When you see pictures of galaxy clusters you see all that matter in the those galaxies and the starts in those galaxies. However, about TWO THIRDS of the actual matter in those clusters is actually in hydrogen atoms located between the stars and galaxies. This does not count all the dark matter which we also know exists.

(The Great Courses – Dark Matter, Dark Energy)

Early in human agricultural history the area around Mesopotamia was rich and excellent farming. Rain usually washes salt deeper into the ground but as an area gets drier the less rain means that salt is built up in the soil and it becomes less productive. This is what happened in parts of the Middle East and continues to happen today in many areas around the world. It is estimated that 1% of the world farming area is made unusable each year due to salt buildup. That is 65,000 acres every day!

(The Great Courses – Understanding Genetics: DNA, Genes and Their Real-World Applications)

The current common view of Nero the emperor is that he was a despot but back in his day there was a certain cult about him. After his death there were at least three people who claimed to be Nero and received some public support at the time.

(The Great Courses – The Emperors of Rome)

There are about 100,000,000,000 stars in each galaxy and there are about 100,000,000,000 galaxies. (That is 100 BILLION for those who don’t want to count all the zeros)

(The Great Courses – Dark Matter Dark Energy)

The ‘Goldberg Variations’ is considered one of many exceptional works by Bach. Each of the 32 ‘variations’ is connected because they all use the same bass line while the more distinctly heard melody is very different for each segment. These were written at a time before the piano when organs and harpsichords had multiple  keyboards and since the fingering for several pieces intertwined each hand Bach intended the performer to use two separate keyboards, one for each hand. Since today’s pianos only have one keyboard the playing of these compositions can be very difficult. The pianist Glenn Gould has recorded two of the more famous renditions of this work and he had a specific piano bench designed for him so that he could sway back and forth to help him while playing.

(The Great Courses – Bach and the High Baroque)

Particle accelerators use the electromagnetic force to accelerate particles. For this reason they can only use charged particles. Neutrons have no charge so they will not be affected by an electromagnetic field. The electric field is used to accelerate a particle and the magnetic field is used to guide the particle. Linear accelerators are very good at moving smaller mass particles. Circular accelerators lose some energy as the move a particle around the curves of a circle but they do a good job with higher mass particles.

(The Great Courses – The Higgs Boson and Beyond)

One of the most powerful women (if not the most powerful) in the history of the Roman Empire was Agrippa the Younger. She was the grand daughter of the emperor Augustus, sister of the emperor Caligula, wife of the emperor Claudius, and mother of the emperor Nero (from her first marriage). Nero eventually had her killed. One of the reasons he may have had her killed was because she prevented him from indulging in his passion for singing, acting and chariot racing due to the fact that they were considered to be occupations for only the lowest class of citizens in the Roman era.

(The Great Courses – Emperors of Rome)

The leaders of the CCP (Chinese Communist Party) wanted to leave Mao behind when they started the ‘Long March’ from a place of great danger in China to one of relative safety from Chiang Kai-shek’s government forces. The CCP was short on cash and Mao had a stash of treasures hidden in a cave that he used to bargain his way onto the March…but he was mostly carried in a litter as most of the leaders were on the ‘March’. Chiang could have easily defeated the CCP at practically any point but he has two motives not to do so. One was that he guided the March through areas still ruled by warlords who were afraid of the CCP so then he could come in and ‘rescue’ them and get them to submit to his authority while moving the CCP to the next location. This way he could consolidate his central authority in China without violence. Chiang’s second motive was that his only legitimate son was being held hostage in Russia. He was hoping to get his son back by not destroying the CCP as a concession to the Russians. (He would eventually get his son back but not until many years later).

(Book – Mao: The Unknown Story – Jung Chang and Jon Halliday)

Eli Whitney may be best known for the invention of the cotton gin but his pioneering of mass production of muskets using  interchangeable parts revolutionized Northern industry during the Civil War.

(The Great Courses – The Skeptic’s Guide to American History)

In early 1933 the Japanese already occupied Manchuria and they then invaded northern China and set up a puppet government called Manchukuo. Japan and China still not want a formal declaration of war at this time. The Russians recognized this new government as legitimate to appease the Japanese to try and keep them from invading Russia. The only other countries to recognize this puppet government were the Vatican and El Salvador.

(Book – Mao: The Unknown Story – Jung Chang and Jon Halliday)