-
-
- On average 170 new comets are discovered each year. 60 were discovered in 2012. 27 of these were discovered by amateur astronomers, many using simple binoculars.
When will the big one likely hit?
-
- The Apollo size comets are in the range of 100,000 metric tons.(10^14 grams).
- When is one of this size likely to hit Earth?
-
- Use our equation from the log-log plot in Review #1611: The mass for the Apollo size comet is 10^14 grams.:
-
---------------------- y = -0.9 ( mass) - 1.6
--------------------- mass in log form for 10^14 is 14
-
--------------------- y = -0.9 ( 14) - 1.6
-------------------- y = - 12.6 - 1.6 = - 14.2
-
-------------------- y = log of number of impacts = log of -14.2
-------------------- anti- log to get the number of impacts = 10^ -14.2
-
--------------------- number of impacts = 6.31 * 10^-15 km^2 / year
-
- The surface area of the Earth is 5.1*10^8 square kilometers.
-
---------- number of impacts = (6.31 * 10^-15 km^2 / year) * (5.1*10^8 km^2)
---------- number of impacts = 3.2*10^-7 / year
-
- Expected 3.2 impacts every 10,000,000 years
-
- Expected 1 impact every 3,125,000 years.
-
- Earth is expected to get hit by a 100,000 ton comet every 3 million years on average.
-
---------------------------------------------------------------------------------------------
-
- Repeating the same calculation using the exponential equation rather that the straight line equation on the log-log plot.
-
---------------- number of impacts = 0.025 * ( mass)^-0.9
---------------- number of impacts = 0.025 * ( 10^14)^-0.9
---------------- number of impacts = 0.025 * ( 10^-12.6)
---------------- number of impacts = 6.28*10^-15 per km^2 per year
---------------- number of impacts = (6.28*10^-15 per km^2 per year) * (5.1*10* km^2)
---------------- number of impacts = (3.2 * 10^-7 per year)
---------------- 3.2 impacts in 10,000,000 years
-
------------------ One impact in 3,125,000 years, same answer.
---------------------------------------------------------------------------------------------
-
- On average we have only a year from the time a new comet is discovered before it passes closest to Earth, or hit's us. Typically we have seven of these close encounters each year.
-
- Passing close is defined as being within 31,000,000 miles.
-
- For comparison:
- The Moon is 238,855 miles away.
- The Sun is 93,000,000 miles away
- Venus is 25,000,000 miles away
- Mars is 48,000,000 miles away.
-
- There were nine comets that flew by in 2012 only one of those was within the 31,000,000 mile range.
-
--------------- Discovery ------------- Distance in million miles ----- Fly-by ------
-
---------------- October, 2011 ----------------233 ------------------ June, 2012 ---
---------------- June, 2011 --------------------307 ------------------ June, 2012 ---
---------------- March, 2011 ------------------186 ------------------ August, 2012 ---
---------------- September, 2011 -------------205 ------------------ September, 2012 ---
---------------- September, 2010 -------------521 ----------------- September, 2012 ---
---------------- May, 2012 --------------------214 ------------------ October, 2012 ---
---------------- June, 1827 ---------------------79 ------------------ October, 2012 ---
---------------- May, 2012 --------------------223 ------------------ November, 2012 ---
---------------- May, 2011 ---------------------31 ------------------ December, 2012 ---
-
- The average number of months between discovery and flyby is 12 months.
-
- 1/9 of these came within 31,000,000 miles. That is 11%.
-
- The total number of comets discovered in 2012 was 60 . . If 11% of these are flybys within the 31 million miles then 7 close encounters occurring last year.
-
- Here is the data for the past 14 years:
-
-------------------------- Year --------------- Total new comets discovered --------------
-
------------------------- 2012 -------------------------------- 60 ------------------------
-------------------------- 2011 ------------------------------- 49 ------------------------
------------------------- 2010 ------------------------------- 161 ------------------------
------------------------- 2009 ------------------------------- 227 ------------------------
------------------------- 2008 ------------------------------- 220 ------------------------
------------------------- 2007 ------------------------------- 223 -------------------------
------------------------- 2006 ------------------------------- 206 ------------------------
------------------------- 2005 ------------------------------- 221 -------------------------
------------------------- 2004 ------------------------------- 223 -------------------------
------------------------- 2003 ------------------------------- 193 -------------------------
------------------------- 2002 ------------------------------- 182 -------------------------
------------------------- 2001 ------------------------------- 149 -------------------------
------------------------- 2000 ------------------------------- 135 -------------------------
------------------------- 1999 ------------------------------- 129 --------------------------
-
- In 2012 45% of the new comets discovered were by amateur astronomers using simple binoculars.
-
- Over the 14 years 18% were detected by amateur astronomers. 74% detected by spacecraft and 8% by observatories.
-
- A meteorite found in this Sahara desert in 2012 came from the crust of Mars. It is estimated to be 4,000, 000, 000 years old.
-
- It weighs 1.37 pounds.
-
- Science theorizes that the chunk of Mars crust was chipped away by an asteroid impact. It was blown off into space and eventually made its way to Earth, landing in Morocco's desert.
-
- The total amount of meteorites collected and identified as Martian is 300 pounds.
-
- The largest Moon meteorite ever found weighed 4 pounds.
-
Most meteors burn up in the atmosphere before reaching the ground. Most of the others land in the oceans that cover 70% of Earth’s surface.
-------------------------------- -----------------------------------------------------------
(1) Other Reviews:
# 1611 Comet impacts.
# 1557 Tektites
# 719 Geminid Meteors
# 547 Shooting Stars
# 1017 Comets
# 1019 Sudbury Asteroid.
-----------------------------------------------------------------------------------------------
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 ------------------------------- Tuesday, December 3, 2013
-------------------------------------------------------------------------------------------------
No comments:
Post a Comment