Don’t you just hate perihelion?

By Phil Plait | January 2, 2008 6:00 pm

If you can guess what line I twisted for the title, and from what movie, you win nothing.

But either way, you do win a front row seat to the Sun! The Earth arrived at perihelion on January 3 at midnight Universal Time (it probably wasn’t exactly at midnight, but that’s the accuracy listed at the US Naval Observatory website), which was an hour ago as I post this. Perihelion is when the Earth is closest to the Sun on its elliptical orbit (which only marginally affects the seasons).

The distance to the Sun at perihelion is about 147 million kilometers, and at aphelion — the farthest distance, duh — is about 5 million km farther out. You won’t notice the giant Sun looming down on us, of course, since the change in distance is pretty small, so the size of the Sun only changes about 3% over six months.

No eggs will stand on end, no forces vast and mysterious will reverse themselves, and no prophecies will finally come to fruition. Perihelion is just something cool, and now you know we’re there.

By the way, I would have posted this earlier today, but sometimes even astronomers get confused over the whole "midnight in England is earlier on the day before here in the US" thing.

CATEGORIZED UNDER: Astronomy, Cool stuff

Comments (24)

  1. Blaise Pascal

    Happy Anomalistic New Year!

  2. bigjohn

    Perihelion!! I predict that the Sun will appear to be as big as the full Moon!

  3. Michael Lonergan

    If we are at the closest point to the Sun in our orbit now, and it is summer south of the equator, does that mean that summer at say 49 degrees South, is hotter than summer at 49 degrees north latitude, when we are further from the sun?

  4. gopher65

    Yup Michael, at the moment summer is hotter in the southern hemisphere than in the northern. But I think it reverses itself every 7000 years or so because of precession. Or is that every 14000? I don’t remember. Something like that about some dizziemedoodle idea …. or something.

  5. Michael Lonergan

    Never mind. I just read the link you posted.

  6. Shoeshine Boy

    Cool! My birthday is the same day as perihelion.

    I r special :)

  7. If we’re so close to the sun, why am I freezing my butt off? Obviously this is some sort of hoax perpetrated by the Chinese.

  8. BA Fan

    Isn’t today Jan 2? According to US Naval Observatory, Perihelion is Jan 3 at 20 UT (5pm ET). Still time for that last minute shopping.

  9. At USNO the time is listed as “00”, or midnight UT. That’s 7:00 Eastern, or 5 Mountain, on January 2.

  10. Wednesday, January 2, 2008
    Perihelion – Earth is closest to the sun
    (19:42:48) Perihelion – Earth is closest to the sun.


  11. That would be Eastern time

  12. Gavin Flower

    In the Southern Hemisphere we may be closer to the Sun, but we are moving faster in this part the Earth’s orbit… does that make our Summer shorter???

  13. Gavin Flower says: “In the Southern Hemisphere we may be closer to the Sun, but we are moving faster in this part the Earth’s orbit… does that make our Summer shorter???”

    In a word, yes. The southern hemisphere gets the worst of both worlds; the summers are shorter and hotter while the winters are colder and longer. But as Phil has explained elsewhere, the temperature has more to do with the ocean/land ratio than the distance to the sun.

    – Jack

  14. Redx

    but… eggs will stand on end. Most people try it on the equinox, but eggs will still stand on end.

  15. cope

    “Don’t you just hate…Illinois Nazis?” from “Blues Brothers would be my guess.

    Should I be correct, please send my large container of nothing to nobody@nothing.nowhere.


  16. Rick

    i thought it was homer saying “don’t you just hate pants?” in a simpsons episode.

  17. “Don’t you just hate Perry’s wife?”

    C’mon, didn’t anybody see Arthur?

  18. Eric

    Wow, this morning I opened up a new carton of eggs, and to my utter amazement, all 12 eggs were standing on end!!!!

    What could this mean? What could this possibly mean???

  19. Joshua: I’ll alert the media. You are correct.

    It’s not the first time I’ve quoted “Arthur”, either. It’s a fantastically funny movie.

  20. Doc

    My favorite Arthur quote is still:

    “Don’t you wish you were me? I know I do.”

  21. You have an explanation about that anomalistic precession:

    This phenomenon is independent from solstice/equinox precession. However, it plays a minor role in “Milankovic cycles” (the oscillations between ice ages and inter-glacial ages in a “Icehouse Earth”…).

    Anyway, Happy Anomalistic Year to Everybody.

  22. Troy

    I think the most conspicuous aspect of perihelion is that you get later sunsets.

  23. zemig

    Shouldnt perihelion coincide with winter solstice?

  24. zemig types:

    [[Shouldnt perihelion coincide with winter solstice?]]

    Why? The length of day as opposed to night does depend on where Earth is in its orbit (and the obliquity of the equator), but I don’t think that cycle is tied to perihelion/aphelion in any way. Is it? Dr. Plait?


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