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Physics Photo of the Week

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Physics Photo of the Week December 20, 2024  Galaxy M33 - Color photo by Donald Collins, College View Observatory Several weeks ago I published a monochrome image of the Galaxy M33 . The gray scale of astronomical photos are rather dull compared to the photos printed in color.  The color in astro photos also reveal much more about the physics of the astronomical objects - especially galaxies.  In this deep sky image of the galaxy that is several million light years distant from our planet Earth, all the discrete stars that we see in the image are foreground stars that exist rather close to us within our own Milky Way galaxy.  The billions of stars in the distant galaxy are so far away and so numerous that they blend together to resemble clouds.  Notice that the clouds of stars in the outer spiral arms of Galaxy M33 appear bluish, while the star clouds near the core of the galaxy are more reddish.  These colors mainly refer to the average temperatures of th...
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Physcis Photo of the Week

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Physics Photo of the Week December 6, 2024 Wake in clouds from mountain peak - satellite photos composed by D. Collins   The satellite image above shows the northeastern US in mid-winter (February 2024).  The left half of the image shows the many snow-covered lakes in the Adirondacks of northern New York.  The middle section shows snow-covered mountain ridges of Vermont that run north and south.  The mid right-center section shows a interesting piece of New Hampshire and a small gap in the clouds running southeast of a special white spot.  The white spot is the snow-capped summit of Mt. Washington breaking through the clouds and illuminated by the rising Sun. The zoomed-in image at right shows the effect.  Mt. Washington's summit, at 6288 ft. above sea level, is the highest mountain point in the northeastern US*.  The summit has p enetrated the cloud layer that was blowing towards the southeast.  The downstream part of the clouds show a wake in...
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Physics Photo of the Week

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Physics Photo of the Week November 22, 2024 Galaxy M33 - The Triangulum Galaxy The Triangulum Galaxy (M 33) is located in the Triangulum constellation fairly close to the more famous Andromeda Galaxy in the sky, and is about the same distance from the Earth (between 2 million and 3 million light years).  The Triangulum Galaxy,  is smaller (less massive) and fainter than the Andromeda Galaxy, but it appears more delicate and seems to show more discete clouds of stars and a number of large clusters in its spiral arms.   At right is a photo of the Andromeda Galaxy, but taken with a smaller focal length telescope.  The Andromeda galaxy covers a much larger proportion of the sky (about 3 degrees across) compared with the angular size of the Triangulum galaxy (about 1/3 degree across).  Short focal length telescopes show a larger field of view than long focal length telescopes, hence the Andromeda appears smaller than the Triangulum in these telephotos.  The...
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Physics Photo of the Week - November 8, 2024

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Physics Photo of the Week - November 8, 2024 Aurora from Swannanoa On May 10, 2024, much of North America experienced a "solar storm" that produced aurora as far south of the Carolinas.  Aurora (northern lights) are usually confined to the Earth's polar regions (northern Canada, Alaska, Norway, Sweeden, Russia, ...).  The aurora are produced by charged particles (electrons and protons) that are emitted by the Sun ( solar wind ) which are guided by magnetic fields in the solar system.  The Sun had emitted a massive amount of high energy electrons and protons a couple of days earlier - called a " Coronal mass ejection ".  When these particles reach the Earth, t hey strike the atoms and molecules in the Earth's upper atmosphere and cause the atmosphere to glow.  This is analogous to the glow on an old-fashioned TV picture tube when electrons strike the coating on the inside of the tube.   With a coronal mass ejection, the number of charged particles ejecte...
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Physics Photo of the Week - Sept. 27, 2024

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  Physics of a splash of water This week's photo shows details of the splash observed when a tennis ball was thrown into a body of water.  The ball was thrown from someone on shore when a slo-mo video was recorded on a smart phone.  This is the first video frame immediately after the ball landed in the water.  The immediate reaction from the water is the ejection of a crown-shaped splash that we see in the photo.     A few frames later we can see the rebound effect sending a long column of water shooting up from the splash area as a rebound effect of the water - seen in the photo at right. Click on either of the images to view a slo-mo video of the ball approaching the water, the immediate crown effect, then the spout of water as a result of the rebound of the water as the water rushed back into the sizable cavity made by the ball when it hit the water from a height of a few meters. Examining the slo-mo video frame-by-frame we can see that the kinetic ener...
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Video clip

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  Video made with the slo-mo application of my smart phone, and played back at 2 frames per second.
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Physics Photo of the Week Reflections and Mirages

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Physics Photo of the Week  September 13, 2024 Reflections and Mirages Lakes are always very photogenic when the mountains and other objects are reflected in the water.  However, there are two kinds of reflections in this week's photo, although only one kind of reflection (the direct simple reflection) is seen.  We first notice the reflection of the diving platform close by and the prominent reflection of the background mountain, Mt. Hor, that overlooks Willoughby Lake in Vermont.   The images below show a close-up of the raft and a close-up of the more distant shore of the lake from the left center part of the photo:   The reflections from the close-up of the raft are clear, however the raft's reflections are distorted by the small ripples of the water surface.  The reflections of the background trees, especially the tree-tops are also distorted by the water ripples.  Somewhat like fun-house mirrors that have curved surfaces. The close-up of the dista...
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