Solar System
Sun
The Sun is the star at the center of our Solar System. It is a nearly perfect sphere of hot plasma, with internal convective motion that generates a magnetic field via a dynamo process (a naturally occurring electric generator). The Sun is also responsible for the life on Earth. Its diameter is 1.39 million kilometers (864,000 miles), or 109 times the size of the Earth and its mass is about 330,000 time that of the Earth. It accounts for 99.86% of the total mass of the Solar System. Roughly 75% of the Sun's mass consists of hydrogen, and the remaining 25% is of Helium with a mixture of oxygen, carbon, neon, and iron.The Sun today is roughly halfway through the most stable part of its life of approximately 5 billion years.
As of July 2022
Rise and Sets Times (PDT)
Date | Rise Time | Transit Time | Set Time |
|---|---|---|---|
8-Apr | 6:27 | 12:52 | 19:17 |
9-Apr | 6:25 | 12:51 | 19:18 |
10-Apr | 6:24 | 12:51 | 19:19 |
11-Apr | 6:23 | 12:51 | 19:19 |
12-Apr | 6:21 | 12:51 | 19:20 |
13-Apr | 6:20 | 12:50 | 19:21 |
14-Apr | 6:19 | 12:50 | 19:22 |
The Sun is currently in the constellation Capricornus (the Sea Goat) from January 20 through February 16.
Fun Fact: The difference in the distance when the Earth is the farthest from the Sun (aphelion) and when it is closest to the Sun (perihelion) has been determined to be approximately 3.107 million miles (5 million km).
Nautical Twilight Begins: 05:27 hrs. (11-Apr)
Nautical Twilight Ends: 20:15 hrs. (11-Apr)
Moon
Moon and it's current Phase
The Moon is the brightest object in the night sky and has been the source of wonder from the first moments of human first gazed upwards. The Moon was likely formed about 4.6 billion years ago as a result of a huge impact of the Earth and a Mars sized object. The Moon is heavily cratered from impacts resulting from its formation. Over the 29.5 day lunar cycle, the Moon passes through all of its phases from New Moon to Waxing Crescent to First Quarter to Waxing Gibbous to Full Moon to Waning Gibbous to Last Quarter to Waning Crescent back to New Moon. These phases are also depicted in the Moon Phase chart image on this page. During each cycle, the Moon keeps the same face toward Earth. We have been sending spacecraft to the Moon since 1959, the first men walked on the Moon in July 1969 and the last U.S. spacecraft to land on the Moon was Luna 24 in 1976. Lunar eclipses are not rare events, this may happen several times a year (last one occurred this week on June 21). During a total lunar eclipse the Moon takes on a variety of colors, the most obvious being an orange tinge.
Rise and Sets Times (PDT)
Date | Rise Time | Transit Time | Set Time | Age |
|---|---|---|---|---|
8-Apr | 6:23 | 12:57 | 19:36 | 29 |
9-Apr | 6:56 | 13:49 | 20:50 | 1 |
10-Apr | 7:31 | 14:43 | 22:03 | 2 |
11-Apr | 8:12 | 15:40 | 23:15 | 3 |
12-Apr | 8:59 | 16:38 | 0:21 | 4 |
13-Apr | 9:52 | 17:36 | 1:20 | 5 |
14-Apr | 10:51 | 18:32 | 2:09 | 6 |
Times are in Pacific (-7/-8 hrs UTC)
* Indicates sets on the following day.
† Indicates rises on the previous day.
Lunar Cycle Begins March 10 at 10:01 hrs U.T, and ends April 8 at 11:22 hrs U.T.
Lunar Fun Fact: The Moon has only been walked on by 12 persons.
The first man to set foot on the Moon in 1969 was Neil Armstrong on the Apollo 11 mission, while the last man to walk on the Moon in 1972 was Gene Cernan on the Apollo 17 mission. Since then the Moon has only be visited by unmanned vehicles.
Mercury
Not Currently Visible in the sky
Mercury is the closest planet to the Sun, and as such, from the Earth it must be observed in the morning sky when it rises just before sunrise or in the evening sky just after sunset. Mercury is a small planet, its mass is only 5% that of the Earth and the only planet smaller than Pluto. Mercury orbits the Sun quickly, its year is only 88 days. Mercury has no appreciable atmosphere and a surface that is heavily cratered (even more so than the Moon). The day time and nighttime surface temperatures on Mercury can vary ranging from 100 K (−173 °C; −280 °F) at night to 700 K (427 °C; 800 °F) during the day across the equatorial regions.
