Neptune is the eighth and farthest known planet orbiting the Sun. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times the mass of Earth. Compared to Uranus, its neighbouring ice giant, Neptune is slightly smaller, but more massive and denser. Being composed primarily of gases and liquids, it has no well-defined solid surface. Neptune orbits the Sun once every 164.8 years at an orbital distance of 30.1 astronomical units (4.5 billion kilometres; 2.8 billion miles).
Neptune completes its first orbit since its discovery on September 23, 1846
Neptune is the eighth and farthest known planet orbiting the Sun. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet.
Historical Significance
Neptune is the eighth and farthest known planet orbiting the Sun.
Events Before
New FINA rules re competition swimsuits come into effect; all body-length swimsuits banned; men's suits to maximally cov
New FINA rules re competition swimsuits come into effect; all body-length swimsuits banned; men's suits to maximally cover from the waist to knee, and women's from shoulder to knee; fabric must be a "textile" or woven material
Earthquake devastates Haiti, killing an estimated 100,000 to 160,000 people and destroying the majority of the capital P
Earthquake devastates Haiti, killing an estimated 100,000 to 160,000 people and destroying the majority of the capital Port-au-Prince
"Easy Rider" director and actor Dennis Hopper (73) divorces his fifth wife Victoria Duffy due to irreconcilable differen
"Easy Rider" director and actor Dennis Hopper (73) divorces his fifth wife Victoria Duffy due to irreconcilable differences and out-of-control spending
Infanta Elena, Duchess of Lugo (46) divorces Lord of Tejada, Jaime de Marichalar (46) after 15 years of marriage
Infanta Elena, Duchess of Lugo (46) divorces Lord of Tejada, Jaime de Marichalar (46) after 15 years of marriage
Alexandre Bilodeau wins the gold medal in the freestyle skiing men's moguls event, becoming the first Canadian to win go
Alexandre Bilodeau wins the gold medal in the freestyle skiing men's moguls event, becoming the first Canadian to win gold during an Olympic Games hosted in Canada
Events After
Actress Parminder Nagra files for divorce from photographer James Stenson due to irreconcilable differences after 3 year
Actress Parminder Nagra files for divorce from photographer James Stenson due to irreconcilable differences after 3 years of marriage
American actor Dick Van Dyke (86) weds second wife, American make-up artist Arlene Silver (40) in Malibu, California
American actor Dick Van Dyke (86) weds second wife, American make-up artist Arlene Silver (40) in Malibu, California
"Twilight" actor Peter Facinelli (38) divorces "Beverly Hills 90210" actress Jennie Garth (39) due to irreconcilable dif
"Twilight" actor Peter Facinelli (38) divorces "Beverly Hills 90210" actress Jennie Garth (39) due to irreconcilable differences after 11 years of marriage
Actress and model Heidi Klum (39) divorces British soul and R&B singer-songwriter Seal (49) due to irreconcilable differ
Actress and model Heidi Klum (39) divorces British soul and R&B singer-songwriter Seal (49) due to irreconcilable differences after almost seven years of marriage
"The Lion King" becomes highest grossing Broadway show, overtaking "The Phantom of the Opera"
"The Lion King" becomes highest grossing Broadway show, overtaking "The Phantom of the Opera"
More from the 2010s
New FINA rules re competition swimsuits come into effect; all body-length swimsuits banned; men's suits to maximally cov
New FINA rules re competition swimsuits come into effect; all body-length swimsuits banned; men's suits to maximally cover from the waist to knee, and women's from shoulder to knee; fabric must be a "textile" or woven material
10 people are killed, and 120 are injured in a stampede in Luanda, Angola
10 people are killed, and 120 are injured in a stampede in Luanda, Angola
Dutchman Michael van Gerwen wins his first PDC World Darts Championship, defeating Peter Wright of Scotland 7-4; it is t
Dutchman Michael van Gerwen wins his first PDC World Darts Championship, defeating Peter Wright of Scotland 7-4; it is the first time no Englishman has been in the final
Lithuania adopts the euro as its currency, replacing the Litas and becoming the 19th member of the Eurozone
Lithuania adopts the euro as its currency, replacing the Litas and becoming the 19th member of the Eurozone
Frequently Asked Questions
- What happened on July 11, 2011?
- Neptune is the eighth and farthest known planet orbiting the Sun. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times the mass of Earth.
- Why is Neptune completes its first orbit since its discovery on September 23, 1846 significant?
- Neptune is the eighth and farthest known planet orbiting the Sun.