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Gaia’s map is a vast catalogue of measured stars and other objects—not a single photograph of the sky. ESA’s mission has recorded more than three trillion observations of two billion objects, measuring their positions and, for many, their distances, motions, brightness and other properties. Together, those measurements let astronomers build a three-dimensional—and in some cases six-dimensional—model of the Milky Way.
What is Gaia’s new sky map?
Gaia is a European Space Agency (ESA) astrometry mission: it repeatedly measures where objects appear in the sky and how those positions change. Its purpose is to determine the positions of nearly two billion objects and create what ESA calls “the largest and most precise 3D map of the Milky Way.” ESA’s Gaia mission page
That map is a scientific data set, not a conventional wide-field image. For stars, it can combine position with distance and movement through space. Gaia also records brightness and colour; its observations support estimates of properties such as temperature and composition. For some objects, radial velocity—the motion toward or away from us—is available too. With velocity information in three directions, astronomers can describe an object’s motion in six dimensions.
Gaia’s camera had nearly one billion pixels, but the mission’s defining achievement is not simply image resolution. It is the repeated, precise measurement of enormous numbers of objects, allowing researchers to reconstruct where stars are and how they move.
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How many stars and objects did Gaia map?
ESA’s current mission highlights report more than three trillion observations of two billion stars and other objects. The distinction matters: an observation is a measurement made at a particular time, while an object may be observed repeatedly. Those repeat measurements help Gaia determine motion and improve the reliability of its catalogue. ESA’s Gaia mission highlights
Gaia’s measurements reach objects far fainter than the unaided eye can see. ESA says that for objects 4,000 times fainter than the naked-eye limit, Gaia measured positions to 24 microarcseconds. A microarcsecond is one-millionth of an arcsecond, a unit of angular size. ESA also says the nearest stars’ distances will be measured to 0.001% accuracy. These are mission factsheet figures, not a claim that every object in the catalogue has the same positional or distance precision. ESA Gaia factsheet
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- This computer-generated image of the Milky Way shows the entire galaxy in one perspective of a 3-D model compiled specially for National Geographic.
- The model incorporates the positions of hundreds of thousands of stars and nebulae within the galaxy, shows Earth's location.
- Includes additional photographs, descriptions and locations of fascinating phenomena throughout the Milky Way.
- The map is encapsulated in heavy-duty 1.6 mil laminate which makes the paper much more durable and resistant to the swelling and shrinking caused by changes in humidity.
- Measures 31.25" x 20.25"
How Gaia’s map is being released
Gaia observed scientifically from 27 July 2014 through 15 January 2025. It is now retired from science operations while ESA and the Gaia Data Processing and Analysis Consortium process its measurements. Public catalogues have appeared in stages:
Do these 3 things before closing this tab:
1Clear out junk files and repair common Windows errors2Fix the driver behind crashes, sound loss and screen glitches3Repair Windows errors before they cause bigger problems| Release | Public release date |
|---|---|
| DR1 | 14 September 2016 |
| DR2 | 25 April 2018 |
| EDR3 | 3 December 2020 |
| DR3 | 13 June 2022 |
| Focused Product Release | 10 October 2023 |
ESA’s schedule lists Data Release 4 (DR4), based on 66 months of observations, as expected in December 2026. Data Release 5 (DR5), based on all mission data, is not expected before the end of 2030. These are planned dates and may change as processing and publication progress. ESA’s Gaia mission page
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- UNIQUE NATIONAL GEOGRAPHIC PRODUCT: This map offers a stunning look into the galaxy that we call home.
- CLASSY MAP FOR OFFICE OR HOME: The artistry in this beautiful product makes it a gorgeous addition to any collection!
- QUALITY PRINT: Printed on thick paper suitable for display on your home, school or office wall.
- ICONIC CARTOGRAPHY: National Geographic's maps are the standard others are measured against. You can count on this product having the highest quality content and display in the industry.
- TRUSTED CONTENT: National Geographic prides itself on the calibre and rigour of its editorial process so that you can count on having accurate information on every map
What Gaia has revealed about the Milky Way
Gaia’s catalogues let researchers test whether stars that look like a group in the sky actually share a common origin or motion. That has sharpened studies of star-cluster membership, ages and distances, as well as stellar streams, tidal tails, young stellar associations, molecular clouds and the Galaxy’s spiral structure. ESA reports that some star groups form connected chains, while other apparent groupings turn out to be chance alignments. ESA’s Gaia mission page
As Antonella Vallenari of Padova Astronomical Observatory, deputy chair of the Gaia Data Processing and Analysis Consortium, put it: “Thanks to Gaia, we can find and remove rogue stars that don’t actually belong to a cluster, making all of our science far more accurate.” ESA statement on Gaia
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- UNIQUE NATIONAL GEOGRAPHIC PRODUCT: This map offers a stunning look into the galaxy that we call home.
- CLASSY MAP FOR OFFICE OR HOME: The artistry in this beautiful product makes it a gorgeous addition to any collection!
- QUALITY PRINT: Printed on Polypropylene for rich clear colour and legibility. Makes for a beautiful product on your home, school or office wall.
- DURABLE MATERIAL: This quality print material won't easily crease or tear in shipping or with use
- ICONIC CARTOGRAPHY: National Geographic's maps are the standard others are measured against. You can count on this product having the highest quality content and display in the industry.
The measurements also contribute to a broader account of the Milky Way’s past. ESA’s factsheet describes evidence concerning the formation of the thick disc roughly 13 billion years ago and an ancient galaxy merger around 10 billion years ago, alongside research into stellar streams, hypervelocity stars, asteroids and exoplanets. These are scientific findings enabled or informed by Gaia data, rather than objects all directly imaged by the spacecraft. ESA Gaia factsheet
How to explore Gaia’s data
ESA makes Gaia data freely available through the Gaia Archive. It is a scientific archive for searching and working with catalogue data, rather than a single finished picture of the whole Galaxy. The archive’s expected scale is substantial: ESA’s factsheet says it is expected to exceed one petabyte by the end of the mission.
Gaia Project Scientist Johannes Sahlmann described the impact of the catalogues this way: “Gaia’s datasets are significantly more detailed and precise than any that have come before. It’s no exaggeration to say that the mission has brought about a revolution in Milky Way astronomy, especially when it comes to star clusters.” ESA statement on Gaia
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