human life support on Mars, but also because it can be used as a rocket propellant, perhaps allowing for future small-scale sample return missions to Earth.
![The helicopter with four long blades, a cube-shape body and long skinny legs sites in the forground with the wheels of the rover visible to its right.](https://mars.nasa.gov/system/resources/detail_files/25117_PIA23720-16.jpg)
This artist's concept shows Ingenuity, the first Mars helicopter, on the Red Planet's surface with Perseverance (partially visible on the left) in the distance. Image credit: NASA/JPL-Caltech | › Full image and caption
The Mars Ingenuity helicopter is likewise an engineering first. It is a technology demonstration to test powered flight on Mars. Because the Martian atmosphere is so thin, flight is incredibly difficult. So, the four-pound (1.8-kilogram), solar powered helicopter is specially designed with two, four-foot (1.2-meter) long counter-rotating blades that spin at 2,400 rotations per minute. In the months after Perseverance lands, Ingenuity will drop from the belly of the rover. If all goes well, it will attempt test flights of increasing difficulty, covering incrementally greater heights and distances for about 30 days. In the future, engineers hope flying robots can allow for a greater view of the surrounding terrain for robotic and human missions alike.
Teach It
Take part in a worldwide “teachable moment” and bring students along for the ride as NASA lands the Perseverance rover on Mars February 18. Science communicator and host of “Emily’s Wonder Lab” on Netflix, Emily Calandrelli, shares how you can join the adventure with your students! | Register on Eventbrite
The process of landing on Mars with such an advanced mission is no doubt an exciting opportunity to engage students across all aspects of STEM – and NASA wants to help teachers, educators and families bring students along for the adventure with the Mission to Mars Student Challenge. This challenge will lead students through designing and building a mission to Mars with a guided education plan and resources from NASA, listening to expert talks, and sharing student work with a worldwide audience.
Learn more about the challenge and explore additional education resources related to the Perseverance Mars rover mission at https://go.nasa.gov/mars-challenge
Watch the Landing
The next chapter of Perseverance’s journey takes place on Feb. 18 at 12 p.m. PST (3 p.m. EST), when the mission reaches Mars after seven months of travelling through space. Join NASA as we countdown to landing with online events for teachers, students, and space enthusiasts! The landing day broadcast can be seen on NASA TV and the agency's website starting at 11:15 a.m. PST (2:15 p.m. EST). For a full listing of online events leading up to and on landing day, visit the mission's Watch Online page.
Follow landing updates on NASA's Twitter, Facebook and Instagram accounts.
Explore More
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NASA's Mission to Mars Student Challenge
Take part in a worldwide "teachable moment" and bring students along for the ride as NASA lands a rover on Mars February 18!
- Teachable Moment
Meet Perseverance, NASA's Next Mars Rover
Find out how the rover has been "souped up" with science instruments, cameras and technologies to explore Mars in new ways – plus, what to expect on launch day.
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Mission to Mars Unit
In this standards-aligned unit, students learn about Mars, design a mission to explore the planet, build and test model spacecraft and components, and engage in scientific exploration.
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NASA #CountdownToMars STEM Toolkit
Explore links to activities, lessons, interactives, social media, and more resources from NASA to participate in the Perseverance Mars rover mission.
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Exploring Mars Lessons
Get students engaged in the excitement of NASA's next mission to Mars with standards-aligned STEM lessons.
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Meet JPL Interns of Mars 2020
Read stories about interns helping prepare NASA's next Mars rover for its launch this summer.
- Education Webinars
Teaching Space With NASA
Watch education webinars featuring NASA experts and education specialists and register to ask questions during live Q&As. Plus, explore related education resources.
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Exploring Mars Activities
Make a cardboard rover, design a Mars exploration video game, learn about Mars in a minute and explore more STEM activities for students.
- Resources for Families
Learning Space With NASA at Home
Explore space and science activities students can do with NASA at home. Watch video tutorials for making rockets, Mars rovers, Moon landers and more. Plus, find tips for learning at home!
More Resources From NASA
TAGS: Mars, Perseverance, Mars 2020, Science, Engineering, Robotics, Educators, Teachers, Students, Teachable Moments, Teach, Learn, Mars Landing
Teachable Moments | June 17, 2020
Meet Perseverance, NASA's Newest Mars Rover
Perseverance, NASA's most advanced Mars rover yet, is scheduled to leave Earth for its seven-month journey to the Red Planet this summer.
