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What’s Up - April 2018

What’s Up For April? 

The Moon, Mars and Saturn and the Lyrid meteor shower!

The Moon, Mars and Saturn

The Moon, Mars and Saturn form a pretty triangle in early April, the Lyrid Meteors are visible in late April, peaking high overhead on the 22nd.

You won't want to miss red Mars and golden Saturn in the south-southeast morning skies this month. Mars shines a little brighter than last month.

By the 7th, the Moon joins the pair. From a dark sky you may see some glow from the nearby Milky Way.

Lyrid Meteors

Midmonth, start looking for Lyrid meteors, which are active from April 14 through the 30th. They peak on the 22nd.

The Lyrids are one of the oldest known meteor showers and have been observed for 2,700 years. The first recorded sighting of a Lyrid meteor shower goes back to 687 BC by the Chinese. The pieces of space debris that interact with our atmosphere to create the Lyrids originate from comet C/1861 G1 Thatcher. Comet Thatcher was discovered on 5 April 1861 by A. E. Thatcher.

In the early morning sky, a patient observer will see up to more than a dozen meteors per hour in this medium-strength shower, with 18 meteors per hour calculated for the peak. U.S. observers should see good rates on the nights before and after this peak.

A bright first quarter moon plays havoc with sky conditions, marring most of the typically faint Lyrid meteors. But Lyra will be high overhead after the moon sets at midnight, so that's the best time to look for Lyrids.

Jupiter & Juno

Jupiter will also be visible in the night sky this month! 

Through a telescope, Jupiter's clouds belts and zones are easy to see. 

And watch the Great Red Spot transit--or cross--the visible (Earth-facing) disk of Jupiter every 8 hours.

Our Juno spacecraft continues to orbit this gas giant, too!

And Juno's JunoCam citizen science team is creating exciting images of Jupiter's features based on the latest spacecraft data.

Next month Jupiter is at opposition--when it rises at sunset, sets at sunrise, and offers great views for several months!

Watch the full What’s Up for April Video: 

There are so many sights to see in the sky. To stay informed, subscribe to our What’s Up video series on Facebook. Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.   

Was There Once Life On Mars?  Our Perseverance Rover Aims to Find Out

Our Perseverance mission is set to launch on Thursday, July 30 and could help answer many longstanding astrobiology questions about Mars. The mission will deliver our Perseverance rover to the Martian surface, and this powerful rover is equipped with a multitude of tools to study the planet's environment and to answer questions about whether or not the Red Planet could have had life in the past.

In preparation for launch, our Astrobiology Program is releasing a new update to Issue #2 of the graphic history series, Astrobiology: The Story of our Search for Life in the Universe. This new, fourth edition tells the tale of our exploration of Mars in relation to astrobiology.

The history of our exploration of Mars is full of struggle and triumph. Mars is a dangerous and difficult planet to visit, with frigid temperatures, damaging dust storms, low gravity, and a thin atmosphere. Despite the challenges, NASA missions have opened our eyes to a world that was much more Earth-like in its past, with environments that contained all the necessary conditions for life as we know it.

Issue #2 tells the complete history of our endeavours on Mars, from the Mariner missions to Viking and Pathfinder to Curiosity. In this fourth edition, you’ll find  details on the Perseverance rover and its journey to search for ancient signs and signatures of life that could once and for all tell us whether or not life gained a foothold on the ancient Red Planet.

Perseverance will also drill into Martian rocks and collect samples that will one day be returned to Earth by a future Mars Sample Return mission. The samples will be stored in special containers and carefully 'cached' in a location on Mars where they will be easily accessible for retrieval. These samples will allow astrobiologists to perform detailed experiments that robots are not yet able to undertake remotely.

Visit astrobiology.nasa.gov/graphic-histories/ to download the new edition of Astrobiology: The Story of our Search for Life in the Universe, and read the entire series to explore NASA’s astrobiology journey to understand the origin and evolution of life on Earth, and the potential for life elsewhere in the Universe!

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What is the most fascinating thing about black hole research for you, personally?

Solar System: Things to Know This Week

What's next for NASA? A quick look at some of the big things coming up:

1. We will add to our existing robotic fleet at the Red Planet with the InSight Mars lander set to study the planet's interior.

This terrestrial planet explorer will address one of the most fundamental issues of planetary and solar system science - understanding the processes that shaped the rocky planets of the inner solar system (including Earth) more than four billion years ago.

