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----------------------- # 1600 - Comet ISON coming towards us.
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-Comet ISON is on its way here! Well, not here, here, but, near hear. On November 8 it will only miss us by 40,000,000 miles. It just missed the planet Mars on October 13 by only 10,000,000 miles. On November 18 the comet will miss Mercury by 22,000,000 miles. It will loop around the Sun on November 28 passing within 683,500 miles of the surface. (The Moon is 235,000 from Earth’s surface.) Hopefully on December 8, 2013 we will see ISON after it looped around the Sun and started traveling back out into space, if it can survive the loop.
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- The comet started as a chunk of ice, dust, and frozen gases at the outer edges of the Solar System. Part of the Oort Cloud, a cloud of a trillion small icy bodies orbiting the Sun nearly a lightyear away. This is 1,000 times more distant than the dwarf planet Pluto.
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- Somehow this comet got nudged out of its peaceful stable orbit. It is now speeding towards the Sun at 46,800 miles per hour. Its closest approach to the Sun occurs at 10:41 AM on November 28. The close encounter will raise the surface temperature to 2,000 C. It is frozen ice but its outer layers will boil off the frozen surface. It may not totally melt. Like a baked Alaska the frozen ice cream center may survive. Astronomers are anxious to learn if the nucleus does survive, regardless, the tail of debris will still be returning.
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- As the sunlight warms the comet, a dirty snowball, the ultraviolet radiation ionizes molecules on its surface. The magnetic field of the Solar Wind drags these charged particles away from the Sun to create a streamer tail on the comet.
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- Nothing in the Universe disappears. It may change form. It may disintegrate. Going from a dusty snowball to a trail of particles the size of wood smoke. The Earth will pass through this tail of gas and dust on January 12, 2014
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- The comet ISON was first discovered on September 21, 2012 as part of a routine sky survey designed to track space debris. It was first discovered by amateur astronomers, members of the International Scientific Optical Network, ISON. The comet blew off frozen carbon dioxide when it was 460,000,000 miles from the Sun. As the comet approaches the Sun the ice and dust boil off to form a coma ( head ) and a tail that has the potential to be as bright as the full moon. However, there is much speculation as to how bright it may get and if it will even be visible to the naked eye.
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- This does not bother astronomers. There will be 16 NASA spacecraft as well as the International Space Station instruments focusing on this comet. It appears that this is the first visit of this comet to the inner Solar System. It was formed 4,560,000,000 years ago. Spectrograph images of the light radiation will tell astronomers what elements the comet is made of. In what proportions. Analyzing these elements will tell the story about the comet’s formation and the composition of the early Solar System. Each piece of the comet represents solar nebula composition formed by temperatures and distances from the Sun. The formation of the early Solar System can be recreated with this data.
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- Already the Hubble Space Telescope has captured an image of a 2,500 mile high geyser shooting out from the comet’s surface. Analyzing the images astronomers estimate the comet nucleus to be 2.5 miles diameter. If we assume the comet is a perfect sphere with a diameter of 6 kilometers, with an average density of water, 1 gram / cm^3, or, 1,000 kilograms / meter ^3, then the mass of the comet would be 11,000,000,000,000,000 kilograms. (1.1 * 10^16 kg).
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- A fully loaded oil tanker weighs 10^8 kilograms ( 20,000 tons ). So this comet has the weight of 100,000,000 oil tankers. I am so happy it is not going to hit us.
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------------------- Volume of Sphere = 4/3 * pi * r^3
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------------------ Volume = 4.19 * (3000 m)^3
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------------------- Volume = 1.1 * 10^11 meters^3
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-------------------- Mass = density * volume
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-------------------- Mass = 1,000 * 1.1 * 10^13
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------------------- Mass = 1.1 * 10^16 kilograms.
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- The comet nucleus is 2.5 miles across, but , the Coma head is 3,000 miles across. The tail will keep getting longer but at 367 million miles distance ( April, 2013) it is already 57,000 miles long.
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- At this same point the comet was 460,000,000 miles from the Sun and boiling of material at 51,000 kilograms per minute. 51,000 kilograms of dust and 60 kilograms of water evaporate from its surface every minute. During its travel to passing Earth its temperature increases from 40 Kelvin to 150 Kelvin. As it passes Earth 93,000,000 miles from the Sun it will have lost 0.0004% of its mass. This is assuming the same evaporation rate.
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------------------------- Distance comet traveled = 367,000,000 miles
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------------------------- Speed of travel, 46,800 miles per hour = 13 miles per second.
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------------------------- Rate of evaporation = 51,000 kilograms / minute
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------------------------ Mass = 51,000 * 470,000 = 2.4*10^10 kilograms.
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----------------------- Percent that has evaporated = 2.4*10^10 / 1.1 * 10^16 = 0.0004% of the total mass.
