Two Weeks After 2016 June Solstice Earth Reaches 2016 Aphelion

Summary: On Monday, July 4, 2016, two weeks after the 2016 June solstice, Earth reaches 2016 aphelion, Earth’s farthest orbital point from the sun.

Earth’s remoteness (aphelion) and proximity (perihelion) in orbiting the sun: NASA, Public Domain, via NASA Space Place

At 16:24 Coordinated Universal Time (12:24 p.m. Eastern Daylight Time), Monday, July 4, 2016, two weeks after the 2016 June solstice, Earth reaches 2016 aphelion, the farthest center-to-center orbital point from the sun.

The 2016 June solstice happened Monday, June 20, 2016, at 22:34 UTC (6:34 p.m. EDT). The June solstice marks Earth’s axial tilt, at the North Pole, toward the sun and astronomically opens northern summer and southern winter.

Distances between Earth and sun are expressed in astronomical units (AU). In 2012, the International Astronomical Union (IAU) placed the value of 1 AU at 149,597,870,700 meters, equivalent to 149,597,870.70 kilometers or, roughly, 92,955,807 miles.

Retired NASA astrophysicist Fred Espenak places 2016’s aphelion (Ancient Greek ἀπό, apó, “from” + ἥλιος, hḗlios, “sun”) at 1.0167509 astronomical units (152,103, 781 kilometers) from the sun. Time And Date website’s conversion of AU to miles places the point of aphelion in 2016 at 94,512,904 miles.

Espenak gives a mean aphelic distance of 1.0167103 AU (152,097,701 kilometers) for yearly variations in Earth’s farthest center-to-center distances from the sun. July 2016’s aphelion exceeds the mean aphelic figure by 6,080 kilometers.

July 2016’s aphelion bests the previous year’s remoteness by 10,294 kilometers. On Monday, July 6, 2015, at 19:40 UTC (3:40 p.m. EDT), aphelion measured 1.0166821 AU (152,093,487 kilometers). July 2015’s aphelion was 4,214 kilometers less than the mean aphelic distance of 1.0167103 AU (152,097,701 kilometers).

July 2016’s aphelion bests next year’s remoteness by 11,270 kilometers. On Monday, July 3, 2017, at 20:11 UTC (4:11 p.m. EDT), aphelion will measure 1.0166756 AU (152,092,511 kilometers). July 2017’s aphelion will be 5,190 kilometers less than the mean aphelic distance of 1.0167103AU  (152,097,701 kilometers).

The first and last aphelions of the 21st century are closer to the sun than July 2016’s point of aphelion. Both the century’s opener and its closer are also closer to the sun than the mean aphelic distance.

On Wednesday, July 4, 2001, at 13:37 UTC (9:37 a.m. EDT), Earth’s orbit reached aphelion at 1.0166426 AU (152,087,579 kilometers). The 2001 point is 10,122 kilometers less than the mean aphelic distance of 1.0167103 AU (152,097,701 kilometers). Earth’s aphelion in 2016 is 16,202 kilometers farther from the sun than 2001’s aphelion.

Fred Espenak notes the extremes of minimum and maximum perihelions for the 21st century. The interval between the two extremes is 66 years. The range between the century’s minimum and maximum perihelions is 0.0001419 AU (21,225 kilometers).

On Thursday, July 4, 2019, at 22:11 UTC (6:11 p.m. EDT), Earth’s orbit reaches the 21st century’s maximum aphelion. The distance of 1.0167543 AU (152,104,291 kilometers) exceeds the mean aphelic distance of 1.0167103 AU (152,097,701 kilometers) by 6,590 kilometers.

On Wednesday, July 4, 2085, at 21:34 UTC (5:34 p.m. EDT), Earth’s orbit reaches the 21st century’s minimum aphelion. The distance of 1.0166125 AU (152,083,067 kilometers) is 14,634 kilometers less than the mean aphelic distance of 1.0167103 AU (152,097,701 kilometers).

On Tuesday, July 6, 2100, at 15:58 UTC (11:58 a.m. EDT), Earth’s orbit reaches aphelion at 1.0167027 AU (kilometers). The 2100 point is 1,130 kilometers less than the mean aphelic distance of 1.0167103 AU (152,097,701 kilometers). Earth’s aphelion in 2016 is 7,210 kilometers farther from the sun than 2100’s aphelion.

Earth’s orbit around the sun experiences the extremes of closest point (perihelion) and farthest point (aphelion) because of eccentricities, or deviations. Eccentricities, caused by influences such as the moon, account for an orbit that is somewhat elliptical.

A perfectly circular orbit has an eccentricity of zero. Values higher than zero indicate elliptical orbits. The current mean eccentricity of Earth’s orbit is 0.0167.

The takeaway for Earth’s reach of 2016 aphelion two weeks after the 2016 June solstice is that Earth’s eccentrically elliptical orbit drives a yearly maximum point of remoteness that occurs between July 3 and July 7 in the 21st century.

Seasonal variations; solstices signal maximum polar tipping away from or toward the sun: NASA, Public Domain, via NASA Solar System Exploration

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Earth’s remoteness (aphelion) and proximity (perihelion) in orbiting the sun: NASA, Public Domain, via NASA Space Place @ http://spaceplace.nasa.gov/seasons/en/

Seasonal variations; solstices signal maximum polar tipping away from or toward the sun: NASA, Public Domain, via NASA Solar System Exploration @ http://solarsystem.nasa.gov/galleries.seasonal-variations

For further information:

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Available @ http://earthsky.org/tonight/earth-farthest-from-sun-for-year-in-early-july

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Available @ http://earthsky.org/tonight/solstice-brings-northernmost-sunset

Dickinson, David. “Earth at Aphelion 2016.” Universe Today. July 4, 2016.
Available @ http://www.universetoday.com/129513/earth-at-aphelion/#

Erickson, Kristen. “What Causes the Seasons?” EarthSky > Astronomy Essentials > Science Wire > Space. May 3, 2016.
Available @ http://spaceplace.nasa.gov/seasons/en/

Espenak, Fred. “Earth at Perihelion and Aphelion: 2001 to 2100 Greenwich Mean Time.” Astro Pixels > Ephemeris.
Available @ http://www.astropixels.com/ephemeris/perap2001.html

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Available @ http://www.astropixels.com/ephemeris/soleq2001.html

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Available @ http://www.skyandtelescope.com/observing/june-solstice-means-late-nights-bright-lights/

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Available @ http://www.skyandtelescope.com/observing/sky-at-a-glance/this-weeks-sky-at-a-glance-june-17-25/

McClure, Bruce. “Earliest Sunrises Before Summer Solstice.” EarthSky > Tonight. June 12, 2016.
Available @ http://earthsky.org/tonight/earliest-sunrises-before-june-solstice-jupiter-venus

McClure, Bruce. “Latest Dusk for Northerly Latitudes.” EarthSky > Tonight. June 24, 2016.
Available @ http://earthsky.org/tonight/latest-dusk-at-40-degrees-n-latitude

McClure, Bruce. “Slowest Sunsets Around Solstices.” EarthSky > Tonight. June 21, 2016.
Available @ http://earthsky.org/tonight/longest-sunsets-around-solstices

McClure, Bruce. “Solstice Eve Moon Still Near Saturn.” EarthSky > Tonight. June 19, 2016.
Available @ http://earthsky.org/tonight/solstice-full-moon-on-june-20

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Available @ http://www.timeanddate.com/astronomy/perihelion-aphelion-solstice.html

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Available @ http://www.timeanddate.com/calendar/aboutseasons.html