Earth - Perihelion and Aphelion Calculator

Earth Perihelion and Aphelion Calculator
For the 9799-Year Span From 200 AD to 9998 AD
Built Around the NASA/JPL Horizons API
PHP Program by Jay Tanner

Year Time Zone UTC

Optional Location Label

Double-Click Within Text Area to Select ALL Text

===========================================================================
                EARTH PERIHELION AND APHELION FOR THE YEAR 2025
                ===============================================
                Time Zone UTC+00:00
                

                Dates refer to the modern Gregorian calendar.

===========================================================================
   EVENT    Julian Date UTC   Calendar Date     Time UTC    Dist. AU/mi/km
---------- ----------------- ---------------  -----------  ----------------
Perihelion 2460680.061303796 2025-Jan-04-Sat  01:28:17 PM   0.9833273774820
                                                              91,405,990 mi
                                                             147,103,682 km
                                                  Light Time 00h 08m 10.69s

Aphelion   2460860.329796071 2025-Jul-03-Thu  07:54:54 PM   1.0166437510543
                                                              94,502,941 mi
                                                             152,087,740 km
                                                  Light Time 00h 08m 27.31s
===========================================================================

Event(s) listed may not occur on the same date in another time zone.

Double-Click Within Text Area to Select ALL Text


NOTES:

[1] Occasionally a time-out may occur if the JPL Horizons server
    is temporarily unavailable or too busy and an error occurs.

    If such a crash or hang-up does occur, simply refresh and try
    again.



[2] This Earth perihelion and aphelion calculator spans the 9799
    year period from 200 AD to 9998 AD.

    It was written in PHP 7.4.9 and makes background calls to the
    JPL Horizons API.  If run on a desktop server, it will need a
    connection to the Internet to access the API.



[3] Julian Dates, Day Numbers and Calendar Dates:

    Julian Dates (JD) and Calendar Dates:
    JD <  2299160.5 = Refers to Old-Style Julian Calendar Dates
    JD >= 2299160.5 = Refers to Modern Gregorian Calendar Dates

    Dates up to 1582-Oct-04-Thu refer to the Julian calendar.
    Dates from  1582-Oct-15-Fri refer to the Gregorian calendar.

    The date following 1582-Oct-04-Thu was 1582-Oct-15-Fri, the
    official first date on our modern Gregorian calendar system.

    10 days were dropped from the calendar during the Julian to
    Gregorian calendar transition to bring dates of the seasons
    back into alignment with the sun and the rule for leap year
    was changed to prevent the previous calendar error from re-
    curring.

    Given JD = General Julian Date, then the Julian Day Number
               corresponding to that date on the Calendar is:

               JDNum = floor(JD + 0.5)

    The Julian Day Number is always a positive integer value serving
    as a unique serial number for every date on the calendar and
    holds the calendar date and the day of the week information.

    The Julian Date holds the calendar date and the day of the week
    with the fractional part holding the time of day information.

    For the day of the week (DoW) index corresponding to any Julian
    Date (JD), or Julian Day Number (JDNum), let the day of the week
    be indicated by a numerical index DoW in the range from 0=Sun to
    6=Sat.

    Then:

    DoW = (floor(JD + 0.5) + 1) mod 7
       or
    DoW = (JDNum + 1) mod 7

    Where DoW: 0=Sun, 1=Mon, 2=Tue, 3=Wed, 4=Thu, 5=Fri and 6=Sat

    The JDNum and DoW formulas apply to both the old Julian and
    the modern Gregorian calendar systems.



[4] Standard times are assumed. To adjust for Daylight Saving or
    Summer Time, add 1 hour to the standard times taking care to
    watch for any change of date -OR- subtract 1 hour from the
    time zone offset, which will automatically handle any date
    change.

    For example, the time zone offset for Eastern Standard Time
   (EST) is normally -5 hours. However, when Eastern Daylight Time
   (EDT) is in effect, use a time zone offset of -4 hours instead.
    The computed times will be in EDT and automatically handle any
    date changes.



[5] There is an optional location label that can be applied to the
    computed table for reference.  However, any label should match
    the indicated time zone so as to be accurate and make sense.

    For example, if using the time zone offset for India, putting
   'New York City, USA' as the location, would be rather absurd
    and an inaccurate match between location name and time zone.

    The label can consist of any printable plain-text string and
    defaults to Time Zone Offset +00:00 (Greenwich).



[6] This program implements a cookie to store and recall the year
    and other interface settings between calls. It does not track,
    monitor or perform any other activity. If you navigate away
    and come back later, the interface settings stored in the
    cookie will be recalled from your last visit.

    Each call will refresh the cookie for up to 7 days retention
    unless deleted sooner. There is no harm in deleting the cookie.
    The program will simply revert to the original default values.

View/Copy PHP Source Code

Program by Jay Tanner
Revised: Sunday - September 07, 2025 at 21:09:46 UTC - PHP 7.4.9