APOD: Gaia: Here Comes the Sun (2024 Aug 04)

[APOD Robot]

Gaia: Here Comes the Sun

Explanation: What would it look like to return home from outside our galaxy? Although designed to answer greater questions, data from ESA's robotic Gaia mission is helping to provide a uniquely modern perspective on humanity's place in the universe. Gaia orbits the Sun near the Earth and resolves stars' positions so precisely that it can determine a slight shift from its changing vantage point over the course of a year, a shift that is proportionately smaller for more distant stars -- and so determines distance. In the first sequence of the video, an illustration of the Milky Way is shown that soon resolves into a three-dimensional visualization of Gaia star data. A few notable stars are labelled with their common names, while others stars are labelled with numbers from a Gaia catalog. Eventually, the viewer arrives in our stellar neighborhood where many stars were tracked by Gaia, and soon at our home star Sol, the Sun. At the video's end, the reflective glow of Sol's third planet becomes visible: Earth.

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[Roy]

Interesting - perspective - runs both ways. Just need to find other water worlds.

[wilddouglascounty]

Does anyone know of anyone who has made a volumetric depiction of the visible night sky? I have looked for years for such a depiction, but in vain. There are many, many depictions of our stellar neighborhood from an external, 3D position, zooming in like an interstellar ship from a distance away the sun but never from the perspective of someone on the ground looking up at the sky.

Such a volumetric depiction of the sky we look up at with our naked eye would require a gigantic exaggeration of parallax so that nearby stars would move more than the stars further away when you moved your head from side to side, but I think such a depiction of the sky would be fascinating and allow us to appreciate the night sky in a whole new way. If, instead of the all of the stars being fixed on the same celestial dome, our visible night sky could have that dome expanded out to the band of stars of the Milky Way, then all the stars closer than that could be seen in a perceivable 3D volumetric space, so you could explore the constellations in a whole new way. You could not only see that Rigel is further away than Betelgeuse by wiggling Orion, you could explore the which parts of the sky seem empty compared to other areas, giving you a real sense of the 3D volume of space we are surrounded by.

Of course I'm talking about visible stars only, just to give an appreciation for the volumes of space that you see when you walk outside and look up. It would be great to have the option of including the many, many red dwarfs and other fainter stellar objects that share our neighborhood as well if you wanted to "see" how they fit in, too. Anyone know of such a resource? And if not, anyone want to do that for us?

[Ann]

I really, really recommend this video by Anton Petrov, where he discusses a map of the nearest 10 parsecs around the Sun, based on Gaia's measurements:

Click to play embedded YouTube video.

An older map, based on Hipparcos less accurate measurements, looks like this (and don't ask me why Sirius appears to be so extremely close to the Sun). However, the Hipparcos map appears to be mostly about measuring the diameters of the stars.

tellar diameters can be measured for some nearby giant and supergiant stars by using a technique called stellar interferometry. The Navy Prototype Optical Interferometer has been operating for over a decade at Mount Wilson Observatory, and routinely measures the angular diameters of bright stars to fractions of a milli arcsecond (0.001 arcseconds) accuracy. The table below shows only a few stars that have had their diameters measured. Once their distances are accurately known...from the Hipparcos Survey...their linear diameters in millions of kilometers can easily be found.

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Ann

[wilddouglascounty]

Thank you, Ann for a very good presentation and an interesting website. However it, like all other depiction of the local region of our galaxy, does not translate the information into a depiction of the sky as you see it when you walk outside on a dark moonless night. Translating those 3-4000 visible stars into a volumetric space just hasn't been done, in my estimation.

[VictorBorun]

Thank you, Ann for a very good presentation and an interesting website. However it, like all other depiction of the local region of our galaxy, does not translate the information into a depiction of the sky as you see it when you walk outside on a dark moonless night. Translating those 3-4000 visible stars into a volumetric space just hasn't been done, in my estimation.

adding my own grievance: a star map tends to show me more faint stars than I like. I have hard time making out the constellations which used to jump at me from the real-life night sky

the gears at work here IMHO are the infographist's poor self-control of the urge to feed you all they know as soon as they think of it

[Chris Peterson]

Thank you, Ann for a very good presentation and an interesting website. However it, like all other depiction of the local region of our galaxy, does not translate the information into a depiction of the sky as you see it when you walk outside on a dark moonless night. Translating those 3-4000 visible stars into a volumetric space just hasn't been done, in my estimation.

adding my own grievance: a star map tends to show me more faint stars than I like. I have hard time making out the constellations which used to jump at me from the real-life night sky

the gears at work here IMHO are the infographist's poor self-control of the urge to feed you all they know as soon as they think of it

When I lived in California the constellations were easy. But most are a challenge here in Colorado, where all 3000+ visible stars actually are visible, and it's difficult to pick out all but the most prominent constellations.