Starship Asterisk*

Wow, so it is now officially over 50 years since any human was on the Moon. A brief period, from July 20, 1969 to December 14, 1972, in which period 12 people walked on the Moon. All of them were Americans, and no other nation or group has, to date, done the same. It makes me wonder, in a strange le...

The Turkey Drumstick Nebula©️ Ha ha. Yes, nice. And that reminds me -- I'm thankful today for APOD. For the faithful work that has curated this unique collection and gives us daily joy, looking at so many mind-expanding views of the universe, with explanations of some of their interesting and often...

. . . So, Mark, why does Uranus look so green in today's APOD? Well, duh. People process their images differently. And Uranus certainly is sort of green- ish - just not as green as it is made to look in today's APOD, if you ask me. Ann ========== I believe the green color is also caused by photo pr...

So an observer at Uranus would have seen a transit of the Earth. Pretty cool. Without thinking too hard about the effects of astronomical aberration (the error in apparent position due to the finite speed of light), it would actually be a double transit. The Moon would transit the Earth while the E...

Capturing Uranus at the limb of the eclipsed Moon is a very fine achievement! Congratulations! But of course... I am not the Color Commentator for nothing. So what about the color of Uranus? This is what it looks like in the APOD: APOD 11 November 2022 detail.png What does Uranus look like in other...

heehaw wrote: ↑Mon Oct 31, 2022 10:45 pm

Iksarfighter wrote: ↑Mon Oct 31, 2022 12:07 pm It is a Fake p)

Oh no...don't tell me they got me AGAIN! Halloween! Touché!

??? Why do you say this is fake?

Interesting assortment of moon reflections. Most are highly elongated and spread out lineally along the line of sight. Can a point source star also look like that? At first I thought that it's because the moon isn't a point source, but here's a nice clear reflection of the moon in water that is not...

In motion how? Ripples up and down? Why would the stars all appear spread out in parallel straight line segments like that? There also seem to be too many very bright stars and not enough other ones compared to the sky above. Does light vibrate atoms or do atoms vibrate light or both ? :? Or neithe...

johnnydeep wrote: ↑Fri Oct 21, 2022 9:31 pm Are the short line segments reflected in the water stars or something else? But if stars, I would have expected them to look like points not lines, like in this old APOD - https://apod.nasa.gov/apod/ap140916.html

The water surface must have been a little bit in motion relative to the camera.

There was some interesting further discussion of the DART findings on a YouTube comments section. It seems that the initial finding is that Dimorphos slowed down a lot more than would have been predicted by calculating the inertia of the DART spacecraft. I and others were wondering what effects migh...

Still doesn't make sense to me. I see "objects" that are way bigger than single pixels in the short video. And I'm still not sure why the multi-pixel blob starts out as a small sphere, then expands to a larger sphere before having a large part of it blown off (presumably by the DART impac...

So, " the initial dot is primarily Dimorphos's larger companion: asteroid Didymos. " means that the central sphere we see at first is really the combined images of Dimorphos and Didymos, possibly with Dimorphos partially or fully overlapping Didymos? I think the resolution is such that th...

FLPhotoCatcher wrote: ↑Fri Oct 14, 2022 6:19 am About two days ago, I actually watched a video that featured this photo.

Here it is.
https://www.youtube.com/watch?v=BdCizNwLaHA

Thanks! I love Scott Manley . . . there was a lot in his video.
This APOD reminded me of one from last May:
https://apod.nasa.gov/apod/ap220531.html

Just an odd set of thoughts here. If Europa has enough energy being imparted to it, then the subsurface water could indeed be liquid. I don't know if it's proper to call that an ocean, but for want of a better term, then, yes, an "encased ocean". Does this make life likely? Since we don't ...

An example of why we often use pseudocolor palettes when trying to get more out of an image. I've converted the original to grayscale and then applied a common pseudocolor mapping used for astronomical images. It results in an image that lets our eyes see more detail than would otherwise be apparen...

LOL. I put "DART NASA mission" into Google on a Chromium browser and got a rather unusual, animated result.

... I wonder why the flight of the thrown materials sometimes shows large wavy lines? https://live.staticflickr.com/65535/52392194248_b70572f9cf_c.jpg Original Image Credit: ASI/NASA Actually, I would refer you to the Scott Manley YouTube video linked just above by FLPhotoCatcher: https://www.youtu...

Something puzzles me about time-lapse videos. I used to think that time speeds up in time-lapse. Say a year passes by in a couple of minutes in the video. But here in NASA's page under Dimorphos they state that Dart impacted the satellite at a speed of 6.6 kilometers a second. Then they state that ...

This beautiful graphic really surprises most people the first time they see it. My reaction was: "Really, that's all? It seems an awfully small amount." For Mars or the Moon, of course, there is water on both, but I don't know if you could even see the liquid drop on an analogous graphic f...

Good points, johnnydeep and Chris. Just to clarify what I was talking about in my point 3, --- 3 --- What about red shifts or average brightness of the stellar populations? Are any differences measurable for the nearest versus the farthest arms? I have no idea. I wonder if effects from the dust in a...

It struck me as odd that anyone on Italy's Mediterranean coast could see a sunrise like this, as it faces west. Sure enough, the picture was taken on Italy's Adriatic coast, which does face east. Hmmm. Interesting. Yes, this was on the eastern coast of Italy, capturing a sunrise over the Adriatic. ...

Thanks for the encouragement Ann !
I certainly appreciate your postings, too, they add a lot of value to APOD.

One thing I've often wondered about these pictures of distant galaxies, especially ones that are from an angle like this one. These galaxies are tens of thousands of light years across, often more than a hundred thousand light years across. This means that our view of the far side of the galaxy is ...

When did Hubble start operating in the infrared ? Near-IR extends out to around 2 micrometers, where we're still seeing what we might think of as ordinary light. Uncooled silicon sensors such as those on the HST can be used to that wavelength (and the HST has filters out that far). Longer than that...

I think because the mountain range is really far from the city, it doesn't cover that much of the sky. So it it should cover just around 5 o high. If you look at the star trails, if it was any higher than 15 o their trail's curve would have been greater, at least that is what I think. I apologize f...