2. The Mars 2020 rover will look for signs of past microbial life, gather samples for potential future return to Earth.

The Mars 2020 mission takes the next step by not only seeking signs of habitable conditions on the Red Planet in the ancient past, but also searching for signs of past microbial life itself. The Mars 2020 rover introduces a drill that can collect core samples of the most promising rocks and soils and set them aside in a "cache" on the surface of Mars.

3. The James Webb Space Telescope will be the premier observatory of the next decade, studying the history of our Universe in infrared.

Webb will study every phase in the history of our Universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own solar system.

4. The Parker Solar Probe will "touch the Sun," traveling closer to the surface than any spacecraft before.

This spacecraft, about the size of a small car, will travel directly into the sun's atmosphere about 4 million miles from our star's surface. Parker Solar Probe and its four suites of instruments – studying magnetic and electric fields, energetic particles, and the solar wind – will be protected from the Sun’s enormous heat by a 4.5-inch-thick carbon-composite heat shield.

5. Our OSIRIS-REx spacecraft arrives at the near-Earth asteroid Bennu in August 2018, and will return a sample for study in 2023.

This mission will help scientists investigate how planets formed and how life began, as well as improve our understanding of asteroids that could impact Earth.

6. Launching in 2018, the Transiting Exoplanet Survey Satellite (TESS) will search for planets around 200,000 bright, nearby stars.

The Transiting Exoplanet Survey Satellite (TESS) is the next step in the search for planets outside of our solar system (exoplanets), including those that could support life. The mission will find exoplanets that periodically block part of the light from their host stars, events called transits.

7. A mission to Jupiter's ocean-bearing moon Europa is being planned for launch in the 2020s.

The mission will place a spacecraft in orbit around Jupiter in order to perform a detailed investigation of Europa -- a world that shows strong evidence for an ocean of liquid water beneath its icy crust and which could host conditions favorable for life.

8. We will launch our first integrated test flight of the Space Launch System rocket and Orion spacecraft, known as Exploration Mission-1.

The Space Launch System rocket will launch with Orion atop it. During Exploration Mission-1, Orion will venture thousands of miles beyond the moon during an approximately three week mission.

9. We are looking at what a flexible deep space gateway near the Moon could be.

We’ve issued a draft announcement seeking U.S. industry-led studies for an advanced solar electric propulsion (SEP) vehicle capability. The studies will help define required capabilities and reduce risk for the 50 kilowatt-class SEP needed for the agency’s near-term exploration goals.

10. Want to know more? Read the full story.

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10 Things: CubeSats — Going Farther

Now that the MarCOs — a pair of briefcase-sized interplanetary CubeSats — seem to have reached their limit far beyond Mars, we’re looking forward to an expanding era of small, versatile and powerful space-based science machines.

Here are ten ways we’re pushing the limits of miniaturized technology to see  just how far it can take us.

1. MarCO: The Farthest (So Far)

MarCO, short for Mars Cube One, was the first interplanetary mission to use a class of mini-spacecraft called CubeSats.

The MarCOs — nicknamed EVE and WALL-E, after characters from a Pixar film — served as communications relays during InSight's November 2018 Mars landing, beaming back data at each stage of its descent to the Martian surface in near-real time, along with InSight's first image.

WALL-E sent back stunning images of Mars as well, while EVE performed some simple radio science.

All of this was achieved with experimental technology that cost a fraction of what most space missions do: $18.5 million provided by NASA's Jet Propulsion Laboratory in Pasadena, California, which built the CubeSats.

WALL-E was last heard from on Dec. 29; EVE, on Jan. 4. Based on trajectory calculations, WALL-E is currently more than 1 million miles (1.6 million kilometers) past Mars; EVE is farther, almost 2 million miles (3.2 million kilometers) past Mars.

MarCO-B took these images as it approached Mars in November 2018. Credit: NASA/JPL-Caltech

2. What Are CubeSats?

CubeSats were pioneered by California Polytechnic State University in 1999 and quickly became popular tools for students seeking to learn all aspects of spacecraft design and development.

Today, they are opening up space research to public and private entities like never before. With off-the-shelf parts and a compact size that allows them to hitch a ride with other missions — they can, for example, be ejected from the International Space Station, up to six at a time — CubeSats have slashed the cost of satellite development, opening up doors to test new instruments as well as to create constellations of satellites working together.

