Waxing moon closer to Jupiter on January 20

That dazzling starlike object close to the moon on January 20, 2013 is the giant planet Jupiter. You can’t miss this pair in clear skies this evening, no matter where you are on Earth. And they are still getting closer. Tomorrow’s conjunction of Jupiter and the moon will be visible from around the globe, and particularly dazzling for the Americas, where it’ll be the closest these two will appear in our sky until the year 2026.

The image at the top of this post is from EarthSky Facebook friend Janet Furlong in Culpeper, Virginia. She took this photo last night (January 19, 2013). The two brightest objects are the moon and Jupiter. View larger. Janet wrote:

Step outside and lift your head up and view the sky. Totally gorgeous … so much to see tonight.

What motions of the moon and Jupiter cause them to come together this way in our sky? Their most noticeable motion, in course of a single night, is that the moon and Jupiter go westward across the sky. They do so for the same reason that the sun goes westward during the day. It’s because the Earth rotates from west-to-east on its axis, causing the sun, moon, planets and stars to appear to move from east to west on a daily basis.

Get ready for January 21 moon-Jupiter conjunction with these awesome photos

Meanwhile, from tonight to tomorrow night, you will see the moon move closer to Jupiter on the sky’s dome. That change will be caused by a true motion of the moon itself, its motion through space in orbit around Earth. Due to its orbital motion, the moon travels about 13^oeastward in front of the backdrop stars every day. For reference, the moon’s diameter equals one-half degree.

Jupiter changes its position in front of the background stars, too. Yet, in contrast to the moon, it does so at a snail’s pace and sometimes erratically. Jupiter’s true motion is more difficult to make out than that of the moon because Jupiter orbits the sun, not the Earth. Because we view Jupiter from the moving platform of Earth, Jupiter appears to move backwards in its orbit for about four months. Really, this motion is an illusion, called retrograde motion. Jupiter has been moving in a retrograde fashion – westward in front of the stars – for some months now. It will end its retrograde motion, becoming temporarily stationary in front of the stars, on January 30.

Believe it or not, Jupiter’s orbital speed (13 kilometers/second) is much faster than the moon’s (1 km/second). Keep in mind, though, that far-distant Jupiter takes nearly 12 years to circle the sun in its great big orbit. On the other hand, our moon circles the Earth in its tiny orbit in less than four weeks. That’s why, as seen from Earth, the nearby moon appears to travel more swiftly than the distant planet Jupiter.

By the way, unlike the stars, the moon and Jupiter don’t shine by their own light. They shine by reflecting the light of the sun.

Bottom line: Look for these two brilliant beauties – the moon and the planet Jupiter – close together for several nights around January 21, 2013. As seen from the U.S. and Canada, this is the closest the waxing gibbous moon and the giant planet Jupiter will appear until the year 2026. Their close proximity on the sky’s dome wil be visible throughout the world, but particularly dazzling for the Americas.

January 2013 guide to the five visible planets

Earth passes between Jupiter and sun on December 2-3, 2012

Today Earth passes between the sun and Jupiter, placing Jupiter opposite the sun in our sky. Astronomers call this event an opposition of Jupiter. The 2012 opposition is Jupiter’s closest until 2021. Jupiter shines more brightly than any star in the night sky. It is in a region of the sky filled with bright stars, near the bright star Aldebaran in the constellation Taurus.

Taurus? Here’s your constellation.

The clocks in Austin, Texas, say the opposition is tonight at 8 p.m. on December 2. Yet, according to Universal Time – the standard clock time at the meridian of 0^o longitude – the opposition of Jupiter happens at 2 a.m. on December 3. The opposition happens at the same instant worldwide but at different clock times.

For the fun of it, we also show the asteroid Vesta’s place in front of the constellation Taurus on the feature chart at top, because this world will be at opposition and closest to Earth on December 9, 2012. More than likely, you’ll need an optical aid, a dark sky and a good sky chart to see Vesta. The moonless nights accompanying the Geminid meteor shower on December 12, 13 and 14 should be great spotting the asteroid Vesta (possibly even with the unaided eye).

How do I translate Universal time into my time?

But for now, we return our focus on Jupiter, the largest world in our solar system. It shines well over four thousand times more brightly than the asteroid Vesta.

