APOD: Journey into the Cosmic Reef (2020 May 18)

[APOD Robot]

Journey into the Cosmic Reef

Explanation: What would you see if you could fly into the Cosmic Reef? The nebular cloud NGC 2014 appear to some like an ocean reef that resides in the sky, specifically in the LMC, the largest satellite galaxy of our Milky Way Galaxy. A detailed image of this distant nebula was taken by the Hubble Space Telescope to help commemorate 30 years of investigating the cosmos. Data and images of this cosmic reef have been combined into the three-dimensional model flown through in the featured video. The computer animated sequence first takes you past a star cluster highlighted by bright blue stars, below pillars of gas and dust slowly being destroyed by the energetic light and winds emitted by these massive stars. Filaments of gas and dust are everywhere, glowing in the red light of hydrogen and nitrogen. The animation next takes you to the blue-colored nebula NGC 2020, glowing in light emitted by oxygen and surrounding a Wolf-Rayet star about 200,000 times brighter than our Sun -- a nebula thought to be the ejected outer atmosphere of this stellar monster. As the animation concludes, the virtual camera pivots to show that NGC 2020 has a familiar hourglass shape when viewed from the side.

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[bystander]

viewtopic.php?t=40502

[AVAO]

From where does the assumption come that, viewed from the side, it is an hourglass shape? This is typical for planetary nebulae, but not espacially for Wolf-Rayet stars?

[BeeWry]

I often wonder when viewing simulations like this - just how fast is the viewer apparently moving? I have to guess it would be many times the speed of light.

[orin stepanek]

Awesome! I enjoyed the video very much!

[Devil Particle]

The amount of energy needed to achieve the changing camera perspectives!

[RJN]

Due to an email from a member of the video-creation team, the credit has now been changed on the main NASA APOD.

[Engage]

I often wonder when viewing simulations like this - just how fast is the viewer apparently moving? I have to guess it would be many times the speed of light.

Yes, warp 7, in fact.

[neufer]

I often wonder when viewing simulations like this - just how fast is the viewer apparently moving? I have to guess it would be many times the speed of light.

Yes, warp 7, in fact.

So we only travel 7³= 343 light minutes over the minute of video

[johnnydeep]

I often wonder when viewing simulations like this - just how fast is the viewer apparently moving? I have to guess it would be many times the speed of light.

Yes, warp 7, in fact.

So we only travel 7³= 343 light minutes over the minute of video

Clearly, it's much faster than that. Assuming we are travelling at least 300 light years in 1 minute, that would end up being 60 * 24 * 365 * 300 = 157,680,000 c. Not too shabby!

[Cousin Ricky]

I assume that we do not yet have the technology to measure stellar distances in the LMC at the resolution required by this visualization. So how did they determine which stars are closer to us and which stars are farther away?

[majoroz]

[ Gushing reaction ] :

Kudos to the animation team. Great stuff.

.....to go where no man has gone before.....

[Sa Ji Tario]

Why worry about those detealles ?, Let's enjoy the elaboration of the images that are the most exact approximation

[The naked eye]

Unfortunately almost evrything shown in the vídeo wouldn't be visible for the naked eye travelling around there. Just something as marvelous as the pale grey milky way we are able to see in the sky.

[neufer]

I often wonder when viewing simulations like this - just how fast is the viewer apparently moving?
I have to guess it would be many times the speed of light.

Assuming we are travelling at least 300 light years in 1 minute,
that would end up being 60 * 24 * 365 * 300 = 157,680,000 c. Not too shabby!

Optimal space travel for humans involves constant 1-Gee acceleration:
http://asterisk.apod.com/viewtopic.php? ... 83#p301783

Taking into account time dilation (or Fitzgerald contraction)
the effective 1-Gee space ship velocity past the LMC is ~163,000 c
(so it still has to be speed-ed up by a factor of ~1,000).

Effective 1-Gee space ship velocity ~ c x sqrt[(1 + D)²-1] ... or ~ c x D

• (where D = the object's distance from Earth in light years).

Note that ~2.3 eV photons are Doppler shifted into ~750 keV hard X-Rays/gamma rays
and will require a hires forward looking telescope to observe this experience.

[The naked eye]

Unfortunately almost evrything shown in the vídeo wouldn't be visible for the naked eye travelling around there. Just something as marvelous as the pale grey milky way we are able to see in the sky.

...the pale grey Milky Way and bright stars...

[geckzilla]

Unfortunately almost evrything shown in the vídeo wouldn't be visible for the naked eye travelling around there. Just something as marvelous as the pale grey milky way we are able to see in the sky.

oh darn! I was looking forward to flying around faster than light so photons can't even get to my eyes. You're telling me that the light that won't make it to me won't even look like the video? Way to kill my dreams

[BeeWry]

Yes, warp 7, in fact.

