by Ann » Wed May 27, 2020 5:37 am
It's fascinating to see the Earth and Moon like this.
The respective color, brightness and sizes of the Earth and Moon looks just "right" to me. (Well, me the expert.
) The Earth looks basically all white, as a consequence of our planet's rather high albedo (reflectiveness). But the faint diffraction spikes centered on the Earth are slightly bluish, which is a testament of the bluish color of our planet's oceans. The Moon, by contrast, is clearly not only smaller, but its surface brightness is lower, because of its very low albedo. Its color is beige.
Earth and Moon through Saturn's Rings. Image credit: NASA, ESA, JPL-Caltech,
SSI, Cassini Imaging Team; Processing & License: Kevin M. Gill
Are the Earth and Moon resolved? That is, does the Earth look bigger than the Earth only because of its brightness, so that the larger size of the Earth is caused by "pixel bleeding", or is the Earth sufficiently resolved that the round shape of the Earth is due to the fact that at least, say, four pixels are involved in reacting to the light from the Earth?
And what about the distance between the Earth and the Moon? The average distance between the Earth and the Moon is (if I remember correctly) about 30 Earth diameters. (Or was it 60?) The distance between the Earth and the Moon in the picture at right strikes me as slightly smaller than 30 Earth diameters, let alone 60, and in the APOD the apparent distance is very small. Of course, the Earth-Moon system could be seen at an angle, which would make the distance between the two bodies look much smaller than it really is.
Note that, in the picture at right, the image of the Moon has been artificially brightened to make it look brighter. The Moon really is quite dark.
And to think that the bright white little disk in the APOD encompasses 100% of the history of humanity, with the exception of the 12 men who have walked on the Moon.
Ann
It's fascinating to see the Earth and Moon like this.
The respective color, brightness and sizes of the Earth and Moon looks just "right" to me. (Well, me the expert. :wink: ) The Earth looks basically all white, as a consequence of our planet's rather high albedo (reflectiveness). But the faint diffraction spikes centered on the Earth are slightly bluish, which is a testament of the bluish color of our planet's oceans. The Moon, by contrast, is clearly not only smaller, but its surface brightness is lower, because of its very low albedo. Its color is beige.
[float=left][attachment=0]Earth and Moon from Saturn.png[/attachment][c][size=85]Earth and Moon through Saturn's Rings. Image credit: NASA, ESA, JPL-Caltech,
SSI, Cassini Imaging Team; Processing & License: Kevin M. Gill[/size][/c][/float] [float=right][img3="'This composite image of the Earth and moon is made from data captured by OSIRIS-REx's MapCam instrument on October 2, 2017, when the spacecraft was approximately 3 million miles (5 million kilometers) from Earth, about 13 times the distance between the Earth and Moon,' NASA explained in a blog post. 'Three images (different color wavelengths) were combined and color-corrected to make the composite, and the Moon was “stretched” (brightened) to make it more easily visible.'"]https://media.mnn.com/assets/images/2018/01/earth-moon-distance.jpg[/img3][/float]
Are the Earth and Moon resolved? That is, does the Earth look bigger than the Earth only because of its brightness, so that the larger size of the Earth is caused by "pixel bleeding", or is the Earth sufficiently resolved that the round shape of the Earth is due to the fact that at least, say, four pixels are involved in reacting to the light from the Earth?
And what about the distance between the Earth and the Moon? The average distance between the Earth and the Moon is (if I remember correctly) about 30 Earth diameters. (Or was it 60?) The distance between the Earth and the Moon in the picture at right strikes me as slightly smaller than 30 Earth diameters, let alone 60, and in the APOD the apparent distance is very small. Of course, the Earth-Moon system could be seen at an angle, which would make the distance between the two bodies look much smaller than it really is.
Note that, in the picture at right, the image of the Moon has been artificially brightened to make it look brighter. The Moon really is quite dark.
[float=right][img3="Buzz Aldrin, the second man on the Moon, photographed by Neil Armstrong, the first man on the Moon. "]https://www.nasa.gov/centers/glenn/images/content/297167main_apollo_11_946-710.jpg[/img3][/float]And to think that the bright white little disk in the APOD encompasses 100% of the history of humanity, with the exception of the 12 men who have walked on the Moon.
Ann