Monday will be July 4, celebrated as a birthday – mine, and that of at least one other person I know, and of the U.S. of A. Also on July 4 this year (in other years it can be on July 3 or 5 or 6) the whole Earth celebrates its arrival at aphelion, the outermost point in its orbit around the Sun. Here are the planets’ paths in July, as seen slantingly from 15 degrees north of the ecliptic plane. The Sun is exaggerated 4 times in size, the planets 300.
So why isn’t this the coldest time in the year? Earth’s orbit is not far from circular (though less eccentric than those of Mercury and Mars), and at aphelion we are only about 2,500,000 kilometers farther from the Sun than average. That sounds like a huge distance – 270 times the width of the Earth – but light travels it in 8 seconds; it’s small compared with the 149,500,000 km average Sun-Earth distance, which light travels in about 8 minutes.
Much more influential on our climate is the Earth’s tilt, which has our north pole leaning 23.5° toward the Sun in June.
Mixed metaphor of the week
“A photo of iceberg lettuce heads with $11.99 (£6.80) price tags went viral in recent weeks – leading to a wave of a tongue-in-cheek lettuce memes nodding to rising food, fuel and energy prices.” – Guardian, June 21. Can a virus lead a wave of nodding tongues? Not to mention icebergs, memes, and mixed grammar (“a wave of a”).
We Told You So Department
Britain’s vote to drop out of the European Union is proving disastrous for Britain’s economy, and for other aspects of life such as scientific progress. Defenders of Brexit have stopped talking about the economy; the most they can claim is that we get “freedom” from European standards, and from the European Court of Justice. It dared to rule against Britain’s “appalling” (to quote Prince Charles) scheme of deporting asylum seekers to Rwanda.
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This weblog maintains its right to be about astronomy or anything under the sun.
always good information, accurately. thanks again. i remember the delay in the Apollo missions’ communications broadcasts.
I still remember Prof. Wisdom saying–or do I? I might be conflating things I say with things he said with things he was quoting another professor as saying–that it’s logically possible for a frog to turn into a prince but logically impossible for there to be a married bachelor in the most common meanings of the words in English. Or maybe he was referring to Leibniz’s or others’ ideas about what God can do. I do distinctly remember him quoting another philosophy professor as saying that God “volits” things to happen.
Well, OK, I can change the “in a very narrow sense, he was correct,” to simply “he was correct,” and yet still assert that “for most people, the significant change was the 1999 to 2000.”
Joyous felicitations on this anniversary of your natal day. May it be happy and a prelude to a longer and happier life. Thank you for sharing your knowledge and insights.
I’ve often said the century should change at 2000 also. It is only because of no year 0 (zero). If it were up to me then the BCE years could be negative numbers. Since historians apparently didn’t get the year Jesus was born exactly right, why couldn’t we change that too?
The 1st decade was the years 1 to 10.
The 1st century was the years 1 to 100.
The 21st century is the years 2001 to 2100.
Its first decade was the years 2001 to 2010.
Its second decade was the years 2011 to 2020.
But “the nineteen-sixties” were the years 1960 to 1969.
The “twenty-twenties” are the years 2020 to 2029.
The definition of arithmetical decades is simple, but it our mental grip on it gets slightly confused by the language pattern of “twenties”, “sixties”, etc.
Happy birthday, Guy! On this side of the pond we’re celebrating with fireworks!
I remember reading somewhere that the greater extent of the ocean in the southern hemisphere (as compared to the northern hemisphere) moderates the already modest effect of Earth’s elliptical orbit on our seasons. I just did a quick online search but couldn’t find a reference.
How in a narrow sense was he correct? He was totally, completely, and 100% correct in his statement. People that believed the 1999 to 2000 change was the correct one were totally, completely, and 100% incorrect. There are no two ways about it. I guess you can call me pedantic too.
Curiously, though, I once accused someone else of pedantry. A philosophy professor named Wisdom (yes, that was his name, and he taught formal logic, including to me) said something like, “I don’t understand why people are saying the decade, century, and millennium will end on December 31, 1999. They end on December 31, 2000.” Me: “You’re being pedantic.” Him: “I’m not being pedantic, I’m being correct.” Me: “Pedantic *is* correct.” By which I meant, in a very narrow sense, he was correct, but for most people, the significant change was the 1999 to 2000.
I’m a pedant. I celebrate USA independence on 02 July. That’s the date in 1776 that the Richard Henry Lee resolution was adopted. (“Resolved, That these United Colonies are, and of right ought to be, free and independent States, that they are absolved from all allegiance to the British Crown, and that all political connection between them and the State of Great Britain is, and ought to be, totally dissolved.”) The Declaration of Independence, adopted 04 July, was an explanation of an action that had occurred two days previously. John Adams, at least, expected Independence Day to be celebrated 02 July.
“So why isn’t this the coldest time in the year?”
It is the coldest time in the year!
Yes, in Australia, as I should have said.