Jupiter comes to opposition every 13 months or so, as Earth takes this long to travel once around the sun relative to Jupiter. Jupiter’s closest approach to Earth for the year always falls on or near this planet’s opposition date. In 2012, Jupiter came nearest to Earth on December 1, at 15 hours Universal Time (9 a.m. Central Time). Then Jupiter was only 378 million miles (609 million kilometers) away. Because Jupiter passed its perihelion – or closest point to the sun – in March 2011, the giant planet is now getting farther from the sun. As a result, at this opposition, Jupiter is as close as it will be until the year 2021.

And, because it’s opposite the sun around now, you can see Jupiter at any time of night. For example – as today’s chart shows – you can see it in the south at midnight tonight, when the sun is below your feet. At dawn tomorrow, you’ll see Jupiter low in your western sky. At opposition, Jupiter shines at its brightest in our sky.

You would need at least 80 Jupiters — rolled into a ball — to be hot enough inside for thermonuclear reactions to ignite. In other words, Jupiter is not massive enough to shine as stars do. But Jupiter is the largest planet in our solar system. So when the sun goes down on this early December night, you might — if you’re fanciful enough — imagine bright Jupiter as a tiny sun all night long.

Bottom line: Be sure to look for Jupiter on the night of December 2-3, 2012, the night of Jupiter’s opposition. The planet shines in front of the constellation Taurus, very near the brightest star in Taurus, Aldebaran. This opposition of Jupiter brings Earth’s closest encounter with Jupiter until the year 2021!

Image Credit: Jupiter is bright! It will be shining more brightly than any of the surrounding stars. This photo of Jupiter is from November 18, 2012. It’s from EarthSky Facebook friend Carlos Colon Sr.

Do missing Jupiters mean massive comet belt?

Two nearby planetary system have vast comet belts, but no Jupiter-like planets. Are those two things related?

Astronomers have discovered vast comet belts surrounding two nearby planetary systems known to host only Earth-to-Neptune-mass worlds, according to a November 27, 2012 ESArelease. They determined that the systems – called GJ 581 and 61 Vir – must have at least 10 times more comets than in our own solar system’s Kuiper Belt.

The planets in both systems are known as ‘super-Earths’, covering a range of masses between two and 18 times that of Earth. Interestingly, however, there is no evidence for giant Jupiter- or Saturn-mass planets in either system.

The gravitational interplay between Jupiter and Saturn in our own solar system is thought to have been responsible for disrupting a once highly populated Kuiper Belt, sending a deluge of comets towards the inner planets in a cataclysmic event that lasted several million years.

Dr. Mark Wyatt from the University of Cambridge is lead author of a paper focusing on the debris disc around 61 Vir. He said:

The new observations are giving us a clue: they’re saying that in the solar system we have giant planets and a relatively sparse Kuiper Belt, but systems with only low-mass planets often have much denser Kuiper belts.

We think that may be because the absence of a Jupiter in the low-mass planet systems allows them to avoid a dramatic heavy bombardment event, and instead experience a gradual rain of comets over billions of years.

Dr. Jean-Francois Lestrade of the Observatoire de Paris led the work on GJ 581. He said:

For an older star like GJ 581, which is at least two billion years old, enough time has elapsed for such a gradual rain of comets to deliver a sizable amount of water to the innermost planets, which is of particular importance for the planet residing in the star’s habitable zone.

The astronomers used ESA’s Herschel space observatory for the new study

Bottom line: Astronomers have discovered vast comet belts surrounding two nearby planetary systems called GJ 581 and 61 Vir. They determined that the systems must have at least 10 times more comets than in our own solar system’s Kuiper Belt. The planets in both systems- are known as ‘super-Earths’, covering a range of masses between two and 18 times that of Earth. Interestingly, however, there is no evidence for giant Jupiter- or Saturn-mass planets in either system.

Read more from ESA

Image Credit: Artist impression of the debris disc and planets around the star known as Gliese 581, superimposed on Herschel PACS images. The black oval outline sketched onto the Herschel data represents the innermost boundary of the debris disc; the approximate location of the outermost boundary is represented by the outer set of dashed lines. Image credit: ESA/AOES

Earth and Jupiter will be closer on December 1, 2012 than until 2021

Jupiter is always closest around the time of its yearly opposition, which comes on December 2-3, 2012. Jupiter will remain close and bright throughout December and January 2013

In 2012, Jupiter – largest planet in our solar system – will come nearest to Earth on December 1, at 15 hours UT (9 a.m. Central Standard Time). Then Jupiter will be only 378 million miles (609 million kilometers) away from us – still very, very distant – but closer than it will be again until the year 2021.