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- If the comet ISON survives its loop around the Sun on its outward path back to the Oort Cloud it will again pass by Mars within 68,000 miles on October 19, 2014. It is estimated that the comet will have lost 10% of its mass by then. That is a guess. Astronomers are anxious to find out. The Mars Reconnaissance Orbiter will be watching. Lord knows what we might learn. Stay tuned, an announcement will be made shortly.
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(1) My brother asked me if the comet would make it around the Sun?
- Her are the calculations. The data for the comet’s trajectory came from 2 spacecraft that are currently orbiting Mars. We turn the spacecraft around to observe the position of the Comet ISON from November 26 to November 30.
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- The answer is the comet will whip around the Sun missing the surface by 652,000 miles.
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- To get this answer we first establish the position of the Sun in x-y coordinates.
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--------------------------- Sun x1 = -.04 y1 = 14.7
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- Next we record the position of the comet in millions of kilometers as it passes by the planet:
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----------------------- x --------------------- y ------------------Distance to Sun
----------------------- -10.5 ----------------- 0.7 ------------------ 17.3
------------------------ -8.8 ------------------ 5.6 ----------------- 12.4
------------------------- -7.7 ------------------ 8.7 ------------------ 9.4
------------------------ -6.3 ---------------- 10.9 ------------------ 7.0
------------------------ -4.6 ----------------- 13.7 ------------------ 4.3
------------------------- +3.2 ----------------- 14.5 ------------------ 3.6
------------------------- +6.6 ----------------- 9.0 ------------------ 9.1
----------------------- +8.0 ------------------ 5.6 ------------------ 12.4
------------------------ +9.3 ----------------- 1.7 ------------------ 16.3
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- Using the Pythagorean Theorem we calculate the distance to the Sun’s center from each point.
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------------------------ (distance )^2 = ( x2 - x1)^2 + (y2 - y1)^2
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- Using the first coordinates x2 = -10.5 and y2 = 0.7
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------------------------ (distance )^2 = ( -10.5 + 0.4)^2 + (+0.7 - 14.7)^2
------------------------ (distance )^2 = ( -10.1 )^2 + ( 14)^2
------------------------ (distance )^2 = ( 102.01) + ( 196)
------------------------ (distance )^2 = 298
------------------------ distance = 17.26 million kilometers ( 10,725,000 miles )
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- Using the last coordinates x2 = 9.3 and y2 = 1.7
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------------------------ (distance )^2 = ( -10.5 + 0.4)^2 + (+0.7 - 14.7)^2
------------------------ (distance )^2 = ( 9.7 )^2 + ( 13)^2
------------------------ (distance )^2 = ( 94) + ( 169)
------------------------ (distance )^2 = 263
------------------------ distance = 16.22 million kilometers ( 10,078,620 miles )
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- Next graph these coordinate points and conned with a smooth parabolic curve. The best fit to this curve is the quadratic equation:
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------------------------- -0.155 x^2 - 0.132x + 16.51
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- To find the maximum peak on the parabola take the first derivative which is the slope of the curve. Then set the equation equal to zero, because the slope goes from increasing to decreasing at the peak and goes through zero slope.
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----------------------- a dx^2 = 2 * a * x * dx
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------------------------ - 0.31x - 0.132 = 0
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------------------------ x = -0.4258
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----------------------- y = -0.155 x^2 - 0.132x + 16.51
----------------------- y = -0.155 (0.181) - 0.056 + 16.51
----------------------- y = 16.43
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- Now calculate the distance to the Sun with these peak coordinates:
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------------------------ (distance )^2 = ( 0.4258 + 0.4)^2 + (16.43 - 14.7)^2
------------------------ (distance )^2 = ( 0.0258 )^2 + ( 1.726)^2
------------------------ (distance )^2 = ( 94) + ( 169)
------------------------ (distance )^2 = 2.989
------------------------ distance = 1.726 million kilometers ( 1,072,486 miles )
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- Radius of the Sun 0.676 million kilometers
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- Distance to the surface of the Sun = 1,050,000 kilometers
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- Distance to the surface of the Sun = 652,440 miles
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(2) Other reviews available upon request:
- #1338 Did comets bring the water to Earth
- #1316 The 5 comets we have visited
- #1292 Using calculus to measure the mass of a comet.
- #629 Star dust - catching a comet’s tail.
- #577 Deep Impact Comet - how we smashed into Comet Temple in 2005 to see what it is made of.
- #549 Comets pummel Earth - Earth strikes back.
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RSVP, with comments, suggestions and corrections. An index of all reviews is available. Some reviews are at: -------- http://jdetrick.blogspot.com
,or: email request for copies to: ------- jamesdetrick@comcast.net
or: ---- “Jim Detrick” ------- www.facebook.com, --------- www.twitter.com
or cell: 707-536-3272 -------------------------- Thursday, November 28, 2013
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