Astronomers reveal most complete map of our galaxy

Astronomers reveal most complete map of our galaxy

*This article was written by a columnist tech world; Learn more at the end.

Earlier this week, the Gaia Survey released its latest survey of our night sky, the most complete census of stars, quasars, galaxies and other celestial objects released to date.

Gaia Mission

GAIA is a space telescope launched in 2013.The device monitors the entire sky and creates a survey with the main goal of building our best 3D map galaxyOne Milky WayWith this map, the mission will provide the positions of billions of stars with unprecedented accuracy.

In addition, we will obtain velocity information in 3 dimensions, allowing us to study objects and the galaxy itself in greater depth. By monitoring the sky, GAIA was able to capture changes in the brightness of some objects that could lead to the discovery of exoplanets.

Finally, the telescope will observe more than 500,000 distant quasars, providing essential new data for the continued development of Albert Einstein’s general theory of relativity.

Gaia MissionGaia MissionSource: ESA-GAIA

What is the ruler of the universe?

Measuring the distance of objects in the sky is not easy. Bright stars can be very large or very close, while faint stars can be very small or very far away. So how do you measure the distance to the stars without a ruler or going there?

The branch of measuring distance and position is called astrometry, and one of the most accurate techniques is called parallax. The principle of parallax is simple geometry and not difficult to understand. Reach out your hand, point your fingers in front of you, and close one eye at a time. Now, when you change your closed eyes, you can see a noticeable movement of your fingers. You can measure the distance to your fingers by knowing the distance between your eyes and nose and the size of your arm with simple geometry. This is the concept of parallax. But instead of your nose we see the sun, and each eye has the position of the earth at a time of year.

Illustrated Parallax ConceptIllustrated Parallax ConceptSource: ESA-GAIA

When looking at an object, we can map its position relative to the object in the background. After 6 months we will be on the other side of the sun (ie how to switch which eye is open) and we can go back to looking at the same object. We will notice a small change in the position of this object. With this variation, we are able to measure your distance!

But not everything is perfect. This technique works very well for objects at close range, and requires great precision for objects farther away, which is where the GAIA telescope comes in, with unprecedented precision! Nearby stars have apparent motion of an arcsecond. This mission will be able to accurately measure apparent motion down to 0.000001 arcseconds! For scale purposes, 1 arc second corresponds to 1/3600 of a degree, and the apparent size of the full moon in the sky is 2 degrees.

This is not an image of the Milky Way. There are millions of images together.Each point has detailed observations from the GAIA telescopeThis is not an image of the Milky Way. There are millions of images together.Each point has detailed observations from the GAIA telescopeSource: ESA-GAIA

Camila de Savretascolumnist tech world, holds a bachelor’s and master’s degree in astronomy. She is currently a PhD student at the European Southern Observatory (Germany). Self-proclaimed galactic coroner, investigating the evolution of galaxies and possible changes in star-making. He appears on social media as @astronomacamila.

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