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I wonder which of these images is the "realest". The definition of "real" that first jumps to mind is how closely the image reflects the mass of the bodies in

I wonder which of these images is the "realest". The definition of "real" that first jumps to mind is how closely the image reflects the mass of the bodies in the galaxy, but I also wonder if there are other thought-provoking definitions?

irixusr 11y ago
I'm not astrophysicist, but I would think they're all as real they just give different information about the underlying structure and events of the universe. Perhaps a the question should be, "which wavelength is more useful?"?
- metalliqaz 11y ago
  I think he actually means, "which one shows the most actual stuff." In that case, I'd say one of the infrared spectrums would be it.
mrbunnyman 11y ago
So its complicated... They are all "real" and very useful in different ways. Its important to remember that they are all maps of different thing depending on how transparent the things they are mapping are. For example the dark clouds in the optical are nearby cold / dense clouds of gas where stars are forming. They block almost all the visible light from the stars behind them. If you want to study star formation (my PhD) you can learn a lot by looking at how they absorb light, or you can look at a different wavelength and look inside / through them (microwave). You have to remember that the maps are measuring how bring sources are (at each wavelength) filtered by how absorptive the stuff along the line of sight is (at each wavelength). In the same way that images of far away galaxies are looking back in time, images at different wavelengths probe different distances and temperatures in our galaxy, but in a much messier way.
stargazer-3 11y ago
An interesting question! If it's mass you're after, you need to consider that different wavelengths trace different condensations of mass. Here are some examples that follow the mass of stars in different evolutionary stages: 1) In visible light, you can pretty easily deduce the masses of the stars if you correct for their light shifting to red as it passes through interstellar material. As the star spectra often peak in optical wavelength, the optical image is the "realest" for the star mass 2) When the stars have just been formed, they are still obscured by what we call dust - tiny micron-sized carbon-core particles that are annoyingly good at absorbing optical light. The best tracer for this mass regime would be infrared light, since the dust allows for some transmission. 3) Before the stars are formed, their mass resides in a diffuse (more so than any vacuum in our science labs) yet massive (10^3-10^7 solar masses) molecular clouds. They are typically very cold (~20 K) and their emission peaks at far-infrared light.

irixusr 11y ago

I'm not astrophysicist, but I would think they're all as real they just give different information about the underlying structure and events of the universe. Perhaps a the question should be, "which wavelength is more useful?"?

metalliqaz 11y ago
I think he actually means, "which one shows the most actual stuff." In that case, I'd say one of the infrared spectrums would be it.

mrbunnyman 11y ago

So its complicated... They are all "real" and very useful in different ways. Its important to remember that they are all maps of different thing depending on how transparent the things they are mapping are. For example the dark clouds in the optical are nearby cold / dense clouds of gas where stars are forming. They block almost all the visible light from the stars behind them. If you want to study star formation (my PhD) you can learn a lot by looking at how they absorb light, or you can look at a different wavelength and look inside / through them (microwave). You have to remember that the maps are measuring how bring sources are (at each wavelength) filtered by how absorptive the stuff along the line of sight is (at each wavelength). In the same way that images of far away galaxies are looking back in time, images at different wavelengths probe different distances and temperatures in our galaxy, but in a much messier way.

stargazer-3 11y ago

An interesting question! If it's mass you're after, you need to consider that different wavelengths trace different condensations of mass. Here are some examples that follow the mass of stars in different evolutionary stages: 1) In visible light, you can pretty easily deduce the masses of the stars if you correct for their light shifting to red as it passes through interstellar material. As the star spectra often peak in optical wavelength, the optical image is the "realest" for the star mass 2) When the stars have just been formed, they are still obscured by what we call dust - tiny micron-sized carbon-core particles that are annoyingly good at absorbing optical light. The best tracer for this mass regime would be infrared light, since the dust allows for some transmission. 3) Before the stars are formed, their mass resides in a diffuse (more so than any vacuum in our science labs) yet massive (10^3-10^7 solar masses) molecular clouds. They are typically very cold (~20 K) and their emission peaks at far-infrared light.