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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
Hubble Space Telescope Hubble Home Overview About Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & Benefits Hubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts Science Hubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts News Hubble News Hubble News Archive Social Media Media Resources Multimedia Multimedia Images Videos Sonifications Podcasts e-Books Online Activities Lithographs Fact Sheets Glossary Posters Hubble on the NASA App More 35th Anniversary 4 Min Read Hubble Reveals Surprising Spiral Shape of Galaxy Hosting Young Jet
Quasar J0742+2704 Credits:
NASA, ESA, Kristina Nyland (U.S. Naval Research Laboratory); Image Processing: Joseph DePasquale (STScI) The night sky has always played a crucial role in navigation, from early ocean crossings to modern GPS. Besides stars, the United States Navy uses quasars as beacons. Quasars are distant galaxies with supermassive black holes, surrounded by brilliantly hot disks of swirling gas that can blast off jets of material. Following up on the groundbreaking 2020 discovery of newborn jets in a number of quasars, aspiring naval officer Olivia Achenbach of the United States Naval Academy has used NASA’s Hubble Space Telescope to reveal surprising properties of one of them, quasar J0742+2704.
“The biggest surprise was seeing the distinct spiral shape in the Hubble Space Telescope images. At first I was worried I had made an error,” said Achenbach, who made the discovery during the course of a four-week internship.
Quasar J0742+2704 (center) became the subject of astronomers’ interest after it was discovered to have a newborn jet blasting from the disk around its supermassive black hole in 2020, using the Karl G. Jansky Very Large Array (VLA) radio observatory. This led to follow-up with other observatories in an effort to determine the properties of the galaxy and what may have triggered the jet. While the jet itself cannot be seen in this Hubble Space Telescope infrared-light image, the spiral shape of J0742+2704 is clear, with faint but detectable arms branching above and below the galaxy center. This was a big surprise to the research team, as quasars hosting jets are typically elliptical-shaped, and its suspected that messy mergers with other galaxies are what funnel gas toward the black hole and fuel jets. These mergers would also disrupt any spiral formation a galaxy may have had before mixing its contents with another galaxy. Though its intact spiral shape means it has not experienced a major merger, Hubble does show evidence that its lower arm has been disrupted, possibly by the tidal forces of interaction with another galaxy. This could mean that jets can be triggered by a far less involved, dramatic interaction of galaxies than a full merger. The large galaxy to the lower right of the quasar appears to be a ring galaxy, another sign of interaction. Some ring galaxies form after a small galaxy passes through the center of a larger galaxy, reconfiguring its gas and dust. The brightest parts of this image — foreground stars and the bright center of the quasar — show the characteristic “starry” spikes produced by Hubble (and other telescopes’) interior structure. They are not actual aspects of the cosmic objects. NASA, ESA, Kristina Nyland (U.S. Naval Research Laboratory); Image Processing: Joseph DePasquale (STScI) “We typically see quasars as older galaxies that have grown very massive, along with their central black holes, after going through messy mergers and have come out with an elliptical shape,” said astronomer Kristina Nyland of the Naval Research Laboratory, Achenbach’s adviser on the research.
“It’s extremely rare and exciting to find a quasar-hosting galaxy with spiral arms and a black hole that is more than 400 million times the mass of the Sun — which is pretty big — plus young jets that weren’t detectable 20 years ago,” Nyland said.
The unusual quasar takes its place amid an active debate in the astronomy community over what triggers quasar jets, which can be significant in the evolution of galaxies, as the jets can suppress star formation. Some astronomers suspect that quasar jets are triggered by major galaxy mergers, as the material from two or more galaxies mashes together, and heated gas is funneled toward merged black holes. Spiral galaxy quasars like J0742+2704, however, suggest that there may be other pathways for jet formation.
While J0742+2704 has maintained its spiral shape, the Hubble image does show intriguing signs of its potential interaction with other galaxies. One of its arms shows distortion, possibly a tidal tail.