Only the fifth NASA rover destined for Mars, Perseverance is designed to build on the work and scientific discoveries of its predecessors. Find out more about the rover's science goals and new technologies below. Plus, learn how you can bring the exciting engineering and science of this mission to students with lessons and DIY projects covering topics like biology, geology, physics, mathematics, engineering, coding and language arts.
Why It's Important
Perseverance may look similar to Curiosity – the NASA rover that's been exploring Mars since 2012 – but the latest rover's new science instruments, upgraded cameras, improved onboard computers and new landing technologies make it uniquely capable of accomplishing the science goals planned for the mission.
![](https://mars.nasa.gov/system/resources/detail_files/25045_Perseverance_Mars_Rover_Instrument_Labels-web.jpg)
Diagram of the Perseverance Mars rover's science instruments. Credit: NASA/JPL-Caltech | + Expand image
Looking for signs of habitability
The first of the rover's four science goals deals with studying the habitability of Mars. The mission is designed to look for environments that could have supported life in the past.
Perseverance will land in Jezero Crater, a 28-mile-wide (45-kilometer-wide) crater that scientists believe was once filled with water. Data from orbiters at the Red Planet suggest that water once flowed into the crater, carrying clay minerals from the surrounding area, depositing them in the crater and forming a delta. We find similar conditions on Earth, where the right combination of water and minerals can support life. By comparing these to the conditions we find on Mars, we can better understand the Red Planet's ability to support life. The Perseverance rover is specially designed to study the habitability of Mars' Jezero Crater using a suite of scientific instruments, or tools, that can evaluate the environment and the processes that influence it.
This animated flyover shows the area where Perseverance will land in February 2021 and is narrated by the mission's project scientist, Ken Farley. Credit: NASA/JPL-Caltech | › Learn more about the mission's landing site | Watch on YouTube
Seeking signs of ancient life
The rover's second science goal is closely linked with its first: Perseverance will seek out evidence that microbial life once existed on Mars in the past. In doing so, the mission could make progress in understanding the origin, evolution and distribution of life in the universe – the scientific field known as astrobiology.
It's important to note that the rover won't be looking for present-day life. Instead, its instruments are designed to look for clues left behind by ancient life. We call those clues biosignatures. A biosignature might be a pattern, object or substance that was created by life in the past and can be identified by certain properties, such as chemical composition, mineralogy or structure.
To better understand if a possible biosignature is really a clue left behind by ancient life, we need to look for biosignatures and study the habitability of the environment. Discovering that an environment is habitable does not automatically mean life existed there and some geologic processes can leave behind biosignature-like signs in non-habitable environments.
Collecting samples
Perseverance's third science goal is to gather samples of Martian rocks and soil. The rover will leave the samples on Mars, where future missions could collect them and bring them back to Earth for further study.
Scientists can learn a lot about Mars with a rover like Perseverance that can take in situ (Latin for "on-site") measurements. But examining samples from Mars in full-size laboratories on Earth can provide far more information about whether life ever existed on Mars than studying them on the Martian surface.
Perseverance will take the first step toward making a future sample return possible. The rover is equipped with special coring drill bits that will collect scientifically interesting samples similar in size to a piece of chalk. Each sample will be capped and sealed in individual collection tubes. The tubes will be stored aboard the rover until the mission team determines the best strategic locations on the planet's surface to leave them. The collection tubes will stay on the Martian surface until a potential future campaign collects them for return to Earth. NASA and the European Space Agency are solidifying concepts for the missions that will complete this campaign.
Preparing for future astronauts
![Astronauts, an exploration vehicle and a habitat are shown among a rich orange landscape](https://mars.nasa.gov/system/resources/detail_files/22530_PIA23302-web.jpg)
This artist's concept depicts astronauts and human habitats on Mars. The Perseverance Mars rover will carry a number of technologies that could pave the way for astronauts to explore Mars. Credit: NASA | + Expand image
Like the robotic spacecraft that landed on the Moon to prepare for the Apollo astronauts, the Perseverance rover's fourth science goal will help pave the way for humans to eventually visit Mars.