CubeSats can be flown in swarms, capturing simultaneous, multipoint measurements with identical instruments across a large area. Sampling entire physical systems in this way would drive forward our ability to understand the space environment around us, in the same way multiple weather sensors help us understand global weather systems.

Ready to get started? Check out NASA’s CubeSats 101 Guide.

Engineer Joel Steinkraus uses sunlight to test the solar arrays on one of the Mars Cube One (MarCO) spacecraft at NASA's Jet Propulsion Laboratory. Credit: NASA/JPL-Caltech

3. Measuring Up

The size and cost of spacecraft vary depending on the application; some are the size of a pint of ice cream while others, like the Hubble Space Telescope, are as big as a school bus.

Small spacecraft (SmallSats) generally have a mass less than 400 pounds (180 kilograms) and are about the size of a large kitchen fridge.

CubeSats are a class of nanosatellites that use a standard size and form factor.  The standard CubeSat size uses a "one unit" or "1U" measuring 10x10x10 centimeters (or about 4x4x4 inches) and is extendable to larger sizes: 1.5, 2, 3, 6, and even 12U.

The Sojourner rover (seen here on Mars in 1997) is an example of small technology that pioneered bigger things. Generations of larger rovers are being built on its success.

4. A Legacy of Small Pathfinders

Not unlike a CubeSat, NASA’s first spacecraft — Explorer 1 — was a small, rudimentary machine. It launched in 1958 and made the first discovery in outer space, the Van Allen radiation belts that surround Earth. It was the birth of the U.S. space program.

In 1997, a mini-rover named Sojourner rolled onto Mars, a trial run for more advanced rovers such as NASA's Spirit, Opportunity and Curiosity.

Innovation often begins with pathfinder technology, said Jakob Van Zyl, director of the Solar System Exploration Directorate at NASA's Jet Propulsion Laboratory. Once engineers prove something can be done, science missions follow.

5. Testing in Space

NASA is continually developing new technologies — technologies that are smaller than ever before, components that could improve our measurements, on-board data processing systems that streamline data retrievals, or new methods for gathering observations. Each new technology is thoroughly tested in a lab, sometimes on aircraft, or even at remote sites across the world. But the space environment is different than Earth. To know how something is going to operate in space, testing in space is the best option.

Sending something unproven to orbit has traditionally been a risky endeavor, but CubeSats have helped to change that. The diminutive satellites typically take less than two years to build. CubeSats are often a secondary payload on many rocket launches, greatly reducing cost. These hitchhikers can be deployed from a rocket or sent to the International Space Station and deployed from orbit.

Because of their quick development time and easy access to space, CubeSats have become the perfect platform for demonstrating how a new technological advancement will perform in orbit.

RainCube is a mini weather satellite, no bigger than a shoebox, that will measure storms. It’s part of several new NASA experiments to track storms from space with many small satellites, instead of individual, large ones. Credit: UCAR

6. At Work in Earth Orbit

A few recent examples from our home world:

RainCube, a satellite no bigger than a suitcase, is a prototype for a possible fleet of similar CubeSats  that could one day help monitor severe storms, lead to improving the accuracy of weather forecasts and track climate change over time.

IceCube tested instruments for their ability to make space-based measurements of the small, frozen crystals that make up ice clouds. Like other clouds, ice clouds affect Earth’s energy budget by either reflecting or absorbing the Sun’s energy and by affecting the emission of heat from Earth into space. Thus, ice clouds are key variables in weather and climate models.

Rocket Lab's Electron rocket lifts off from Launch Complex 1 for the NASA ELaNa19 mission. Credit: Trevor Mahlmann/Rocket Lab

7. First Dedicated CubeSat Launch

A series of new CubeSats is now in space, conducting a variety of scientific investigations and technology demonstrations following a Dec. 17, 2018 launch from New Zealand — the first time CubeSats have launched for NASA on a rocket designed specifically for small payloads.

