-
-
----------------------------- 1907 - Small steps in astronomy
-
- There are a lot of things happening in the Universe that you may not be noticing. These are slow changes and our human senses are just to crude to measure.
-
- This past year the rotation of the Earth slowed down. This slowing is caused by the friction of the tides and the constant tug of the orbiting Moon. The time of a single rotation ( one day ) , has increased 14 nanoseconds this past year , 2016. That might not sound like much ( 0.0000000014 seconds ), but in 4 million years from now we will loose our leap years. By then the year will be exactly 365 days.
-
- This slowing of the Earth’s rotation has another effect in the Earth-Moon system. There is the law of “ the Conservation of Angular Momentum”. The Earth and the Moon both spin on their axis as the Moon revolves around the Earth. To make Angular Momentum constant as the Earth spin slows down the Earth-Moon distance is increasing. The Moon is leaving us by about 2 centimeters per year ( one inch ).
-
- Also, this past year the Sun got hotter. This average temperature increase is not enough to cause ‘global warming’. It amounts to an increased luminosity of 5 billionths of a percent each year ( 0.000,000,005% ) That doesn’t sound like much either, but, that would mean the Sun has increased temperature and luminosity by 25% over the past 4 billion years.
-
- What is causing this is that the Sun is fusing fuel faster as it gets hotter. Today it is loosing 10^17 kilograms of mass per year ( 100,000,000,000,000,000 kilograms according to E=mc^2). In another 2 billion years the Sun will be hot enough to boil off the Earth’s oceans.
-
- 2 billion years after this happens the Sun will expand into a planetary nebula leaving a white dwarf cinder behind at the core. Bigger stars will explode in to supernovae. There is 1% to 2% chance that a supernova will go off in our Milky Way Galaxy this next year. We can expect 2 to 7 supernova to be occurring in our Galaxy per century. Most we can’t see, but, two have been seen with the naked eye, Tycho’s Supernova in 1572 and Kepler’s Supernova in 1604.
-
- This past year stars have not only exploded and died, some new stars have formed. In our region of the Orion Nebula a new star slightly smaller than our Sun is born each year Star formation in our Galaxy is estimated to be 0.68 Solar Mass per year. But, that is an average per year. It could vary from 100 Solar Mass per century to 5 very low-mass stars per year. Star formation is a gradual process taking millions of years.
-
- While all this is happening the overall Universe is expanding and cooling down. Today the temperature is 2.725 Kelvin above absolute zero. Absolute zero Kelvin is the coldest temperature possible where all molecular activity ceases.
-
- This temperature is now measured in the Cosmic Microwave Background radiation after 13.8 billion years of cooling. This background radiation continues to cool with continuing expansion separating the galaxies. This year it went 200 picoKelvin cooler (2*10^-10 Kelvin ). (That is 0.000,000,000,2 Kelvin.) You probably didn’t notice.
-
- Another thing happened with the expanding Universe. We lost another 20,000 stars that expanded so far away their light will never reach us. At that some 15 billion lightyears distance the galaxies are receding faster than the speed of light. In fact, all the galaxies that are the Observable Universe today are only the remaining 3%. The other 97% are so far distant their light will never get here. Each year another 20,000 become unobservable in this way.
-
- These are small steps each year that become astronomical. Tiny steps repeated can make a big difference in the long run. A quote to live by.
-
- July 16, 2019
- --------------------------------------------------------------------------------------
---- Comments appreciated and Pass it on to whomever is interested. ----
--- Some reviews are at: -------------- http://jdetrick.blogspot.com -----
-- email feedback, corrections, request for copies or Index of all reviews
- to: ------- jamesdetrick@comcast.net ------ “Jim Detrick” -----------
- https://plus.google.com/u/0/ -- www.facebook.com -- www.twitter.com
----- 707-536-3272 ---------------- Tuesday, July 16, 2019 -----
------------------------------------------------------------------------------------------
No comments:
Post a Comment