Астронет: Астрономическая картинка дня От перигелия до афелия http://variable-stars.ru/db/msg/1748022/eng |
Credit & Copyright: Richard Jaworski
Explanation:
Aphelion
for 2021 occurred on July 5th.
That's the point in Earth's elliptical orbit when it is farthest from the Sun.
Of course, the distance from the Sun doesn't determine the seasons.
Those are governed by
the
tilt of Earth's axis of rotation,
so July is still summer in the north and winter in the southern
hemisphere.
But it does mean that on July 5 the Sun was at its smallest
apparent size when viewed from planet Earth.
This composite neatly compares two pictures of the Sun,
both taken with the same telescope and camera.
The left half was captured close to the date of the
2021 perihelion (January 2), the closest point in Earth's orbit.
The right was recorded just before the aphelion in 2021.
Otherwise difficult to notice, the change in the
Sun's apparent diameter between
perihelion and aphelion
amounts to a little over 3 percent.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.