New Milky Way Visualizations Show the Dance of Millions of Stars in Incredible Detail

The Gaia spacecraft has two telescopes on board, and it observes the Milky Way galaxy from an orbital perch called the Lagrange 2, or L2, point, located about 1 million miles (1.5 million kilometers) away from Earth (that’s the same orbit currently being used by NASA’s Webb Space Telescope).

The above visualization shows the Milky Way’s disc, which stretches about 100,000 light-years across. The rotation of the disc is illustrated through different colors, with darker shades indicating objects moving toward us and brighter shades indicating objects moving away. Meanwhile, there are some outliers that aren’t quite traveling with their surrounding group, which can be spotted as tiny dots in the crowd.

Correction: A previous version of this slide stated that the Milky Way disc is 10,000 light-years across, when actually it is 100,000 light-years wide.

Gazing out at the night sky, you may not be able to tell that stars are constantly in motion, orbiting the center of the galaxy. The speed at which stars are moving from our perspective on Earth is referred to as radial velocity, or the rate of change in distance between a target and its observer.

This map of the sky reveals the motion of approximately 26 million stars, with different colors indicating the velocities at which the stars are moving. Blue shows the parts of the sky where the average motion of stars is toward us, and red shows the regions where the average motion is away from us. The visualization reveals the circular motion of the stars around the center of the Milky Way, appearing as a perfectly combed sandbox of stellar inhabitants.

The galactic plane is not all stars. In between those luminous balls of gas are interstellar dust and clouds of gas, from which stars are born.

By measuring the positioning of stars and the light they emit, Gaia also captured the absorption of starlight by the interstellar medium, creating a map of the interstellar dust in the Milky Way. The darker blue areas in the visualization reveal more concentrated regions of dust, which fades into the yellow to indicate a fading amount of dust.

Stars are formed from clouds of gas and dust, which collapse under huge gravitational forces. The chemical composition of a star tells scientists about where it formed and how it ended up in its current position, thereby painting a better picture of the evolution of the galaxy over time.

Gaia’s data reveals what stars are made of. The reddish stars indicate that they are richer in metals, and therefore created later in the universe’s history. Elements heavier than iron are forged in supernovae, the explosive deaths of large stars.

Stars experience their own version of earthquakes, called starquakes. These stellar vibrations are movements of gas, making the stars sort of blink, or change their brightness over a time period that varies from seconds to weeks.

Although Gaia was not originally designed to detect starquakes, the observatory discovered more than 100,000 massive, hot blinking stars. These starquakes allow scientists to peer inside the stars, measuring their temperature, density, and rotation.

It wasn’t all stars for Gaia’s third dataset. The space observatory also mapped the orbit of more than 150,000 asteroids, from the inner parts of the solar system all the way out to the Trojan asteroids that trail behind, and lead in front of, Jupiter. The different types of asteroids are indicated by different colors.

The yellow dot at the center of the illustration is the Sun, while the blue represents the inner part of the solar system, with its rocky planets Mercury, Venus, Earth, and Mars, and Near Earth Asteroids, as well as Mars crossers. The main asteroid belt, which lies between Mars and Jupiter, is represented in green, while Jupiter’s Trojans are red.

Gaia also captured the positioning of the asteroids on June 13 at 12 pm CEST (6:00 a.m. EST). The tails show the movement of each asteroid over 10 days.

The inner bodies move faster around the Sun, which is why they are able to complete more of their orbits during that 10-day period.

The Milky Way stretches over 100,000 light-years across. Our solar system lies on the edge of the galaxy, giving us a limited view of our cosmic home.

Gaia has recorded billions of objects, but that represents a tiny fraction of the massive galaxy in which we reside. This final illustration shows the area mapped out by Gaia—an incredible feat, but still so limited. But Gaia will remain operational until at least 2025, hopefully providing scientists with many more valuable insights.