ESO telescope captures the most detailed infrared map ever of our Milky Way | ESO
PR Image eso2413a
This Picture of the Week shows a new view of NGC 3603 (left) and NGC 3576 (right), two stunning nebulas imaged with ESO’s Visible and Infrared Survey Telescope for Astronomy (VISTA). This infrared image peers through the dust in these nebulas, revealing details hidden in optical images. NGC 3603 and NGC 3576 are 22,000 and 9,000 lightyears away from us, respectively. Inside these extended clouds of dust and gas, new stars are born, gradually changing the shapes of the nebulas via intense radiation and powerful winds of charged particles. Given their proximity, astronomers have the opportunity to study the intense star formation process that is as common in other galaxies but harder to observe due to the vast distances.
It's stretching credulity to breaking point to pretend the Bronze Age pastoralists knew full well how large and magnificent the Universe really is, with its countless trillions of galaxies each with half a trillion stars or more, but chose to describe it in some metaphorical way instead, complete with stars that shake loose from the dome and fall to earth during earthquakes. That's not allegorical; it's a mistake from assuming that meteorites burning up in the atmosphere were falling stars - an easy mistake to make if you know neither what stars are nor what meteorites are.
And like the description of meteorites, their description of the rest of it is based on guesses made from a position of ignorance, and an underlying assumption that somewhere up there above it all were magical, superhuman figures creating it all and making it work.
Tell me about the Milky Way Galaxy, including its size, age, the number of suns, etc. The Milky Way Galaxy is the galaxy that contains our Solar System. It's a barred spiral galaxy, one of billions in the observable universe, and has some fascinating features:And to rub salt in the wound, although that is probably the result rather than the intention of the scientists, the European Southern Observatory (ESO) has just released 200,000 images providing the most detailed map ever compiled of the Milky Way galaxy. Together the images contain 1.5 billion objects.
- Size:
- The Milky Way is about 100,000 to 120,000 light-years in diameter. Its thickness varies, but the stellar disk is approximately 1,000 light-years thick.
- The galaxy consists of a central bulge, spiral arms, and a surrounding halo. The bulge, at the center, is roughly 10,000 light-years across, while the spiral arms extend outward.
- Age:
- The Milky Way is approximately 13.6 billion years old, almost as old as the universe itself (which is about 13.8 billion years old).
- The oldest known stars in the galaxy, found in globular clusters, are about 12-13 billion years old.
- Number of Stars (Suns):
- The Milky Way is home to an estimated 100 to 400 billion stars. These stars range from small red dwarfs to massive, hot stars like our Sun. The exact number is hard to pinpoint due to the galaxy's vastness and complexity.
- Structure:
- The galaxy has a bar-shaped core of stars at its center, surrounded by four prominent spiral arms: the Perseus Arm, Scutum-Centaurus Arm, Sagittarius Arm, and Norma Arm.
- Our Solar System is located in a minor arm called the Orion-Cygnus Arm, roughly 27,000 light-years from the Galactic Center.
- Mass:
- The total mass of the Milky Way is estimated to be between **800 billion to 1.5 trillion times the mass of the Sun**. This includes stars, interstellar gas, dust, and dark matter (which makes up most of the galaxy's mass).
- Black Hole:
- At the center of the Milky Way lies a supermassive black hole called Sagittarius A* (Sgr A*), with a mass around 4 million times that of the Sun.
- Rotation:
- The Milky Way is rotating, with stars near the center orbiting the Galactic Center faster than those in the outer regions. Our Solar System takes roughly 230 million years to complete one orbit around the Galactic Center, a period called a Galactic Year.
- Dark Matter:
- Much of the mass in the Milky Way is in the form of dark matter, an invisible substance that interacts gravitationally but does not emit or absorb light. It's responsible for the galaxy's outer regions rotating faster than expected based on visible matter alone.
- Galactic Neighborhood:
- The Milky Way is part of the Local Group, a cluster of more than 50 galaxies. Its largest companion is the Andromeda Galaxy, which is on a collision course with the Milky Way and is expected to merge with it in about 4.5 billion years.
The Milky Way is just one of the many galaxies in the universe, but it is home to our planet, making it particularly significant to us!
In the name 'Sagittarius A*' what does the '*' signify?
In the name Sagittarius A* (pronounced "Sagittarius A-star"), the asterisk (*) is used to denote the specific radio source located at the center of the Milky Way, which is associated with the supermassive black hole there. The asterisk helps distinguish this particular radio source from other objects or radio emissions in the Sagittarius A region of the sky.
The asterisk doesn't have any mathematical meaning in this context; it's more of a notation to highlight that this is a unique and important source within the broader region of Sagittarius A. This designation was originally made by astronomer Robert L. Brown in 1982 to emphasize the strong radio signal observed from that precise location.
ESO telescope captures the most detailed infrared map ever of our Milky Way
Astronomers have published a gigantic infrared map of the Milky Way containing more than 1.5 billion objects ― the most detailed one ever made. Using the European Southern Observatory's VISTA telescope, the team monitored the central regions of our Galaxy for more than 13 years. At 500 terabytes of data, this is the largest observational project ever carried out with an ESO telescope.