Hubble captured intriguing hints of interaction, if not full merging, between galaxies including quasar J0742+2704. There is evidence of a distorted tidal tail, or a streamer of gas, that has been pulled out by the gravity of a nearby galaxy. The presence of a ring galaxy also suggests interaction: The distinctive shape of ring galaxies are thought to form when one galaxy passes through another, redistributing its contents into a central core circled by stars and gas. Astronomers will be doing further analysis of Hubble’s detailed spectroscopic data, plus follow-up with other telescopes that can see different types of light, to confirm the distances of the galaxies and how they may be affecting one another. NASA, ESA, Kristina Nyland (U.S. Naval Research Laboratory); Image Processing: Joseph DePasquale (STScI) “Clearly there is something interesting going on. While the quasar has not experienced a major disruptive merger, it may be interacting with another galaxy, which is gravitationally tugging at its spiral arm,” said Nyland.
Another galaxy that appears nearby in the Hubble image (though its location still needs to be spectroscopically confirmed) has a ring structure. This rare shape can occur after a galaxy interaction in which a smaller galaxy punches through the center of a spiral galaxy. “The ring galaxy near the quasar host galaxy could be an intriguing clue as to what is happening in this system. We may be witnessing the aftermath of the interaction that triggered this young quasar jet,” said Nyland.
Both Achenbach and Nyland emphasize that this intriguing discovery is really a new starting point, and there will be additional multi-wavelength analysis of J0742+2704 with data from NASA’s Chandra X-ray Observatory and the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. It’s also a case for keeping our eyes on the skies, said Achenbach.
“If we looked at this galaxy 20 years, or maybe even a decade ago, we would have seen a fairly average quasar and never known it would eventually be home to newborn jets,” said Achenbach. “It goes to show that if you keep searching, you can find something remarkable that you never expected, and it can send you in a whole new direction of discovery.”
The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
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Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Media Contact:
Claire Andreoli (claire.andreoli@nasa.gov)
NASA’s Goddard Space Flight Center, Greenbelt, MD
Leah Ramsay, Ray Villard
Space Telescope Science Institute, Baltimore, MD
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Last Updated Jan 13, 2025 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
Active Galaxies Astrophysics Astrophysics Division Goddard Space Flight Center Hubble Space Telescope Quasars Keep Exploring Discover More Topics From NASA
Hubble Space Telescope
Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.
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By European Space Agency
On 8 January 2025, the ESA/JAXA BepiColombo mission flew past Mercury for the sixth time, successfully completing the final ‘gravity assist manoeuvre’ needed to steer it into orbit around the planet in late 2026. The spacecraft flew just a few hundred kilometres above the planet's north pole. Close-up images expose possibly icy craters whose floors are in permanent shadow, and the vast sunlit northern plains.
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By European Space Agency
Video: 00:01:14 At the start of this new year, we look back at close-up pictures and solar flare data recorded by the ESA-led Solar Orbiter mission over the last three years. See and hear for yourself how the number of flares and their intensity increase, a clear sign of the Sun approaching the peak of the 11-year solar cycle.
This video combines ultraviolet images of the Sun's outer atmosphere (the corona, yellow) taken by Solar Orbiter's Extreme Ultraviolet Imager (EUI) instrument, with the size and locations of solar flares (blue circles) as recorded by the Spectrometer/Telescope for Imaging X-rays (STIX) instrument. The accompanying audio is a sonification based on the detected flares and the spacecraft's distance to the Sun.
Solar Orbiter moves on an elliptical path around the Sun, making a close approach to our star every six months. We can see this in the video from the spacecraft's perspective, with the Sun moving closer and farther over the course of each year. In the sonification, this is represented by the low background humming that loudens as the Sun gets closer and becomes quieter as it moves further away. (There are some abrupt shifts in distance visible in the video, as it skips over dates where one or both instruments were inactive or collecting a different type of data.)