Rise and Sets Times (PDT)
Date | Rise Time | Transit Time | Set Time |
|---|---|---|---|
8-Apr | 6:31 | 13:07 | 19:42 |
10-Apr | 6:21 | 12:54 | 19:27 |
12-Apr | 6:11 | 12:42 | 19:11 |
14-Apr | 6:01 | 12:29 | 18:56 |
Mercury is currently in the constellation Pisces (the Fish).
Fun Fact: Mercury is the smallest planet in the Solar System
One of five planets visible with the naked eye. Mercury is just 4,879 Kilometres across its equator, compared with 12,742 Kilometres for the Earth.
Nautical Twilight Begins: 05:27 hrs. (11-Apr)
Nautical Twilight Ends: 20:15 hrs. (11-Apr)
May be Visible for viewing in the early morning hours.
Venus
Venus at its greatest brightness is second only to the Moon in the night sky. Venus is shrouded in a thick cloudy atmosphere composed mainly of carbon dioxide and sulphur compounds such as sulphuric acid. This atmosphere produces a greenhouse effect that keeps the surface of Venus at over 700 degrees Kelvin and a pressure of 90 time that of the Earth's atmosphere. Remarkably, several Soviet space craft were able to survive this hostile environment and for a few seconds transmit pictures from the surface of Venus. Like the Moon, Venus goes through very obvious phase changes, making it a favorite object for amateur telescopes and binoculars.
Rise and Sets Times (PDT)
Date | Rise Time | Transit Time | Set Time |
|---|---|---|---|
8-Apr | 5:55 | 11:59 | 18:03 |
10-Apr | 5:53 | 12:00 | 18:07 |
12-Apr | 5:52 | 12:01 | 18:11 |
14-Apr | 5:50 | 12:02 | 18:15 |
Venus is currently in the constellation Pisces (the Fish).
Fun Fact: A day on Venus lasts longer than a year. It takes 243 Earth days to rotate once on its axis (sidereal day). The planet’s orbit around the Sun takes 225 Earth days, compared to the Earth’s 365. A day on the surface of Venus (solar day) takes 117 Earth days.
Nautical Twilight Begins: 05:27 hrs. (11-Apr)
Nautical Twilight Ends: 20:15 hrs. (11-Apr)
Is currently Visible for viewing in the early morning hours.
Mars
Mars is the fourth planet from the Sun, and has a diameter that is roughly half of the Earth. Its Day is a half hour longer than the Earth day and has an approximately a 25 degrees inclination of its polar axis (where Earth has a 23.5 degree inclination). The inclination of the poles gives Mars seasons. The seasonal change in the size of the polar ice caps can be readily observed by Earth based telescopes. Depending on its position relative to the Earth, Mars can appear more than three times brighter than the star Sirius, the brightest in the night sky.
Rise and Sets Times (PDT)
Date | Rise Time | Transit Time | Set Time |
|---|---|---|---|
8-Apr | 4:58 | 10:40 | 16:21 |
10-Apr | 4:54 | 10:37 | 16:21 |
12-Apr | 4:50 | 10:35 | 16:20 |
14-Apr | 4:47 | 10:33 | 16:20 |
Mars is currently in the constellation Aquarius (the Water Bear).
Fun Fact: Mars and Earth have approximately the same landmass. The Martian surface gravity is only 37% of the Earth’s.
Nautical Twilight Begins: 05:27 hrs. (11-Apr)
Nautical Twilight Ends: 20:15 hrs. (11-Apr)
Jupiter
Is currently Visible for viewing in the late evening hours.
Jupiter at its brightest is the third most brilliant object in the night sky, only the Moon and Venus outshine it. The largest planet, it is more massive than all the other planets and Moon combined. Jupiter is composed mainly of hydrogen and helium gas, the same material in the same ratios as the sun. Through a small telescope the bands in the clouds of Jupiter can be detected, as can the persistent storm called the "Great Red Spot". Jupiter has a very fast 10 hour rotation rate, with the equatorial regions rotating slightly faster than those of the poles. In 1994 the many fragments of the comet Shoemaker-Levy 9 bombarded Jupiter leaving bruise colored marks in Jupiter's upper atmosphere that were visible for weeks .