Before humans can set foot on the Red Planet, we need to know more about conditions there and demonstrate that technologies needed for returning to Earth, and survival, will work. That’s where MOXIE comes in. Short for Mars Oxygen In-Situ Resource Utilization Experiment, MOXIE is designed to separate oxygen from carbon dioxide (CO2) in Mars' atmosphere. The atmosphere that surrounds the Red Planet is 96% CO2. But there's very little oxygen – only 0.13%, compared with the 21% in Earth’s atmosphere.
Oxygen is a crucial ingredient in rocket fuel and is essential for human survival. MOXIE could show how similar systems sent to Mars ahead of astronauts could generate rocket fuel to bring astronauts back to Earth and even create oxygen for breathing.
Join JPL mechanical engineer Mike Meacham to find out how the MOXIE instrument on NASA's Perseverance Mars rover is designed to convert carbon dioxide from Mars' atmosphere into oxygen. Credit: NASA/JPL-Caltech | Watch on YouTube
Flying the first Mars helicopter
Joining the Perseverance rover on Mars is the first helicopter designed to fly on another planet. Dubbed Ingenuity, the Mars Helicopter is a technology demonstration that will be the first test of powered flight on another planet.
The lightweight helicopter rides to Mars attached to the belly of the rover. After Perseverance is on Mars, the helicopter will be released from the rover and will attempt up to five test flights in the thin atmosphere of Mars. After a successful first attempt at lifting off, hovering a few feet above the ground for 20 to 30 seconds and landing, the operations team can attempt incrementally higher and longer-distance flights. Ingenuity is designed to fly for up to 90 seconds, reach an altitude of 15 feet and travel a distance of nearly 980 feet. Sending commands to the helicopter and receiving information about the flights relayed through the rover, the helicopter team hopes to collect valuable test data about how the vehicle performs in Mars’ thin atmosphere. The results of the Mars Helicopter's test flights will help inform the development of future vehicles that could one day explore Mars from the air. Once Ingenuity has completed its technology demonstration, Perseverance will continue its mission on the surface of the Red Planet.
Join JPL mechanical engineer Mike Meacham to learn about the first helicopter designed for Mars. Credit: NASA/JPL-Caltech | Watch on YouTube
How It Works
Before any of that can happen, the Perseverance Mars rover needs to successfully lift off from Earth and begin its journey to the Red Planet. Here's how the launch is designed to ensure that the spacecraft and Mars are at the same place on landing day.
About every 26 months, Mars and Earth are at points in their orbits around the Sun that allow us to launch spacecraft to Mars most efficiently. This span of time, called a launch period, lasts several weeks. For Perseverance, the launch period is targeted to begin at 4:50 a.m. PDT (7:50 a.m. EDT) on July 30 and end on Aug. 15. Each day, there is a launch window lasting about two hours. If all conditions are good, we have liftoff! If there's a little too much wind or other inclement weather, or perhaps engineers want to take a look at something on the rocket during the window, the countdown can be paused, and teams will try again the next day.
Regardless of when Perseverance launches during this period, the rover will land on Mars on Feb. 18, 2021, at around 12:30 PST. Engineers can maintain this fixed landing date because when the rover launches, it will go into what's called a parking orbit around Earth. Depending on when the launch happens, the rover will coast in the temporary parking orbit for 24 to 36 minutes. Then, the upper stage of the rocket will ignite for about seven minutes, giving the spacecraft the velocity it needs to reach Mars.
Like the Curiosity rover, Perseverance will launch from Launch Complex 41 at Cape Canaveral Air Force Station in Florida on an Atlas V 541 rocket – one of the most powerful rockets available for interplanetary spacecraft.
Watch a live broadcast of the launch from the Kennedy Space Center on NASA TV and the agency’s website. Visit the Perseverance rover mission website to explore a full listing of related virtual events and programming, including education workshops, news briefings and conversations with mission experts. Follow launch updates on NASA's Twitter, Facebook and Instagram accounts.
Teach It
The launch of NASA's next Mars rover and the first Mars Helicopter is a fantastic opportunity to engage students in real-world problem solving across the STEM fields. Check out some of the resources below to see how you can bring NASA missions and science to students in the classroom and at home.
