-
2160 - . Each year small changes occur that are
astronomical given time. 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.
-
-
-
---------------------------------- 2160 - Small steps in astronomy. Each year small changes occur that are
astronomical given time. Here are a few
small steps you may not have noticed.
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 lose 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 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 ).
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.
-
- November 10, 2018. 1907 An Index of recent Reviews is available.
----------------------------------------------------------------------------------------
----- 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
--------------------- Saturday, November 10, 2018 -------------------------
-----------------------------------------------------------------------------------------
No comments:
Post a Comment