They [Ulysses and his crew] sail and leave behind Ceuta and Seville, enter the open sea, and turn toward the left... Then he tells us, "in the night I saw all the stars of the other hemisphere" - our hemisphere, the Southern, full of stars. (The great Irish poet Yeats speaks of the "starladen sky." That is untrue in the Northern Hemisphere, where there are few stars compared to ours.)I suppose I could search the answer online, but there must be a reader out there who has lived in both hemispheres, or who has a sufficient knowledge of astronomy to answer the question.
26 December 2015
Are there more stars in the sky of the Southern Hemisphere?
Again I quote from Borges' essay "The Divine Comedy," the content of which was a lecture he gave in Buenos Aires in 1977:
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I left this overnight and no-one has commented, so I'll take a stab at it.
ReplyDeleteI believe the number of individually discernable stars is roughly the same in both hemispheres.
However, what IS true is that the Southern Hemisphere is tilted more towards the centre of the galaxy (which is in Saggitarius), showing more of the bigger and brighter parts of the Milky Way. Plus, there's the Magellanic Clouds.
This difference in the prominence of the galactic cloud of distant, indistinguishable stars might make the Southern Hemisphere sky seem more "full", perhaps producing the illusion of more individually discernable stars even if that's not actually the case.
Thanks, Adrian. When nobody responded to my inquiry, I decided to Google the question, and came up with this apparently reasonable commentary from a New York Times article -
Deletehttp://www.nytimes.com/2014/12/28/opinion/sunday/stargazing-is-better-in-the-southern-hemisphere.html?_r=0
Hi,
ReplyDeleteFrom the article below it appears there are 51.3% stars in the southern celestial sphere visible with the naked eye;
https://www.reddit.com/r/askscience/comments/1rjlhn/can_we_view_more_stars_in_the_northern/
My initial thoughts are that that is only wholly valid standing at one of the poles, as at my latitude of about 52'N I can see Sirius which is a southern hemisphere star, and stood just north of the equator I could see almost all of both.
There might be more interesting stars in the south but I use the north star Polaris too much to give it up easily - out later than expected too often in places we don't really know!
Happy New Year to you and yours.
another phil
I see you got some answers. You got me curious so I looked it up too. Here's what Parade says and it makes sense:
ReplyDeleteMore stars are indeed visible with the unaided eye from the southern hemisphere, but not because more stars exist in that direction of the universe. The reason is that the South Pole is oriented toward the center of the Milky Way, our own galaxy. It’s easier to see those relatively nearby stars than stars that are farther away
http://parade.com/411043/marilynvossavant/are-more-stars-visible-in-south-america-than-north/
I love this quote from the NYT: “In astronomy circles it is often remarked — mostly by envious northerners — that God, in creating the universe, perversely located all the most interesting regions of our galaxy in the Southern Hemisphere, but all the astronomers in the north."
What Geranium quoted from Marilyn vos Savant is generally true, but probably misleading. We do not see (with the unaided eye) stars near the center of the Milky Way, so those do not count except, as Adrian noted, to create brighter areas in the sky.
ReplyDeleteWe see more stars in the southern hemisphere of the sky primarily because the solar system is (currently) "north" of the galactic disc.
Further, it may be significant to the _perception_ of Borges/others that the southern star population is not evenly distributed among the magnitudes (brightnesses). Considering only stars magnitude 2.00 or brighter, 58% are in the southern sky. (Source: Yale Bright Star Catalog version 5, from the Strasbourg Astronomical Data Center) Add to that the bright areas mentioned by Adrian ... oh, and differential clustering by season/right ascension ... more possible calculations ...
Note that due to the Earth's precession, the definition of north changes over a time scale of about 26,000 years. So that can change the population of bright stars a little. Also, although the solar system is currently moving further "north" from the galactic disc, over a time scale of about 70 million years, the solar system is believed to move from "north of" the galactic plane to "south of" it, and back. That movement will change the population of bright stars much more.
But of course, that answer is itself a statistic over time. The galactic disc is neither perfectly flat nor uniformly dense nor static. At a distant time in the future, the dynamics of gas/stellar rotation about the Milky Way and stellar evolution could temporarily put more (visible) stars in northern skies than in southern skies, even while the solar system was "north" of the plane. And eventually our galaxy will "collide" with the Andromeda Galaxy, so that will mess things up...
-WDitot
Sorry, "population" in paragraph 4 should be "distribution".
Delete