Oh good, there isn't a hidden civilization there. Whew.
From a million miles away, NASA camera shows moon crossing face of Earth
141–150 of 159 posts
Re: From a million miles away, NASA camera shows moon crossing face of Earth
#142[deleted]
Re: From a million miles away, NASA camera shows moon crossing face of Earth
#143Is this the real reflectance of the moon? Seems so dark. Usually we see the moon at night surrounded by night sky, which probably skews our perception of the real color of the surface material.
Yes. I remember reading somewhere (Wikipedia probably) the moon is only about as reflective as asphalt, believe it or not. Imagine how much brighter moonlight would be if it were painted brilliant white (e.g. titanium dioxide pigment). I'd love to see a simulation. Would it be bright enough so we could see enough scattering that the sky would appear blue, I wonder.
Re: From a million miles away, NASA camera shows moon crossing face of Earth
#144Earlier quoted context omitted.
I don't find these kind of replies disheartening. I think scepticism of NASA is a good thing. Because some of that scepticism might translate into new research, new developments, new experiments, and maybe even new entrepreneurial efforts in space.
Tobold is not describing rational skepticism of NASA's ability to fulfill its mission. Tobold is describing conspiracy theories and people who have fundamental misunderstandings of science.
Maybe if we discredit the last thousand-odd of years of scientific progress and history and start over from scratch, someone will discover magic and we can all fly to the moon on the back of aether turtles.
Re: From a million miles away, NASA camera shows moon crossing face of Earth
#145Honest question: Why don't the clouds seen on Earth show any activity or movement over the course of this time lapse?
There definitely is some movement: Look at the fine features of the northern arm of the vortex in the South, they change quite a bit. Also, there are some clouds growing just east of the Gulf of California. [EDIT] As it's arguably hard to spot with the low frame rate and movement I uploaded a stabilized and sped up version. It's centered on a cloud patch in the Pacific. You can now clearly see a cloud west of it disa…
Wow that looks much better than the original.
Re: From a million miles away, NASA camera shows moon crossing face of Earth
#146This is exactly the shot I've been hoping for since we got that first image of the Earth from DSCOVR. I tried to make an educated guess of how large the moon would appear from a million miles away, and I have to admit I far underestimated how large it would appear.
Re: From a million miles away, NASA camera shows moon crossing face of Earth
#147Earlier quoted context omitted.
Dang.. it never occurred to me how big the moon is. Looking at this picture, it's hard for me to comprehend why the moon would orbit the earth and not fall into the sun.
The gravitational influence of the Sun on the Moon is greater than the gravitational influence of the Earth. In a very real way, the moon is orbiting the Sun. However, the orbit it flies around the Earth only very slightly modifies it's orbit around the Sun. The lunar orbital speed around the earth is ~1km/s, while the orbital speed around the sun is ~30km/s. That is, it never loops backwards on it's path around the…
Is this also true of Jupiter's moons?
Re: From a million miles away, NASA camera shows moon crossing face of Earth
#148Earlier quoted context omitted.
"EPIC’s “natural color” images of Earth are generated by combining three separate monochrome exposures taken by the camera in quick succession. EPIC takes a series of 10 images using different narrowband spectral filters -- from ultraviolet to near infrared -- to produce a variety of science products. The red, green and blue channel images are used in these color images. Combining three images taken about 30 seconds…
You'd think they could be smarter about combining the R,G,B images. E.g., allow for the thing under each pixel to have moved a little from one image to the next, look at all their narrowband images (which will typically be strongly correlated, especially for nearby wavelengths) to estimate how fast each part of the image is moving, and then to get a pixel in the final image combine its G with slightly offset (maybe i…
It seems like you have re-discovered why segmenting the lunar image and shifting it backwards in time, to align the three color planes, was not done. They don't have the information to fill in the resulting gap, because it was occluded. In a very real sense, they have nothing to put in those pixels.
If they had wanted to do it, they could have. The ephemeris (i.e., basic imaging geometry relating to the location of Earth, Moon, and camera) will be very well-known. That bread-and-butter image processing is no problem.
The historical context here is that NASA centers, prominently JPL, were among the inventors of what became digital image processing (https://en.wikipedia.org/wiki/Digital_image_processing#Histo...).
Re: From a million miles away, NASA camera shows moon crossing face of Earth
#149It is really cool how the NASA gives us a better understanding of the universe and our place in it by publishing all these nice pictures. However, I would like to have one easy accessible source for all the nice pictures that is daily updated and could be synchronized to a local school server e.g. with rsync. Is there one "ḧere-are-all-the-pics"-ftp server anywhere? It is quite time consuming to browse the hundreds o…
What would be really cool too, is something like http://himawari8.nict.go.jp/ with the (more-or-less) real-time pictures from DSCOVR.
Re: From a million miles away, NASA camera shows moon crossing face of Earth
#150Earlier quoted context omitted.
When the moon casts a shadow on the earth we (on the surface) experience it as a solar eclipse. For these images, the moon is not directly between the sun and the earth, so it cannot block sunlight from hitting the earth. So, no shadow.
But the satellite is at the L1 Lagrange point which is between the earth and the sun. So if you see the moon pass in front of the earth from L1 shouldn't the moon then also be directly between the earth and the sun? And as someone in another post noted: you can see the suns reflection in the ocean. And the moon passes directly over this spot.
All you can take away from the moon passing over the sun's reflection is this. The moon crossed over the sunlight reflected from the earth. To create a shadow, the moon must cross through the light emitted from the sun.
This image might better help explain. Since the earth's orbital plane is in a different xy plane than the moon's, the moon crossing over the reflection guarantees nothing about whether it crossed the sun's emitted light.
http://www.cnyo.org/wp-content/uploads/2014/04/2014april10_e...
