The Milky Way has been one of the fascinating objects present in our universe. The images of the Milky Way build curiosity to know more about the universe. And, Gaia telescope has added more beauty in the images after mapping the stars in the Milky Way. Gaia space observatory is tracking more than 1 billion stars in the galaxy. It has provided a static image and a picture of how stars will look in the future. Scientists in the ESA believe that the image will help them understand the universe’s evolution better.
What is the Gaia telescope?
Gaia is an ambitious mission launched in the year 2013 by the European Space Agency (ESA). The mission’s objective is to design and extrapolate the largest and most precise three-dimensional map of our galaxy, the Milky Way. Also, it has to understand the composition, formation, and evolution of the galaxy during the process. Gaia has to survey about 1% of the galaxy’s 100 billion stars. Gaia will detect and accurately measure each star’s motion in its orbit around the center of the galaxy. Each of these 1 billion stars that Gaia observatory will study at an average of 70 times over five years. As a result, it will record the brightness and position of each star. Hence, Gaia will provide high-quality measurements to deliver a stereoscopic and kinematic census of about 1 billion stars in our galaxy. It has set itself in the Sun-Earth L2 Lagrange point. The scientific instruments present in the Gaia telescope are:
- Astrometric instrument (ASTRO)
- Photometric instrument
- Radial velocity spectrometer (RVS)
About Milky Way
It is the galaxy present in our solar system. As the name suggests, it gives the appearance of a hazy band of light seen in the night sky. Famous astronomer Galileo Galilei discovered the presence of the Milky Way galaxy in the year 1610. The barred spiral galaxy has an estimated visible diameter of 1.9 million light-years. It has a low surface brightness. The Milky Way’s visibility reduces due to light pollution or moonlight. The entire galaxy has more than 100 billion stars and almost the same number of planets in it. It also may contain millions and billions of white dwarfs, neutron stars, and stellar black holes. There are two major arms (Scutum-Centaurus and Perseus) and two minor arms (Norma and Sagittarius) present in the Milky Way galaxy. The major arms are attached to the galaxy’s thick central bar’s ends, while the two minor arms are less distinct and located between the major arms. The highest densities of both young and old stars are in the major arms. In contrast, gasses in star-forming activity are present in the minor arms.
Observations of Gaia Telescope
The latest data collection improves the two previous Gaia data sets’ precision and scope, released during 2016 and 2018. Gaia’s latest update consists of 1.3 TB data against the 551 GB of the previous. The entire research spans around three years of data collection. Datasets obtained from the Gaia telescope have expanded its catalog of stars by 15% to 1.8 billion, and its measurements have become more precise. Compared with 2018, Gaia’s distance measurements are 50% better, along with 100% betterment in the study of stellar velocities.
Challenges During the Measurement
During the Gaia mission, the team research faced an unexpected issue with the probe. When the spacecraft spins, the sunlight falls on it at varying angles. As a result, there is a deformation in the shape of the spacecraft. This deformation has affected the earlier measurements about the stellar positions more than expected. However, the team has learned how to rectify the issues that arise from this effect. It means that for stars up to nearly 5,000 parsecs (16,000 light-years) of the Solar System, it can measure distances with 10% accuracy. By the time the mission finishes its objectives, the team expects that accuracy will reach 10,000 parsecs (twice the current measurement), as per the original plan.
Conclusion
Gaia’s detailed measurement of stellar motions empowers the researchers’ prediction of what Earth’s night sky will look like in the next 1.6 million years. A bigger dataset will publish in 2022 and include updated stellar spectra. The data set in 2022 will bring humanity closer to get the 3D map of our galaxy. It can also show thousands of stars wobbling under another object’s gravitational pull. Hence, it may provide a new tool to discover exoplanets. Gaia’s report is very concrete to lay down a consolidated study of the evolution of the universe.