This mission included 10 Educational Launch of Nanosatellites (ELaNa)-19 payloads, selected by NASA’s CubeSat Launch Initiative:

CubeSat Compact Radiation Belt Explorer (CeREs) — High energy particle measurement in Earth’s radiation belt

Simulation-to-Flight 1 (STF-1) — Software condensing to support CubeSat implementations

Advanced Electrical Bus (ALBus) — Advances in solar arrays and high capacity batteries

CubeSat Handling Of Multisystem Precision Time Transfer (CHOMPTT) — Navigation plans for exo-planetary implementation

CubeSail — Deployment and control of a solar sail blade

NMTSat — Magnetic field, high altitude plasma density

Rsat — Manipulation of robotic arms

Ionospheric Scintillation Explorer (ISX) — Plasma fluctuations in the upper atmosphere

Shields-1 — Radiation shielding

DaVinci — High School to Grade School STEM education

8. The Little CubeSat That Could

CubeSat technology is still in its infancy, with mission success rates hovering near 50 percent. So, a team of scientists and engineers set out on a quest. Their goal? To build a more resilient CubeSat — one that could handle the inevitable mishaps that bedevil any spacecraft, without going kaput.

They wanted a little CubeSat that could.

They got to work in 2014 and, after three years of development, Dellingr was ready to take flight.

Read the Full Story: Dellingr: The Little CubeSat That Could

Artist's concept of Lunar Flashlight. Credit: NASA

9. Going Farther

There are a handful of proposed NASA missions could take CubeSat technology farther:

CUVE would travel to Venus to investigate a longstanding mystery about the planet’s atmosphere using ultraviolet-sensitive instruments and a novel, carbon-nanotube light-gathering mirror.

Lunar Flashlight would use a laser to search for water ice in permanently shadowed craters on the south pole of Earth’s Moon.

Near-Earth Asteroid Scout, a SmallSat, would use a solar sail to propel it to do science on asteroids that pass close to Earth.

All three spacecraft would hitch rides to space with other missions, a key advantage of these compact science machines.

Expedition 56 Flight Engineer Serena Auñón-Chancellor installs the NanoRacks Cubesat Deployer-14 (NRCSD-14) on the Multipurpose Experiment Platform inside the Japanese Kibo laboratory module. The NRCSD-14 was then placed in the Kibo airlock and moved outside of the space station to deploy a variety of CubeSats into Earth orbit. Credit: NASA

10. And We’re Just Getting Started

Even if they're never revived, the team considers MarCO a spectacular success.

A number of the critical spare parts for each MarCO will be used in other CubeSat missions. That includes their experimental radios, antennas and propulsion systems. Several of these systems were provided by commercial vendors, making it easier for other CubeSats to use them as well.

More small spacecraft are on the way. NASA is set to launch a variety of new CubeSats in coming years.

"There's big potential in these small packages," said John Baker, the MarCO program manager at JPL. "CubeSats — part of a larger group of spacecraft called SmallSats — are a new platform for space exploration affordable to more than just government agencies."

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Special Celestial Events in June 2020

Earth and the Moon are in a constant dance as they orbit the Sun — and in June 2020, they’ll create two special celestial events. 

June 20: Summer solstice in the Northern Hemisphere 

Earth has a slight tilt as it orbits the Sun, and June is one of two times each year when that tilt is most prominent: a solstice. At the solstices, which happen each year in June and December, Earth’s tilt is at the greatest angle with respect to the plane of its orbit, meaning that one hemisphere is tilted towards the Sun, and the other hemisphere is tilted away. 

In the Northern Hemisphere, June 20 is the summer solstice — the Northern Hemisphere is tilted towards the Sun, so the June solstice is the day on which the Northern Hemisphere receives the longest stretch of daylight for the year.

In both hemispheres, the Sun will rise and set at its northernmost point on the horizon. After June 20, the Sun will appear to travel south.

This view from our Earth Polychromatic Imaging Camera on the National Oceanic and Atmospheric Administration's DSCOVR satellite shows the change in Earth’s tilt between the June and December solstices.

During the June solstice, the Southern Hemisphere is tilted away from the Sun, meaning the June solstice marks its shortest stretch of daylight for the year. June is the Southern Hemisphere’s winter solstice.  

June 21: Annular solar eclipse in Africa and Asia

The day after the solstice will see another special celestial event: an annular eclipse. Eclipses happen when the Moon lines up just right between the Sun and Earth, allowing it to block out part or all of the Sun’s bright face and cast a shadow on Earth. Though the Moon orbits Earth about once a month, its orbit is tilted by five degrees, so the perfect alignment that creates an eclipse is relatively rare. Often the Moon is too high or low in our sky to block out the Sun.

The June 21, 2020, eclipse is an annular eclipse visible primarily in Africa and Asia. During an annular eclipse, the Moon is too far from Earth and its apparent size is too small to entirely block out the face of the Sun, leaving a sliver of the Sun visible around the Moon’s edge during the eclipse and creating a “ring of fire” effect.