This record-breaking map comprises 200,000 images taken by ESO's VISTA ― the Visible and Infrared Survey Telescope for Astronomy. Located at ESO's Paranal Observatory in Chile, the telescope's main purpose is to map large areas of the sky. The team used VISTA's infrared camera VIRCAM, which can peer through the dust and gas that permeates our galaxy. It is therefore able to see the radiation from the Milky Way's most hidden places, opening a unique window onto our galactic surroundings.We made so many discoveries, we have changed the view of our Galaxy forever.
Dante Minniti, project leader
Universidad Andrés Bello
Chile.
This gigantic dataset [1.1] covers an area of the sky equivalent to 8600 full moons, and contains about 10 times more objects than a previous map released by the same team back in 2012. It includes newborn stars, which are often embedded in dusty cocoons , and globular clusters –– dense groups of millions of the oldest stars in the Milky Way. Observing infrared light means VISTA can also spot very cold objects, which glow at these wavelengths, like brown dwarfs ('failed' stars that do not have sustained nuclear fusion) or free-floating planets that don't orbit a star.
The observations began in 2010 and ended in the first half of 2023, spanning a total of 420 nights. By observing each patch of the sky many times, the team was able to not only determine the locations of these objects, but also track how they move and whether their brightness changes. They charted stars whose luminosity changes periodically that can be used as cosmic rulers for measuring distances [2.1] . This has given us an accurate 3D view of the inner regions of the Milky Way, which were previously hidden by dust. The researchers also tracked hypervelocity stars — fast-moving stars catapulted from the central region of the Milky Way after a close encounter with the supermassive black hole lurking there.
The new map contains data gathered as part of the VISTA Variables in the Vía Láctea ( VVV ) survey [3.1] and its companion project, the VVV eXtended (VVVX) survey.
The project was a monumental effort, made possible because we were surrounded by a great team.
Roberto Saito, lead author
Universidade Federal de Santa Catarina
Brazil.
The VVV and VVVX surveys have already led to more than 300 scientific articles. With the surveys now complete, the scientific exploration of the gathered data will continue for decades to come. Meanwhile, ESO's Paranal Observatory is being prepared for the future: VISTA will be updated with its new instrument 4MOST and ESO's Very Large Telescope ( VLT ) will receive its MOONS instrument. Together, they will provide spectra of millions of the objects surveyed here, with countless discoveries to be expected.
More information
This research was presented in a paper entitled “The VISTA Variables in the Vía Láctea eXtended (VVVX) ESO public survey: Completion of the observations and legacy” published in Astronomy & Astrophysics (https://doi.org/10.1051/0004-6361 /202450584). Data DOI: VVV, VVVX.
Abstract
Context. The ESO public survey VISTA Variables in the Vía Láctea (VVV) surveyed the inner Galactic bulge and the adjacent southern Galactic disk from 2009–2015. Upon its conclusion, the complementary VVV extended (VVVX) survey has expanded both the temporal as well as spatial coverage of the original VVV area, widening it from 562 to 1700 sq. deg., as well as providing additional epochs in JHKs filters from 2016–2023.
Aims. With the completion of VVVX observations during the first semester of 2023, we present here the observing strategy, a description of data quality and access, and the legacy of VVVX.
Methods. VVVX took ~2000 h, covering about 4% of the sky in the bulge and southern disk. VVVX covered most of the gaps left between the VVV and the VISTA Hemisphere Survey (VHS) areas and extended the VVV time baseline in the obscured regions affected by high extinction and hence hidden from optical observations.
Results. VVVX provides a deep JHKs catalogue of ≳1.5 × 109 point sources, as well as a Ks band catalogue of ~107 variable sources. Within the existing VVV area, we produced a 5D map of the surveyed region by combining positions, distances, and proper motions of well-understood distance indicators such as red clump stars, RR Lyrae, and Cepheid variables.
Conclusions. In March 2023 we successfully finished the VVVX survey observations that started in 2016, an accomplishment for ESO Paranal Observatory upon 4200 h of observations for VVV+VVVX. The VVV+VVVX catalogues complement those from the Gaia mission at low Galactic latitudes and provide spectroscopic targets for the forthcoming ESO high-multiplex spectrographs MOONS and 4MOST.
Saito, R. K.; Hempel, M.; Alonso-García, J, et al.
The VISTA Variables in the Vía Láctea extended (VVVX) ESO public survey: Completion of the observations and legacy
Astronomy & Astrophysics 689 2024; DOI: 10.1051/0004-6361/202450584
Copyright: © 2024 The authors.
Published by The European Southern Observatory (ESO). Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)
This video sequence compares infrared and visible light views of the Lobster Nebula (NGC 6357). The visible light image created from the Digitized Sky Survey 2 and, for the central part, the ESO VLT. The new infrared image was taken with the VISTA telescope at the Paranal Observatory in Chile. In the infrared, the dust that obscures many stars becomes nearly transparent, revealing a whole host of new stars that are otherwise invisible.
Credit:
ESO/VVV Survey/Digitized Sky Survey 2/D. Minniti.
Acknowledgement: Ignacio Toledo. Music: movetwo
Acknowledgement: Ignacio Toledo. Music: movetwo
As it is, the only miracle is that there are still people who believe the description in Genesis of the Universe as a small flat planet with a dome over it far surpasses for accuracy and reliability anything that modern science can produce, and as such, with the circular reasoning that passes for religious apologetics, is evidence that Genesis was written or inspired by the god who created it.
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