New data on the subject paints the most accurate picture of the Milky Way

1.6 billion stars. 11.4 million galaxies. 158,000 asteroids.

A spaceship.

The European Space Agency’s Theme Space Observatory, launched in 2013, has long surpassed its goal of drawing more than a billion stars on the Milky Way (SN: 15/10/16). On June 13, the mission expanded that map to new dimensions, releasing more accurate measurements of hundreds of millions of stars and, for the first time, asteroids, galaxies, and dust between stars.

“Suddenly you have a flood of data,” says Laurent Eyer, an astrophysicist at the University of Geneva who has worked on Gaia for years. For some astronomical subjects, the new results effectively replace all previous observations, Eyer says. “The data is better. It’s amazing. “

Data from a new survey collected from 2014 to 2017 are already making some discoveries, including the presence of extremely massive “star earthquakes” on the surfaces of thousands of stars.SN: 8/2/19). But more than anything, the release is a new tool for astronomers that will help them understand how stars, planets, and entire galaxies form and evolve.

Here are some old puzzles that can help you solve the data.

Asteroid mix

The asteroid belt between Mars and Jupiter is a mess of history. Once the Earth and other planets were completed, the remaining building blocks of stone were smashed against each other, leaving the tangled parts behind. But scientists know enough about individual asteroids to reconstruct when and where they come from. (SN: 19/4/13). And that can take a look at the early days of the solar system.

Using new data on the subject, astronomers drew the positions of 156,000 asteroids on June 13, 2022. The orbits show the orbits of the last 10 days, and the colors mark different groups of asteroids depending on their location (blue, the inner solar system; green, the main asteroid belt between Mars and Jupiter; orange, the Trojan asteroids near Jupiter).DPAC / Gaia / ESA, CC BY-SA 3.0 UP

Federica Spoto, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics in Cambridge (Mass), says that a large new set of data on the subject could help solve this puzzle. It collects data on the chemical composition of more than 60,000 asteroids, six times as much as the researchers found. before using other tools. This information may be essential for asteroids to return to their fragile origins.

“You can go back in time and try to understand the whole formation and evolution of the solar system,” says Spoto Gaia collaborator.That’s what we couldn’t even think of before Gaia. ‘

Asteroids are not just parts of the past, however; they are also dangerous. The new data could reveal asteroids that are almost impossible to detect from Earth because they orbit too close to the sun, says Thomas Burbine, a planetary scientist at Mount Holyoke College in South Hadley (Mass.), Who is not involved in the mission. (SN: 20/2/15). Since these asteroids originally came from farther afield (such as the asteroid belt), they could potentially indicate rocks passing through Earth that could potentially hit us. “We get to know our neighborhood better,” says Burbin.

Date with a star

It is difficult to measure the age of the stars (SN: 23/7/21). “It’s not uncommon to have more than a billion years of uncertainty,” says Alessandro Savino, an astrophysicist at the University of California, Berkeley, who is not involved with Gaia. Unlike brightness or location, age is not directly visible. Astronomers need to rely on theories about how stars evolve in order to predict their age according to what they can measure.

If past versions of the topic survey were like a photo of the stars, the newly released photo is like changing from black and white to color. It gives a deeper look at hundreds of millions of stars by measuring their temperature, gravity and chemistry. “You imagine the star is this point in space, but then they have a lot of properties,” Spot says. “That’s what the subject gives you.”

Although this type of measurement is not new, it has never been collected on such a scale on the Milky Way. This data can provide more information about how stars evolve. “We can improve the resolution of our watches,” Savino says.

Milky Way snacks

Although it seems unchanging, the Milky Way is talking about a stable diet for smaller galaxies; he’s eating right now too. But for decades, predictions of when and how these cosmic fusions occurred have contradicted the evidence in our galaxy, says Bertrand Goldman, an astrophysicist at the International Space University in Strasbourg, France, who is not involved in the release of Gaia data. “This has been controversial for a long time,” says Goldman, “but I think the issue will certainly be clarified.”

The key is to differentiate between the different structures of the Milky Way and how old they are (SN: 1/10/20). The latest version of the theme helps in two ways: by mapping the chemistry of stars and measuring their motion. Previous versions of the survey described how millions of stars moved, but mostly in two dimensions. The new catalog quadruples the number of stars in the entire 3D trajectory from 7 million to 33 million.

This has consequences outside of our neighborhood. Most of the mass in the universe is in galaxies like the Milky Way, so knowing how our galaxy works has a long way to go in understanding space on a larger scale. And the more scientists understand the parts of the galaxy that they can see, the more they will learn about dark matter, a mysterious substance that causes gravity but does not interact with light (SN: 6/25/21).

Even as astronomers pull out this latest set of data, they are already looking for the treasure of the future. The next round is a year away, but it is expected to allow thousands of exoplanets to be found, make rare measurements of black holes and help astronomers control how fast the universe is expanding. This is partly because Gaia is designed to track the movement of objects in space, which is easier as time goes on. So the observations of the Subject may be stronger. “Like good wine, they age very, very well,” says Savino.

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