Why is Jupiter especially close in early December 2012? Jupiter comes closest to Earth once each year, when our planet flies between Jupiter and the sun. Earth will fly between the sun and Jupiter next on December 3 at 2 UT. That is 8 p.m. Central Standard Time on December 2. We’ll go between the sun and Jupiter in early December, and that movement of Earth will place Jupiteropposite the sun in our sky – in other words, rising in the east as the sun is setting in the west.

When it is opposite the sun, astronomers say that Jupiter is inopposition to the sun. Jupiter comes to opposition once every 13 months or so, because Earth takes a year to orbit the sun, in contrast to Jupiter’s 12-year orbit. Our orbit is closer to the sun than Jupiter’s. Plus we move faster in orbit than Jupiter does. Earth travels at a speed of about 18 miles per second in orbit, in contrast to about 8 miles per second for Jupiter

Image Credit: Jupiter, its Red Spot, its banded atmosphere, and two of its moons in this view taken by the Voyager 1 spacecraft from about 20 million kilometers (12 million miles) away. Each moon is about the size of Earth’s moon. Meanwhile, Jupiter could hold more than a thousand Earths. The visible moons here are Io (left), in front of the Red Spot, and Europa (right).

November 2012 guide to the five visible planets

November 2012 presents all five visible planets, although only Jupiter and Venus are clearly visible all month long. Mars appears but briefly after sunset, and the planets Mercury and Saturn before sunrise.

Only two planets are easily visible throughout November 2012: Jupiter andVenus. Jupiter is moving into prime time, rising in the east-northeast about two hours after sunset in early November and around sunset by the month’s end. Once Jupiter rises, this dazzling world will light up the sky for the rest of the night. In contrast, Venus rises in the east-southeast about three hours before sunrise in early November and about two and one-half hours before sunrise in late November. Be sure to see the conjunction of Venus and the ringed planet Saturn on the morning of November 26!

If you missed seeing the moon close toJupiter on the nights of November 1 and2, you’ll have another chance in late November. Watch the moon and Jupiter shine together all night long on November 28.

If you missed the moon and Venus in the predawn and dawn sky on November 9,10, 11 and moon below Venus and next to Saturn before sunrise Monday, 12, try again at dawn on December 10 and 11.

Easily locate stars and constellations during any day and time with EarthSky’s Planisphere.

The other three visible planets – Mercury,Mars and Saturn – never drift far from the sun’s glare this month. Mercury passes into the November morning sky just after mid-month and will put on a good morning performance (for the Northern Hemisphere) in the final week of November and the first two weeks of December. Mars remains an evening object all month long, though this faint world appears low in the southwest sky after sunset and sets around nightfall.Saturn returns to visibility in the morning sky around the time of the Leonid meteor shower. If you’re diligent, you should be able to catch all five visible planets this month.

Mars may be the hardest visible planet to catch in November. Let the waxing crescent moon guide you to Mars after sunset on November 15 and 16. Circle these dates on your calendar, so you don’t miss out!

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Photo Credit: The planet Jupiter is always bright, but in late November and December 2012 it’s at its brightest. That’s because Earth will pass between Jupiter and the sun on December 2. Jupiter is the brightest object in this wonderful photo byEarthSky Facebook friend Carlos Colon Sr. Thank you, Carlos!

Pleiades, Jupiter and moon parade in November 2 evening sky

From around the world tonight, the Pleiades star cluster rises over the eastern horizon first, followed by the dazzling planet Jupiter and then the waning gibbous moon. They all climb above the east-northeast horizon fairly early this evening at mid-northern latitudes, but rather late this evening at southerly latitudes in the Southern Hemisphere.

But no matter where you live, you’ll find Jupiter between the moon and the Pleiades cluster this evening. If the moonlit glare makes it difficult to see the dipper-shape Pleiades cluster, try looking at this beautiful group of stars with binoculars. Once the trio – the Pleiades, Jupiter and the waning gibbous moon – climbs above the horizon this evening, it’ll be out all night long.

Pleiades: Famous Seven Sisters

The moon is displaying a waning gibbous phase right now, so it’s rising well after darkness falls. Because the waning moon rises an average 50 minutes later every night, the moon will probably come up after your bedtime in a day or two – if it hasn’t already. Are you an early riser? If so, look for the waning moon to adorn the morning sky for the next ten days or so.