Credit: Dale Cruikshank

Outside the path of annularity, people in other parts of Africa, Asia and even some of Europe and the Pacific have a chance to see a partial solar eclipse, weather permitting. The degree of the partial eclipse depends on how close you are to the path of annularity. Locations far from the path of annularity will see only a small part of the Sun covered by the Moon, while places close to the path will see almost all of the Sun obscured.

No matter where you are, you must take safety precautions to watch the eclipse safely. There is no part of an annular eclipse during which it is safe to look directly at the Sun. You must use a proper solar filter or an indirect viewing method during all phases of the eclipse — even if only a tiny sliver of the Sun is visible around the Moon’s edge, that’s still enough to cause damage to your eyes.  

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Solar System: Things to Know This Week

For the first time in almost a decade, we're going back to Jupiter. Our Juno spacecraft arrives at the king of planets on the fourth of July. From a unique polar orbit, Juno will repeatedly dive between the planet and its intense belts of charged particle radiation. Juno's primary goal is to improve our understanding of Jupiter's formation and evolution, which will help us understand the history of our own solar system and provide new insight into how other planetary systems form.

In anticipation, here are a few things you need to know about the Juno mission and the mysterious world it will explore:

1. This is the Big One

The most massive planet in our solar system, with dozens of moons and an enormous magnetic field, Jupiter rules over a kind of miniature solar system.

2. Origin Story

Why study Jupiter in the first place? How does the planet fit into the solar system as a whole? What is it hiding? How will Juno unlock its secrets? A series of brief videos tells the stories of Jupiter and Juno. Watch them HERE.

3. Eyes on Juno

If you really want a hands-on understanding of Juno's flight through the Jupiter system, there's no better tool than the "Eyes on Juno" online simulation. It uses data from the mission to let you realistically see and interact with the spacecraft and its trajectory—in 3D and across both time and space.

4. You’re on JunoCam!

Did you know that you don't have to work for NASA to contribute to the Juno mission? Amateur astronomers and space enthusiasts everywhere are invited to help with JunoCam, the mission's color camera. You can upload your own images of Jupiter, comment on others' images, and vote on which pictures JunoCam will take when it reaches the Jovian system.

5. Ride Along

It's easy to follow events from the Juno mission as they unfold. Here are several ways to follow along online:

Twitter

Facebook

Instagram

Want to learn more? Read our full list of the 10 things to know this week about the solar system HERE.

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Let Us See Jupiter Through Your Eyes

Our Juno spacecraft will fly over Jupiter’s Great Red Spot on July 10 at 10:06 p.m. EDT. This will be humanity’s first up-close and personal view of the gas giant’s iconic 10,000-mile-wide storm, which has been monitored since 1830 and possibly existing for more than 350 years.

The data collection of the Great Red Spot is part of Juno’s sixth science flyby over Jupiter’s mysterious cloud tops. Perijove (the point at which an orbit comes closest to Jupiter’s center) will be July 10 at 9:55 p.m. EDT. 

At the time of perijove, Juno will be about 2,200 miles above the planet’s cloud tops. Eleven minutes and 33 seconds later…Juno will have covered another 24,713 miles and will be directly above the coiling crimson cloud tops of the Great Red Spot. The spacecraft will pass about 5,600 miles above its clouds. 

When will we see images from this flyby?

During the flyby, all eight of the spacecraft’s instruments will be turned on, as well as its imager, JunoCam. Because the spacecraft will be collecting data with its Microwave Radiometer (MWR), which measures radio waves from Jupiter’s deep atmosphere, we cannot downlink information during the pass. The MWR can tell us how much water there is and how material is moving far below the cloud tops.

During the pass, all data will be stored on-board…with a downlink planned afterwards. Once the downlink begins, engineering data from the spacecraft’s instruments will come to Earth first, followed by images from JunoCam.

The unprocessed, raw images will be located HERE, on approximately July 14. Follow @NASAJuno on Twitter for updates.

Did you know you can download and process these raw images?

We invite the public to act as a virtual imaging team…participating in key steps of the process, from identifying features of interest to sharing the finished images online. After JunoCam data arrives on Earth, members of the public can process the images to create color pictures. The public also helps determine which points on the planet will be photographed. Learn more about voting on JunoCam’s next target HERE.