Virtual Education Workshops
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Teaching Space With NASA - Engineering the Perseverance Mars Rover
In this one-hour live workshop, NASA experts will provide an in-depth look at the engineering behind the Perseverance Mars rover. Register to join the Q&A with our experts.
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Teaching Space With NASA - Exploring Mars Science With the Perseverance Mars Rover
In this one-hour live workshop, we’ll get an in-depth look at how Perseverance will explore the science of Mars, building on our understanding of the Red Planet and preparing for future human missions. Register to join the Q&A with our experts.
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Teaching Space With NASA
Join NASA experts and education specialists for virtual education workshops. Ask questions, get teaching resources and share the excitement of space exploration with students.
Lessons for Educators
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Mission to Mars Unit
In this standards-aligned unit, students learn about Mars, design a mission to explore the planet, build and test model spacecraft and components, and engage in scientific exploration.
Grades 3-8
Time Varies
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Collection: Exploring Mars
Explore a collection of standards-aligned lessons for educators all about engineering and preparing NASA spacecraft for Mars.
Grades K-12
Time Varies
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Collection: Preparing for Mars
Explore a collection of standards-aligned lessons for educators all about engineering and preparing NASA spacecraft for Mars.
Grades K-12
Time Varies
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Collection: Launching to Mars
Explore a collection of standards-aligned lessons for educators all about launching NASA spacecraft to Mars.
Grades K-12
Time Varies
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Collection: Landing on Mars
Explore a collection of standards-aligned lessons for educators all about landing NASA spacecraft on Mars.
Grades K-12
Time Varies
Activities for Students
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Collection: Exploring Mars
Make a cardboard rover, design a Mars exploration video game and explore more STEM projects, slideshows and videos for students.
Subject Varies
Grades K-12
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Learning Space With NASA at Home
Explore space and science activities you can do with NASA at home. Watch video tutorials for making rockets, Mars rovers, Moon landers and more. Plus, find tips for learning at home!
Subject Varies
Grades K-12
Explore More
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Meet JPL Interns of Mars 2020
Read stories about interns helping prepare NASA's next Mars rover for its launch this summer.
Grades
Time
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NASA #CountdownToMars STEM Toolkit
Explore links to activities, lessons, interactives, social media and more resources from NASA to participate in the Perseverance Mars rover mission.
- Website: Perseverance Mars Rover
- Website: NASA Mars Exploration
- Website: Space Place - All About Mars
- Watch Online – Virtual Events
TAGS: Mars, Mars 2020, Perseverance, Mars Rover, launch, Teach, teachers, educators, parents, lessons, activities, resources, K-12, STEM, events, students, science, engineering
Teachable Moments | May 6, 2016
A Teachable Moment You Can See! The Transit of Mercury
UPDATE - May 9, 2016: NASA's Solar Dynamics Observatory, or SDO, spacecraft captured stunning images of the May 9, 2016 transit of Mercury. Visit the mission's Transit of Mercury page to see a collection of videos of the transit compiled using SDO images. And have students play "Can You Spot Mercury?" in our educational slideshow.
In the News
It only happens about 13 times per century and hasn’t happened in nearly a decade, but on Monday, May 9, Mercury will transit the sun. A transit happens when a planet crosses in front of a star. From our perspective on Earth, we only ever see two planets transit the sun: Mercury and Venus. (Transits of Venus are even more rare. The next one won't happen until 2117!) On May 9, as Mercury passes in front of the sun, viewers around Earth (using the proper safety equipment) will be able to see a tiny dark spot moving slowly across the disk of the sun.
CAUTION: Looking directly at the sun can cause permanent vision damage – see below for tips on how to safely view the transit.
Why It's Important
Then and Now
In the early 1600s, Johannes Kepler discovered that both Mercury and Venus would transit the sun in 1631. It was fortunate timing: The telescope had been invented just 23 years earlier and the transits wouldn’t happen in the same year again until 13425. Kepler didn’t survive to see the transits, but French astronomer Pierre Gassendi became the first person to see the transit of Mercury (the transit of Venus wasn’t visible from Europe). It was soon understood that transits could be used as an opportunity to measure the apparent diameter – how large a planet appears from Earth – with great accuracy.