Rise and Sets Times (PDT)
Date | Rise Time | Transit Time | Set Time |
|---|---|---|---|
8-Apr | 7:57 | 14:47 | 18:03 |
10-Apr | 7:51 | 14:41 | 21:31 |
12-Apr | 7:44 | 14:35 | 21:25 |
14-Apr | 7:38 | 14:29 | 21:19 |
The Jupiter is currently in the constellation Aries (the Ram).
Fun Fact: Jupiter is the fourth brightest object in the solar system. Only the Sun, Moon and Venus are brighter. It is one of five planets visible to the naked eye from Earth.
Saturn
Is Currently Visible Visible in the early morning hours.
Saturn is the second largest planet in the solar system behind Jupiter, but it is many amateur astronomer's favorite because of its beautiful ring system. Because of Saturn's equatorial tilt and from the vantage point of the Earth, Saturn's rings slowly but consistently change their appearance, seeming to disappear every 15 years. Like Jupiter, Saturn is a gas giant, but unlike Jupiter we cannot see much color variation in its clouds. Saturn has on large satellite, Titan, which is similar in size to our Moon. There are also four smaller satellites Tethys, Dione, Rhea and Iapetus and several dozen even smaller satellites.
Rise and Sets Times (PDT)
Date | Rise Time | Transit Time | Set Time |
|---|---|---|---|
8-Apr | 5:04 | 10:45 | 16:27 |
10-Apr | 4:57 | 10:38 | 16:20 |
12-Apr | 4:49 | 10:31 | 16:13 |
14-Apr | 4:42 | 10:24 | 16:06 |
The Saturn is currently in the constellation Aquarius (the Water Bearer).
Fun Fact: Saturn is the most distant planet that can be seen with the naked eye. It is the fifth brightest object in the solar system and is also easily studied through binoculars or a small telescope.
Nautical Twilight Begins: 05:27 hrs. (11-Apr)
Nautical Twilight Ends: 20:15 hrs. (11-Apr)
Uranus
Currently Visible in the night sky.
Uranus, the seventh planet from the Sun was discovered by astronomer William Herschel in 1781. At its brightest, Uranus is just barely visible to the naked eye, so it was probably observed before it was discovered as a planet. Uranus is very cold and featureless gas giant. The compounds that give Jupiter and Saturn their color are frozen in the clouds of Uranus so we only see blue-green color from its traces of methane. Uranus has an equatorial tilt of 98 degrees, meaning that it is "barrel-rolling" along its 84 year long orbit about the Sun. The spacecraft Voyager 2 flew past Uranus in 1986 and sent back a wealth of data about the planet.
Rise and Sets Times (PDT)
Date | Rise Time | Transit Time | Set Time |
|---|---|---|---|
8-Apr | 8:02 | 14:55 | 21:47 |
10-Apr | 7:55 | 14:47 | 21:40 |
12-Apr | 7:47 | 14:40 | 21:32 |
14-Apr | 7:39 | 14:32 | 21:25 |
The Uranus is currently in the constellation Aries (the Ram).
Fun Fact: Uranus turns on its axis once every 17 hours, 14 minutes. The planet rotates in a retrograde direction, opposite to the way Earth and most other planets turn.
Nautical Twilight Begins: 05:27 hrs. (11-Apr)
Nautical Twilight Ends: 20:15 hrs. (11-Apr)
Neptune
May be Visible in the early morning hours.
Neptune was predicted before it was seen. Astronomers following the motion of Uranus noticed that it sped up and slowed down. Independently using Newton's laws of gravity, astronomers were able to predict that Neptune would be found in a particular part of the sky. Given the predictions, Neptune was quickly found as predicted. Like Uranus, Neptune is a featureless blue disk and like Uranus most of what we know about Neptune was sent back from the Voyager 2 spacecraft in 1989. Neptune has one large moon, Triton and several smaller satellites.
Rise and Sets Times (PDT)
Date | Rise Time | Transit Time | Set Time |
|---|---|---|---|
8-Apr | 5:38 | 11:35 | 17:32 |
10-Apr | 5:30 | 11:28 | 17:25 |
12-Apr | 5:23 | 11:20 | 17:17 |
14-Apr | 5:15 | 11:12 | 17:10 |
The Neptune is currently in the constellation Pisces (the Fish).
Fun Facts: Neptune is the smallest gas giant. A year on Neptune lasts 165 Earth years.
Nautical Twilight Begins: 05:27 hrs. (11-Apr)
Nautical Twilight Ends: 20:15 hrs. (11-Apr)