JunoCam has four filters: red, green, blue and near-infrared. We get red, green and blue strips on one spacecraft rotation (the spacecraft rotation rate is 2 revolutions per minute) and the near-infrared strips on the second rotation. To get the final image product, the strips must be stitched together and the colors lined up.

Anything from cropping to color enhancing to collaging is fair game. Be creative!

Submit your images to Juno_outreach@jpl.nasa.gov to be featured on the Mission Juno website!

Check out some of these citizen-scientist processed images from previous Juno orbits: 

Credit: Sean Doran (More)

Credit: Amelia Carolina (More)

Credit: Michael Ranger (More)

Credit: Jason Major (More)

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This composite image shows a coronal mass ejection, a type of space weather linked to solar energetic particles, as seen from two space-based solar observatories and one ground-based instrument. The image in gold is from NASA’s Solar Dynamics Observatory, the image in blue is from the Manua Loa Solar Observatory’s K-Cor coronagraph, and the image in red is from ESA and NASA’s Solar and Heliospheric Observatory.

Our constantly-changing sun sometimes erupts with bursts of light, solar material, or ultra-fast energized particles — collectively, these events contribute to space weather. A new study shows that the warning signs of one type of space weather event can be detected tens of minutes earlier than with current forecasting techniques – critical extra time that could help protect astronauts in space. 

Credits: NASA/ESA/SOHO/SDO/Joy Ng and MLSO/K-Cor

How Well Do You Know Mercury?

Mercury is the smallest planet in our solar system and is only slightly larger than Earth’s moon. To give you some perspective, if the sun were as tall as a typical front door, Earth would be the size of a nickel and Mercury would be about as big as a green pea.

Mercury is the closest planet to the sun. Daytime temperatures can reach 430 degrees Celsius (800 degrees Fahrenheit) and drop to –180 degrees Celsius (-290 degrees Fahrenheit) at night.

Here are a few fun facts about Mercury:

Mercury takes only 88 Earth days to orbit the sun

If we could stand on Mercury’s surface when it is at its closest point to the sun, the sun would appear more than three times larger than it does here on Earth

Mercury is home to one of the largest impact basins in the solar system: the Caloris Basin. The diameter of this impact basin is the length of 16,404 football fields (minus the end zones) placed end to end!

Mercury is one of only two planets in our solar system that do not have moons (Venus is the other one)

Mercury completes three rotations for every two orbits around the sun. That means that if you wanted to stay up from sunrise to sunrise on Mercury, you’d be up for 176 Earth days…you’d need a LOT of coffee! 

Two missions have visited Mercury:

Mariner 10 was the first mission to Mercury, and 30 years later, our MESSENGER mission was the second to visit the planet. Mariner 10 was also the first spacecraft to reach one planet by using the gravity of another planet (in this case, Venus) to alter its speed and trajectory.

MESSENGER was the first spacecraft to orbit Mercury, The spacecraft had its own shades to protect it from the light of the sun. This is important since sunlight on Mercury can be as much as 11 times brighter than it is here on Earth. The spacecraft was originally planned to orbit Mercury for one year, but exceeded expectations and worked for over four years capturing extensive data. On April 30, 2015, the spacecraft succumbed to the pull of solar gravity and impacted Mercury’s surface.

Water Ice?

The MESSENGER spacecraft observed compelling support for the long-held hypothesis that Mercury harbors abundant water ice and other frozen volatile materials in its permanently shadowed polar craters.

This radar image of Mercury’s north polar region. The areas shown in red were captured by MESSENGER, compared to the yellow deposits imaged by Earth-based radar. These areas are believed to consist of water ice.

Mercury Transit of the Sun

For more than seven hours on Monday, May 9, Mercury will be visible as a tiny black dot crossing the face of the sun. This rare event – which happens only slightly more than once a decade – is called a transit.

Where: Skywatchers in Western Europe, South America and eastern North America will be able to see the entirety of the transit. The entire 7.5-hour path across the sun will be visible across the Eastern U.S. – with magnification and proper solar filters – while those in the West can observe the transit in progress at sunrise.

Watch: We will stream a live program on NASA TV and the agency’s Facebook page from 10:30 to 11:30 a.m. – 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. Unlike the 2012 Venus transit of the sun, Mercury is too small to be visible without magnification from a telescope or high-powered binoculars. Both must have safe solar filters made of specially-coated glass or Mylar; you can never look directly at the sun.

To learn more about our solar system and the planets, visit: http://solarsystem.nasa.gov/

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