In 1677, Edmond Halley observed the transit of Mercury and realized that the parallax shift of the planet – the variation in Mercury’s apparent position against the disk of the sun as seen by observers at distant points on Earth – could be used to accurately measure the distance between the sun and Earth, which wasn’t known at the time.
Today, radar is used to measure the distance between Earth and the sun with greater precision than can be found using transit observations, but the transit of Mercury still provides scientists with opportunities for scientific investigation in two important areas: exospheres and exoplanets.
Exosphere Science
Some objects, like the moon and Mercury, were originally thought to have no atmosphere. But scientists have discovered that these bodies are actually surrounded in an ultra-thin atmosphere of gases called an exosphere. Scientists want to better understand the composition and density of the gases that make up Mercury’s exosphere and transits make that possible.
“When Mercury is in front of the sun, we can study the exosphere close to the planet,” said NASA scientist Rosemary Killen. “Sodium in the exosphere absorbs and re-emits a yellow-orange color from sunlight, and by measuring that absorption, we can learn about the density of gas there.”
![Mercury transits the sun in 2006](http://www.jpl.nasa.gov/edu/images/news/transit_mercury-2006.jpg)
Exoplanet Discoveries
When Mercury transits the sun, it causes a slight dip in the sun’s brightness as it blocks a tiny portion of the sun's light. Scientists discovered they could use that phenomenon to search for planets orbiting distant stars, called exoplanets, that are otherwise obscured from view by the light of the star. When measuring the brightness of far-off stars, a slight recurring dip in the light curve (a graph of light intensity) could indicate an exoplanet orbiting and transiting its star. NASA’s Kepler mission has found more than 1,000 exoplanets by looking for this telltale drop in brightness.
![illustration of how transits are used to find exoplanets](http://www.jpl.nasa.gov/edu/images/news/lightcurve_diagram.jpg)
Additionally, scientists have begun exploring the exospheres of exoplanets. By observing the spectra of the light that passes through an exosphere – similar to how we study Mercury’s exosphere – scientists are beginning to understand the evolution of exoplanet atmospheres as well as the influence of stellar wind and magnetic fields.
Watch It
Mercury will appear as a tiny dot on the sun’s surface and will require a telescope or binoculars with a special solar filter to see. Looking at the sun directly or through a telescope without proper protection can lead to serious and permanent vision damage. Do not look directly at the sun without a solar filter.
The transit of Mercury will begin at 4:12 a.m. PDT, meaning by the time the sun rises on the West Coast, Mercury will have been transiting the sun for nearly two hours. Fortunately, it will take seven and a half hours for Mercury to completely cross the sun’s face, so there will be plenty of time for West Coast viewers to witness this event. See the transit map to learn when and where the transit will be visible.
Don’t have access to a telescope, binoculars or a solar filter? Visit the Night Sky Network website for the location of events near you where amateur astronomers will have viewing opportunities available.
NASA also will stream a live program on NASA TV and the agency’s Facebook page from 7:30 to 8:30 a.m. PDT (10:30 to 11:30 a.m. EDT) -- an informal roundtable during which experts representing planetary, heliophysics and astrophysics will discuss the science behind the Mercury transit. Viewers can ask questions via Facebook and Twitter using #AskNASA.
Teach It
Here are two ways to turn the transit of Mercury into a lesson for students.
- Exploring Exoplanets with Kepler - Students use math concepts related to transits to discover real-world data about Mercury, Venus and planets outside our solar system.
- Pi in the Sky 3 - Try the "Sun Screen" problem on this illustrated math problem set that has students calculate the percentage drop in sunlight reaching Earth when Mercury transits.
Explore More
Transit Resources:
- NASA TV (live transit coverage)
- Night Sky Network Events
- Video: What’s Up – May 2016
- Transit Map
- What's a Transit?
- NASA Museum Alliance Resources
Exoplanet Resources:
- Kepler Mission Website
- Exoplanet Exploration Website
- Eyes on Exoplanets Interactive
- Transit Method for Detecting Exoplanets
- Exoplanet Travel Bureau Posters
- Video: What’s in an Exoplanet Name?
- Video: The Search for Another Earth
TAGS: Transit, Transit of Mercury, Mercury, Venus, Sun, Exoplanets, Teach, Classroom Activities, Lessons,