So we only travel 7³= 343 light minutes over the minute of video

Clearly, it's much faster than that. Assuming we are travelling at least 300 light years in 1 minute, that would end up being 60 * 24 * 365 * 300 = 157,680,000 c. Not too shabby!

That's in the neighbourhood of what I imagined it to be! Thanks for the calculation.

[The naked eye]

Unfortunately almost evrything shown in the vídeo wouldn't be visible for the naked eye travelling around there. Just something as marvelous as the pale grey milky way we are able to see in the sky.

oh darn! I was looking forward to flying around faster than light so photons can't even get to my eyes. You're telling me that the light that won't make it to me won't even look like the video? Way to kill my dreams

Very interesting point. I didn't consider It! My point is that even being steady there without a light enhancement device the naked eye will only see something similar to a starry night here. In some way I consider colourfull amazing deep space images as misleading. Even a black shoe whith enough light enhancement will appear bright colorfull.

[Chris Peterson]

Unfortunately almost evrything shown in the vídeo wouldn't be visible for the naked eye travelling around there. Just something as marvelous as the pale grey milky way we are able to see in the sky.

oh darn! I was looking forward to flying around faster than light so photons can't even get to my eyes. You're telling me that the light that won't make it to me won't even look like the video? Way to kill my dreams

Very interesting point. I didn't consider It! My point is that even being steady there without a light enhancement device the naked eye will only see something similar to a starry night here. In some way I consider colourfull amazing deep space images as misleading. Even a black shoe whith enough light enhancement will appear bright colorfull.

If simply enhancing the colors of an apparently black shoe reveals things our eyes can't see, it is our eyes that are misleading, not the imaging technique.

[Cousin Ricky]

Very interesting point. I didn't consider It! My point is that even being steady there without a light enhancement device the naked eye will only see something similar to a starry night here. In some way I consider colourfull amazing deep space images as misleading. Even a black shoe whith enough light enhancement will appear bright colorfull.

If simply enhancing the colors of an apparently black shoe reveals things our eyes can't see, it is our eyes that are misleading, not the imaging technique.

Exactly! And that is astrophotography color enhancement and wavelength assignment in a nutshell.

[geckzilla]

The only thing I find even remotely misleading about space images is that nebulas are probably a lot greener than we let it be. The blue just looks so much more appealing that [O III] emission is nearly always assigned a blue hue. Note, however, there aren't any green stars. Green stars? weird. Green nebulas? probably all over the place.

[neufer]

False color green Voorwerpjes represent oxygen emission lines.

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The only thing I find even remotely misleading about space images is that nebulas are probably a lot greener than we let it be... Note, however, there aren't any green stars. Green stars? weird. Green nebulas? probably all over the place.

Thermal black-body radiation drops off exponentially at short wavelengths such that one can discern both red & orange stars. However, once the peak gets to yellow/green near the center of our vision it fires up all our vision cones and appears white (by definition?).

Blue stars peak in the UV.

[geckzilla]

---

The only thing I find even remotely misleading about space images is that nebulas are probably a lot greener than we let it be... Note, however, there aren't any green stars. Green stars? weird. Green nebulas? probably all over the place.

Thermal black-body radiation drops off exponentially at short wavelengths so we can discern both red & orange stars. However, once the peak gets to yellow/green near the center of our vision it fires up all our vision cones and appears white (by definition?).

I can't even get them out of data, though. Like you'd have to either be using a specific set of filters to make them look green. Don't think you'd get green stars as long as you're using wideband visible filters.

[neufer]

I can't even get them out of data, though. Like you'd have to either be using a specific set of filters to make them look green. Don't think you'd get green stars as long as you're using wideband visible filters.

• No. We evolved to make yellow/green sunlight appear white.

<<In the first [Oz] book, The Wonderful Wizard of Oz (1900), the walls are green, but the city itself is not. However, when they enter, everyone in the Emerald City is made to wear green-tinted spectacles. This is explained as an effort to protect their eyes from the "brightness and glory" of the city, but in effect makes everything appear green when it is, in fact, "no more green than any other city". This is yet another "humbug" created by the Wizard.

One scene of the Emerald City is of particular note in the development of Oz: Dorothy sees rows of shops, selling green articles of every variety, and a vendor who sells green lemonade from whom children bought it with green pennies. This contrasts with the later description of Oz, in which money does not feature. Interpreters have argued that the Wizard may have introduced money into the city.

In this book, the Wizard also describes the city as having been built for the Wizard within a few years after he arrived. It was he who decreed that everyone in the Emerald City must wear green eyeglasses, since the first thing he noticed about Oz after he landed in his hot air balloon was how green and pleasant the land was.>>