En la superficie de Mercurio amanece por el este y anochece por el oeste, como en la Tierra. Pero una vez al año, cuando pasa por el perihelio, el movimiento orbital sobrepasa el lento rotar del planeta y ese día el devenir del Sol en su cielo se interrumpe. En ese punto de su órbita es cuando se pueden contemplar tan extraños atardeceres. La estrella se detiene completamente en el cielo mercuriano y se mueve hacia atrás para retornar a su camino normal a medida que desciende la velocidad del planeta al desplazarse en la órbita.
This is the translation:
The Sun on Mercury’s surface rises in the east and sets in the west, as on Earth. But once a year, when it passes through perihelion, the orbital motion overtakes the slow rotation of the planet and on that day the Sun’s path across its sky is interrupted. It is at this point in its orbit that such strange sunsets can be seen. The star comes to a complete stop in the Mercurian sky and moves backwards to return to its normal path as the planet’s speed slows as it moves through its orbit.
It’s a good question though: does Mercury’s 3:2 tidal lock to its orbit precess along with the orbital axis or not?
Or when Jupiter was thought to be a giant terrestrial planet with a solid surface, albeit under a thousand-mile deep atmosphere.
Interesting random fact: in the first book of C.S. Lewis’s space trilogy, the natives of Mars refer to the planets by names ending in -andra; but in the third book the terrestrial planets keep their -andra suffixes but the energy beings/angels refer to Jupiter and Saturn without the -andra. As if they know better that they’re not solid bodies? (Or astronomical thought on the subject changed between the writing of the books).
Mercury’s 3:2 lock is a resonance between its synodic day and its apsodal year. The mechanism behind it wouldn’t have any reason to care about anything sidereal.
I dunno… A tidally locked planet is kind of interesting, I guess, but I think that a tidal resonance is even more so.
And a planet that was on its way to being tidally locked, and almost got there, except that it got caught up on a resonance between its rotation and another planet, is even more interesting. That’s what happened to Venus: Whenever she’s closest to Earth, she always shows the same face to us.
(Oh, and to explain the resonances: Both Mercury and Venus are slightly elongated in shape. Whenever Mercury is closest to the Sun, and the tidal forces are therefore strongest, it has its long axis pointed along the line to the Sun, but flipped in the opposite direction each orbit. And whenever Venus is closest to Earth, and therefore the tidal forces from Earth are strongest, its long axis is pointed towards us.)
Evolution never rewards that degree of genetic similarity. It always punishes it. It’s just that the punishment is random, and just hasn’t – quite - finished hitting cheetahs, yet. At any given moment, they could potentially be on their last generation before complete extinction, if the wrong disease strikes.
OK - now this is getting interesting!
Lukcy Starr was the first performer of this classic hit (written in 1959. The last Lucky Starr Space Serial ended in 1959 when approaching The Snows Of Pluto.
Obviously he was trying to tell people of his travels, but they would not believe him.
Also, the first american version of the song (which topped the US charts) was performed Hank Snow.
I’m probably being dumb and missing something obvious but… what is astonishing about being able to see one country (especially a mountain) from another country?
On the average, 95.7% of the people on a commercial flight plane that crashes survive, so about eight times as many people die in crashes of this kind of aircraft as on most commercial flight aircraft.
Today my wife and I flew on the small American discount airline, Avelo, that may be the only alcohol-free carrier based outside an Islamic nation. The airline does not have any drinks service, although they give away bottles of spring water.
It was announced at the start of our Sarasota - Wilmington Delaware flight today that the flight was both smoking and alcohol free. AFAIK this is standard for the airline.
Many of their flights originate from small airports where there is no opportunity to buy alcohol, or anything else liquid, after passing through the security screening. The difference with the Sarasota flight was that you could buy alcohol after TSA, thus apparently necessitating the announcement.
Another unusual feature of this airline is that they do not have a frequent flier program. I’m guessing that one isn’t so unique, but maybe it is.
