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By NASA
5 Min Read Planetary Alignments and Planet Parades
A sky chart showing Mars, Jupiter, Saturn, and Venus in a “planet parade.” Credits:
NASA/JPL-Caltech On most nights, weather permitting, you can spot at least one bright planet in the night sky. While two or three planets are commonly visible in the hours around sunset, occasionally four or five bright planets can be seen simultaneously with the naked eye. These events, often called “planet parades” or “planetary alignments,” can generate significant public interest. Though not exceedingly rare, they’re worth observing since they don’t happen every year.
Why Planets Appear Along a Line in The Sky
“Planet parade” isn’t a technical term in astronomy, and “planetary alignment” can refer to several different phenomena. As the planets of our solar system orbit the Sun, they occasionally line up in space in events called oppositions and conjunctions. A planetary alignment can also refer to apparent lineups in our sky with other planets, the Moon, or bright stars.
The planets of our solar system always appear along a line on the sky. This line, referred to as the ecliptic, represents the plane in which the planets orbit, seen from our position within the plane itself. NASA/Preston Dyches When it comes to this second type of planetary alignment, it’s important to understand that planets always appear along a line or arc across the sky. This occurs because the planets orbit our Sun in a relatively flat, disc-shaped plane. From Earth, we’re looking into that solar system plane from within. We see the racetrack of the planets from the perspective of one of the racers ourselves. When viewed edge-on, this disc appears as a line, which we call the ecliptic or ecliptic plane.
So, while planet alignment itself isn’t unusual, what makes these events special is the opportunity to observe multiple planets simultaneously with the naked eye.
Will the Planets Actually be Visible?
Before preparing to observe a planet parade, we have to consider how high the planets will appear above the horizon. For most observers to see a planet with the naked eye, it needs to be at least a few degrees above the horizon, and10 degrees or higher is best. This is crucial because Earth’s atmosphere near the ground dims celestial objects as they rise or set. Even bright planets become difficult or impossible to spot when they’re too low, as their light gets scattered and absorbed on its path to your eye. Buildings, trees, and other obstructions often block the view near the horizon as well.
This visibility challenge is particularly notable after sunset or before sunrise, where the sky is still glowing. If a planet appears very low within the sunset glow, it is very difficult to observe.
The Planets You Can See, and Those You Can’t
Five planets are visible without optical aid: Mercury, Venus, Mars, Jupiter, and Saturn. Ancient civilizations recognized these worlds as bright lights that wandered across the starscape, while the background stars remained fixed in place. In fact, the word “planet” comes to us from the Greek word for “wanderer.”
The solar system includes two additional major planets, Uranus and Neptune, plus numerous dwarf planets like Pluto and Ceres. Uranus and Neptune orbit in the dim, cold depths of the outer solar system. Neptune absolutely requires a telescope to observe. While Uranus is technically bright enough to detect with good eyesight, it’s quite faint and requires dark skies and precise knowledge of its location among similarly faint stars, so a telescope is recommended. As we’ll discuss in the next section, planet parades necessarily must be observed in twilight before dawn or after sunset, and this is not a good time to try observing extremely faint objects like Uranus and Neptune.
Thus, claims about rare six- or seven-planet alignments which include Uranus and Neptune should be viewed with the understanding that these two distant planets will not be visible to the unaided eye.
What Makes Multi-Planet Lineups Special
Lineups of four or five planet naked-eye planets with optimal visibility typically occur every few years. Mars, Jupiter, and Saturn are frequently seen in the night sky, but the addition of Venus and Mercury make four- and five-planet lineups particularly noteworthy. Both orbit closer to the Sun than Earth, with smaller, faster orbits than the other planets. Venus is visible for only a couple of months at a time when it reaches its greatest separation from the Sun (called elongation), appearing just after sunset or before sunrise. Mercury, completing its orbit in just 88 days, is visible for only a couple of weeks (or even a few days) at a time just after sunset or just before sunrise.
Planet parades aren’t single-day events, as the planets move too slowly for that. Generally, multi-planet viewing opportunities last for weeks to a month or more. Even five-planet events last for several days as Mercury briefly emerges from and returns to the Sun’s glare.
In summary, while they aren’t once-in-a-lifetime events, planetary parades afford an uncommon opportunity to look up and appreciate our place in our solar system, with diverse worlds arrayed across the sky before our very eyes.
Other Planet Lineups
Other recent and near-future multi-planet viewing opportunities:
January 2016 – Four planets visible at once before sunrise Late April to Late August 2022 – Four planets visible at once before sunrise Mid-June to Early July 2022 – Five planets visible at once before sunrise January to mid-February 2025 – Four planets visible at once after sunset Late August 2025 – Four planets visible at once before sunrise Late October 2028 – Five planets visible at once before sunrise Late February 2034 – Five planets visible at once after sunset (Venus and Mercury challenging to observe) About the January/February 2025 Planet Parade
The current four-planet lineup concludes by mid-February, as Saturn sinks increasingly lower in the sky each night after sunset. By mid-to-late February, Saturn appears less than 10 degrees above the horizon as sunset fades, making it difficult to observe for most people. While Mercury briefly joins Saturn in the post-sunset glow at the end of February, both planets will be too low and faint for most observers to spot.
