Neptune
Important facts of Neptune:
Neptune location in the Solar System:
Neptune
is the eighth planet from the Sun to the Solar System. It’s the farthest planet
from the sun till now. Neptune is the fourth-largest planet by diameter, the
third-most-massive planet, and the densest giant planet in the Solar System.
Neptune is 17 times the mass of Earth, slightly more massive than its near-twin
Uranus. Neptune is denser and physically smaller than Uranus because its
greater mass causes more gravitational compression of its atmosphere.
The planet orbits the Sun once
every 164.8 years. Neptune average
distance from the Sun is 2.8 billion miles (4.5 billion kilometers).
Neptune is named after the
Roman God of the sea and has the Astronomical symbol ♆, a stylized version of the God Neptune's trident.
Neptune is not visible to the
unaided eye and is the only planet in the Solar System found by mathematical
prediction rather than by empirical observation. Neptune was subsequently
observed with a telescope on 23 September 1846 by Johann Galle within a degree
of the position predicted by Le Verrier.
Moons of Neptune
Neptune’s largest moon, Triton, was discovered shortly thereafter, though none of the planet's remaining 13 known moons were located telescopically until the 20th century. The planet's distance from Earth gives it a very small apparent size, making it challenging to study with Earth-based telescopes. Neptune was visited by Voyager 2, when it flew by the planet on 25 August 1989; Voyager 2 remains the only spacecraft to visit Neptune. The advent of the Hubble Space Telescope and large ground-based telescopes with adaptive optics has recently allowed for additional detailed observations from afar.
Physical Features of Neptune:
|
Mean Radius |
24,622
km |
|
Equatorial Diameter |
49,244
km. |
|
Circumference
(on Equator) |
155,600
km |
|
Total
Surface Area |
7.6183×109 km² (14.98
Earths) |
|
Mass |
1.02413×10²⁶ kg (17.147 Earths) |
|
Surface Gravity |
11.15 m//s² |
|
Escape
Velocity
|
23.5 km/s |
|
Rotation
Time |
16h 6m
36 s (0.6713 day) |
|
Equatorial
rotation velocity |
2.68
km/s (9,650 km/h) |
|
Orbital
Period |
164.8 Year or 60,182 days or 89,666 Neptunian solar days |
|
Average
Orbital speed |
5.43
km/s or 19,548/hr. |
|
Inclination |
1.767975°
to ecliptic, 6.43° to Sun's equator, 0.74° to invariable plane |
|
Axle
Tilt |
28.32
degree (to orbit) |
Five
Important facts of Neptune
Neptune
Rotation & Revolution
1. Neptune average distance from the Sun is
2.8 billion miles (4.5 billion kilometers).
2. Neptune rotates counter clockwise axis.
3. The Neptune takes 16h 6m 36 s (0.6713 day)
to complete one rotation.
The Neptune rotates counter clockwise
on its axis at a speed of 2.68 km/s (9,650 km/h)
4. Neptune takes 164.8 Year or 60,182 days to
complete one revolution of the Sun.
The Neptune revolves around the Sun and
at a speed of 5.43 km/s or 19,548/hr.
5. The Neptune's axis tilts to 28.32 degree
(to orbit).
Physical characteristics
Neptune is 17 times the mass of
Earth, slightly more massive than its near-twin Uranus. Neptune is denser and
physically smaller than Uranus because its greater mass causes more
gravitational compression of its atmosphere.
Neptune's mass of 1.0243×1026
kg is intermediate between Earth and the larger gas giants. Neptune is 17 times
that of Earth but just 1/19th that of Jupiter. Neptune gravity at 1 bar is
11.15 m/s2, 1.14 times the surface gravity of Earth, and surpassed only by
Jupiter. Neptune's Equatorial radius of 24,622 km is nearly four times that of
Earth. Neptune, like Uranus, is an ice giant, a subclass of giant planet, because
they are smaller and have higher concentrations of volatiles than Jupiter and
Saturn.
Atmosphere of Neptune
Neptune's atmosphere is 80%
hydrogen and 19% Helium at high altitudes. A trace amount of methane is also
present. Prominent absorption bands of methane exist at wavelengths above 600
nm, in the red and infrared portion of the spectrum. Because Neptune's
atmospheric methane content is similar to that of Uranus, some unknown
atmospheric constituent is thought to contribute to Neptune's colour. Neptune’s
atmosphere is subdivided into two main regions: the lower troposphere, where
temperature decreases with altitude, and the stratosphere, where temperature
increases with altitude. The boundary between the two, the Tropopause, lies at
a pressure of 0.1 bars. The stratosphere then gives way to the thermosphere at
a pressure lower than 10−5 to 10−4 bars. The thermosphere gradually transitions
to the exosphere.
Climate
Neptune's weather is characterized by extremely dynamic storm systems, with winds reaching speeds of almost 600 m/s (2,200 km/h; 1,300 mph) nearly reaching supersonic flow. More typically, by tracking the motion of persistent clouds, wind speeds have been shown to vary from 20 m/s in the easterly direction to 325 m/s westward. At the cloud tops, the prevailing winds range in speed from 400 m/s along the equator to 250 m/s at the poles. Most of the winds on Neptune move in a direction opposite the planet's rotation. The general pattern of winds showed prograde rotation at high latitudes vs. retrograde rotation at lower latitudes.
Life
No evidence for life has been
found on Neptune.
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