In the meantime, Jupiter will remain in front of the constellation Taurus the Bull for months to come. Moreover, this constellation – the radiant of the November Taurid meteor showers – will rise four minutes earlier each evening, or two hours earlier each month.

Taurus? Here’s your constellation

EarthSky’s meteor shower guide for 2012

Orion’s Belt to star Sirius, plus moon, Jupiter, Venus

Sure, we’ve said it before. But we’ll say it again, because it’s one of the neatest tricks in all the heavens. That is … Orion’s Belt points to Sirius. Sirius is the brightest star in the sky. It’s up before dawn now but will be shifting into the evening sky as the months pass. And if you’re out before dawn tomorrow morning – September 10, 2012 – you can’t fail to see a spectacular sight in the predawn sky. The moon will be in between the sky’s brightest planets, Venus and Jupiter.

Orion is found in the predawn morning sky every September, but the planet Jupiter’s presence to the north of the Hunter is special to September of 2012. Also, the presence of the waning crescent moon to the north of Orion also happens tomorrow on September 10, 2012. Venus is brighter than Jupiter – and closer to the eastern horizon before dawn.

The phases of the moon recur on or near the same calendar dates in cycles of 19 years, so look for a similarly-sized waning crescent moon to return to this place in the starry sky on September 10, 2031. Mark your calendars! :-)

The two bright objects in the east before dawn are Venus and Jupiter. Here they are on June 27, 2012 from Mark E. White II in Itabirito, a small town in the Minas Gerais state of Brazil. Venus is brighter and closer to the horizon. Notice the Pleiades star cluster, also called the Seven Sisters, above the planets. These planets can be seen from around the world. The moon will sweep near them in mid-July 2012.

July 2012 guide to the five visible planets

We’re getting many questions about the two bright planets in the east before dawn in July 2012. They are Venus and Jupiter. Read more below.

Four planets are out all month long in July 2012. You’ll find two in the evening sky and the other two in the morning sky. Look for Mars and Saturn in the west as soon as darkness falls. Plus Mercury is near the sunset as the month begins. Look for Venus and Jupiter, the sky’s brightest and second-brightest planets, respectively, in the eastern predawn darkness and morning twilight. While the evening planets Mars and Saturn are dimming, the planets Venus and Jupiter are brightening as we speak. We’ll talk first about the morning planets and then the evening planets.

Look here for more great photos of Venus and Jupiter before dawn

Morning planets: Jupiter and Venus

Venus and Jupiter rise well before the sun in the morning sky. People around the world are seeing them and marveling at their brightness. If you haven’t seen them yet, you are really missing out on a fine morning attraction, and the best is yet to come. Venus will reach its greatest brilliancy as the morning “star” near mid-July 2012, around the time the moon sweeps through this part of the sky. And Jupiter will be brightening all month long.

Greatest illuminated extent for Venus July 12, 2012

Both morning planets shine in front of the constellation Taurus throughout the whole month of July. Taurus’ gorgeous Pleiades star cluster makes a nice straight line with Venus and Jupiter, with the Pleiades residing at top and Venus at bottom. If you look closely, you can see the dipper-shaped Pleiades in the beautiful photo by Mark E. White II, above.

Look for Venus to swing closest to Aldebaran, the ruddy eye of Taurus the Bull, on July 9. Look for Jupiter to pass by Aldebaran at July’s end.

For a real treat, get up early to see the waning crescent moon joining up with Venus and Jupiter on the mornings of July 14, 15 and 16.

April 2012 guide to the five visible planets

April 2012 provides another great month for watching planets! Four of the five visible planets – Jupiter, Venus, Mars and Saturn – come out at nightfall. Mercury rises in the east before sunrise.

April 2012 presents another great month for watching the five visible planets. In fact, four of them –Jupiter, Venus, Mars and Saturn – will be visible at nightfall for most of the month from both the Northern and Southern Hemispheres. The missing planet – Mercury – will be extremely difficult to view from the Northern Hemisphere, as it sits in the glare of morning twilight. But for the Southern Hemisphere, Mercury’s apparition as the morning “star” couldn’t be much better, because the solar system’s innermost planet rises in the east well before the onset of dawn in that part of the world

Image taken April 1, 2011 by EarthSky Facebook friend Lyle Evans in California. Thank you, Lyle!