He was 100% correct in his estimate of the Sun’s size. His result was that the Sun was more than 27 times the size of the Earth. This is correct. He did not say how much more than that, because his technique is extremely sensitive to error (basically, taking the tangent of an angle very close to 90º).
Another major factor was screwing up his units of measurement. A Persian astrologer, Al-Farghani, had done a pretty good study on the size of the Earth and had estimated the circumference was 20,400 miles. His work had been published in Europe and Columbus was familiar with this figure.
What Columbus didn’t realize was that Al-Farghani was using Arabic miles, which are approximately 2160 meters. Columbus assumed the measurement was in Roman miles, which are approximately 1480 meters.
So Al-Farghani had written that the circumference of the Earth was the equivalent of 44,060 kilometers. But Columbus was thinking the distance was the equivalent of 30,190 kilometers. (The actual figure is 40,075 kilometers.)
If you assume the Earth is flat, then the difference in sun angle at noon on the summer solstice between Syene and Alexandria would correspond to the sun being 4000 miles above Syene at that date and time. 
And imagine what Plato could have done if he hadn’t stuck away half a pint of whiskey every day.
Not to mention spending all that time at his retreat.
I liked that on Crash Course in the episode of Slavery or the one about the Civil War, he has his “me from the past” pointing at the alleged states rights as being the cause of the civil war, John Green humorously mention his former high school teacher telling him then: “state’s right to what, sir?”
A nice way to highlight the absurdity of the states’ rights argument in the context of slavery. And a different high school teacher than in your case.
That reminds me of Apu taking his citizenship examination which went something like this:
Proctor: What were the causes of the Civil War?
Apu: The causes were varied, including state’s rights, representation in the federal government, the economic disparity between the …
Proctor: Just say slavery.
Apu: Slavery it is, sir!
More about, but not entirely. The Lincoln administration had bent over backwards to avoid presenting the war as a crusade to abolish slavery, which would probably have lost the Union the war. Although much was made of the Emancipation Proclamation both at the time and since, all it did was declare that the states still in rebellion as of the deadline would have their slaves confiscated. It was as much to appease critics who complained it was contradictory to uphold the institution that was the casus belli of the rebellion. And it was hoped just the threat might encourage the rebels to lay down their arms. Even then it really was just a formalization of the Union policy of declaring any slave escaped of a rebel master who made the Union lines was henceforth “contraband”, as subject to forfeiture as any cattle or horse. Though it probably did sway British sentiment against recognition of the CSA some. The Thirteenth Amendment of course was what really destroyed slavery, enough to forestall any motivation for further rebellion.
True. To start, it had to be about Uniting the Union, (and punishing the traitors). Later it became those things AND freeing the slaves.
Adding to the point is the fact that one of the chief complaints of the South was that Northern states were, in accordance with their own laws, recognizing runaway slaves as free people. The South wanted the federal government to overrule those states and send the slaves back home.
Then, once they formed the Confederacy, they included a provision preventing any individual state from abolishing slavery; entirely contrary to individual state sovereignty.
States’ rights, indeed.
The constitution did provide for enacting fugitive slave laws which the federal government had the authority to enforce. What happened was that as resistance to empowering slavery grew in the North, the slave states agitated for and got a new Fugitive Slave Act in 1850 replacing the one that had been on the books since 1793. The newer law was blatantly biased in the slave owners’ favor.
In “Mississippi Burning”, FBI agent Gene Hackman responds similarly.
It’s an attempt to elevate the atrocity of slavery to a principled cause.
Like a bank robber insisting that his crime is actually about gun rights.
“Gun rights to do what?”
And I was having trouble finding it, found it, It is this episode:
Hi I’m John Green; this is Crash Course US History and today we discuss one of the most confusing questions in American history: What caused the Civil War?
Just kidding—it’s not a confusing question at all. Slavery caused the Civil War.Young Green: “Mr. Green, Mr. Green, but what about, like, states’ rights and nationalism, economics—?”
John Green: Me from the past: In your senior year of high school, you will be taught American Government by Mr. Fleming, a white Southerner who will seem to you to be about 182 years old. You will say something to him in class about states’ rights.
And Mr. Fleming will turn to you and say,
“A state’s rights to what, sir?”And for the first time in your snotty little life, you will be well and truly speechless.
The CSA did make each state more sovereign. But their constitution and reasons for leaving the Union was mostly slavery. Ir was 90% slavery.
They did mention a few other things they were p.o.'d about, but yeah 90% slavery.
t was 100% about slavery and issues attendant to slavery i.e. most of the Northern states refusing to enforce the Fugitive Slave Clause (something that is explicitly noted in “A Declaration of the Causes which Impel the State of Texas to Secede from the Federal Union”. The five states that adopted and published declarations of causes (Georgia, Mississippi, South Carolina, Virginia, and Texas) all repeatedly mention slavery and grievances related to the Northern opposition to the ownership and trade of slaves. There is no other issue that is noted either within these declarations or elsewhere within contemporary historical writings such as territorial borders or agricultural/mineral rights for which the Southern states were inclined to secede from the Union. The claims that “We did it for ‘states rights’” or because of tariffs and so forth are post hoc rationalizations that came along with the “Lost Cause” that only gained real traction in the 1890s and later.
Stranger
No, the declarations you cite do mention a few minor causes besides slavery; so tariffs, etc. weren’t really the cause of secession but they weren’t completely made up after the war either. They were only increased in emphasis during the Lost Cause era.
There is no mention of tariffs in any of those declarations of the five states list, and only brief and vague mentions of “commercial restrictions, of protection, of special privileges, of waste and corruption in the administration of Government” and similar sophistry, but there are eighty-four distinct mentions of the term “slavery” or “anti-slavery” with a running thread of grievance through each about how unfair it is for the other states to enforce their mores on the Southern slave-owning states, and especially poor Texas which did nothing wrong other than tilt the balance toward slavery, never minding that that by the time that Texas joined the United States in 1845, the trans-Atlantic trade in African slaves had been prohibited for over a quarter of a century and nearly every European and South American nation had formally abolished the slave trade and had or was in process of forbidding the ownership of slaves.
The American Civil War was completely about slavery and issues pertaining to slavery. There was no other common issue of contention that would have caused eleven state–all pro-slavery–to band together into a confederacy to secede from the United States, that the five states noted in the previous post were very explicit about their reason for doing so.
Stranger