The blue circles represent solar flares: bursts of high-energy radiation of which STIX detects the X-rays. Flares are sent out by the Sun when energy stored in 'twisted' magnetic fields (usually above sunspots) is suddenly released. The size of each circle indicates how strong the flare is, with stronger flares sending out more X-rays. We can hear the flares in the metallic clinks in the sonification, where the sharpness of the sound corresponds to how energetic the solar flare is.
Many thanks to Klaus Nielsen (DTU Space / Maple Pools) for making the sonification in this video. If you would like to hear more sonifications and music by this artist, please visit: https://linktr.ee/maplepools
Solar Orbiter is a space mission of international collaboration between ESA and NASA, operated by ESA.
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By NASA
3 min read
January’s Night Sky Notes: The Red Planet
by Kat Troche of the Astronomical Society of the Pacific
Have you looked up at the night sky this season and noticed a bright object sporting a reddish hue to the left of Orion? This is none other than the planet Mars! January will be an excellent opportunity to spot this planet and some of its details with a medium-sized telescope. Be sure to catch these three events this month.
Martian Retrograde
Mars entered retrograde (or backward movement relative to its usual direction) on December 7, 2024, and will continue throughout January into February 23, 2025. You can track the planet’s progress by sketching or photographing Mars’ position relative to nearby stars. Be consistent with your observations, taking them every few nights or so as the weather permits. You can use free software like Stellarium or Stellarium Web (the browser version) to help you navigate the night as Mars treks around the sky. You can find Mars above the eastern horizon after 8:00 PM local time.
This mid-January chart shows the path of Mars from September 2024 to June 2025 as it enters and then exits in retrograde motion. Mars appears to change its direction of motion in the sky because Earth is passing the slower-moving Mars in its orbit. Stellarium Hide and Seek
On the night of January 13th, you can watch Mars ‘disappear’ behind the Moon during an occultation. An occultation is when one celestial object passes directly in front of another, hiding the background object from view. This can happen with planets and stars in our night sky, depending on the orbit of an object and where you are on Earth, similar to eclipses.
A simulated view of the Moon as Mars begins its occultation on January 13, 2025. Stellarium Depending on where you are within the contiguous United States, you can watch this event with the naked eye, binoculars, or a small telescope. The occultation will happen for over an hour in some parts of the US. You can use websites like Stellarium Web or the Astronomical League’s ‘Moon Occults Mars’ chart to calculate the best time to see this event.
Closer and Closer
As you observe Mars this month to track its retrograde movement, you will notice that it will increase in brightness. This is because Mars will reach opposition by the evening of January 16th. Opposition happens when a planet is directly opposite the Sun, as seen from Earth. You don’t need to be in any specific city to observe this event; you only need clear skies to observe that it gets brighter. It’s also when Mars is closest to Earth, so you’ll see more details in a telescope.
Want a quick and easy way to illustrate what opposition is for Jupiter, Saturn, Mars, or other outer worlds? Follow the instructions on our Toolkit Hack: Illustrating Opposition with Exploring the Solar System page using our Exploring Our Solar System activity!
A mosaic of the Valles Marineris hemisphere of Mars projected into point perspective, a view similar to that which one would see from a spacecraft. The mosaic is composed of 102 Viking Orbiter images of Mars. NASA/JPL-Caltech Mars has fascinated humanity for centuries, with its earliest recorded observations dating back to the Bronze Age. By the 17th century, astronomers were able to identify features of the Martian surface, such as its ice caps and darker regions. Since the 1960s, exploration of the Red Planet has intensified with robotic missions from various space organizations. Currently, NASA has five active missions, including rovers and orbiters, with the future focused on human exploration and habitation. Mars will always fill us with a sense of wonder and adventure as we reach for its soil through initiatives such as the Moon to Mars Architecture and the Mars Sample Return campaign.
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