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By NASA
1 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Artist concept highlighting the novel approach proposed by the 2025 NIAC awarded selection of PULSAR: Planetary pULSe-tAkeR concept.NASA/Marco Quadrelli Marco Quadrelli
NASA Jet Propulsion Laboratory
There is a strong coupling mechanism between the lithosphere, ionosphere, magnetosphere, atmosphere, and the plasmasphere of many planetary bodies. For example, the ionosphere has been shown to respond to space weather events induced by Solar activity, as well as to atmospheric events, and events in the surface and interior of a planet. PULSAR (Planetary pULSe-tAkeR) is a stable spacecraft constellation that enables large and reconfigurable detector baselines to sense a wide range of frequencies in this coupled domain, and distributed spatial and temporal measurements on a global scale, leading to new planetary science measurements. Like a doctor taking vitals and monitoring the health state of a patient, PULSAR literally “takes the pulse of the planet”.
2025 Selections
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Last Updated Jan 10, 2025 EditorLoura Hall Related Terms
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By NASA
Learn Home Science Activation NASA Workshops Culturally… Overview Learning Resources Science Activation Teams SME Map Opportunities More Science Activation Stories Citizen Science 2 min read
NASA Workshops Culturally Inclusive Planetary Engagement with Educators
From November 6-8, 2024, the NASA Science Activation Program’s Planetary Resources and Content Heroes (ReaCH) project held a Culturally Inclusive Planetary Engagement workshop at the Bradley Observatory at Agnes Scott College in Atlanta, Georgia for the space sciences community, including planetary science, astrobiology, astronomy, and heliophysics professionals, as well as invited education specialists. To practice the skills learned in the workshop, participants facilitated a variety of space-themed, culturally-inclusive, hands-on activities for 79 students, family, and staff at the Center for a New Generation at the Tuskegee Airmen Global Academy Boys and Girls Club.
Workshop participants provided anonymous feedback as a part of their workshop evaluations:
“[This experience] helped me learn a lot about how to make different cultures and ethnicities feel involved and included and also engage with them to inspire in them a love for science”
“. . .I feel like the discussions were so important to me, considering we all come from so many different backgrounds, and our exposure has been different, so we all have a different point of view to bring to the discussion that others, that I, might not think of right away. So I think it was really nice to hear so many different perspectives in all of these discussions.”
“[The facilitator] connected cultural diversity to an activity. That is not easy to do. I loved it and it is what I expected coming into this workshop.”
This workshop was conducted in partnership with Agnes Scott College, Georgia Tech, the Boys & Girls Clubs of Metro Atlanta, and members of the Center for Lunar Environment and Volatile Exploration Research (CLEVER) NASA Solar System Exploration Research Institute (SSERVI) Center. ReaCH workshops are designed to enhance the ability of scientists to engage their local communities in science. The Planetary ReaCH project is building a replicable model that will be used to support similar workshops for other science fields. NASA-funded researchers, including early-career scientists, are invited to apply for the 2025 workshops!
The Planetary ReaCH project is supported by NASA under cooperative agreement award number 80NSSC21M0003 and is part of NASA’s Science Activation Portfolio. Learn more about how Science Activation connects NASA science experts, real content, and experiences with community leaders to do science in ways that activate minds and promote deeper understanding of our world and beyond: https://science.nasa.gov/learn
The workshop was attended by researchers including early career scientists, planetary scientists, astrobiologists, astronomers, heliophysicists, and education specialists. Share
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Last Updated Jan 02, 2025 Editor NASA Science Editorial Team Related Terms
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By NASA
1 Min Read Coming Spring 2025: Planetary Defenders Documentary
David Rankin, Senior Survey Operations Specialist at Catalina Sky Survey, is seen opening the dome structure surrounding the telescope at the asteroid-hunting facility in Mt. Lemmon, AZ. Credits:
NASA How would humanity respond if we discovered an asteroid headed for Earth? NASA’s Planetary Defenders is a gripping documentary that delves into the high-stakes world of asteroid detection and planetary defense. Journey alongside a dedicated team of astronomers and scientists working tirelessly to track and monitor near-Earth asteroids, aiming to protect our planet from potential impacts. This documentary captures the intricate and collaborative efforts of these unsung heroes, blending cutting-edge science with personal stories to reveal the human spirit behind this critical global endeavor. Witness the drama, the challenges and the triumphs of those on the front lines of planetary defense.
The dinosaurs went extinct because they didn’t have a space program. We do have one.
Dr. vishnu reddy
Professor of Planetary Science, University of Arizona
Dr. Shantanu Naidu, Asteroid Radar Researcher, from NASA’s Jet Propulsion Laboratory points toward the Goldstone Solar System Radar in Barstow, CA – the most powerful planetary radar on Earth. NASA In 2016, NASA established the Planetary Defense Coordination Office (PDCO) to manage the agency’s ongoing mission of finding, tracking, and better understanding asteroids and comets that could pose an impact hazard to Earth.
I really like that I am protecting the planet. And yes, I’m not the one that’s with a cape pushing the asteroid away, that’s not what I do. In some ways, my little contribution might not help just myself, but someone in the future, and I think it’s very important to do that.
Dr. CASSANDRA LEJOLY
RESEARCHER, SPACEWATCH®
Dr. Cassandra Lejoly, a researcher with the University of Arizona’s SPACEWATCH® program, sits at a computer console at Kitt Peak National Observatory in Tuscon, AZ, where she conducts follow up observations on near-Earth objects. NASA Planetary Defenders is an original NASA documentary that showcases the challenges and the triumphs of those on the front lines of planetary defense. This documentary will be released on NASA+ and other streaming platforms in Spring 2025. Stay tuned for updates!
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Last Updated Dec 03, 2024 Related Terms
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