Northern Sky

Deane Morrison's "Northern Sky"  -  January 5 - 18, 2019

 
Early and mid-January are great times for star watching because skies are dark, and the winter constellations are bright. It may get a little nippy, but you don’t have to be outside very early, very late, or very long to see the main features.
 
The morning sky is especially good right now because the sun is rising about as late as it ever does. In the southeast, Venus and Jupiter are drawing closer every day, getting ready to pass each other on the 22nd. Venus is the brighter and, for now, the higher of the two. And to complete the predawn picture, the bright red star Antares, the heart of Scorpius, is just to the west of Jupiter.
 
In the evening, the winter constellations are up in the southeast after nightfall. They’re grouped pretty close together, so if you’re not familiar with them, you really should have a star chart to sort them out. But the most recognizable constellation, Orion, is easy to find because of the three stars that form his belt. 
 
Hanging from Orion’s belt is a line of stars that represent his sword. About halfway down the sword, binoculars will give you a glimpse of the sprawling and colorful Orion Nebula. The Orion Nebula is an immense cloud of gas and dust where new stars are forming. It’s about 1300 light-years away, and an estimated 24 light-years wide. Orion is also home to the famous Horsehead Nebula, which you need a telescope to see. But you can find lots of images of the Horsehead Nebula, and the Orion Nebula, online.
 
Orion’s left foot is Rigel, a blue-white star. Rigel and Betelgeuse, the red star at Orion’s right shoulder, are the brightest stars in Orion and among the top 10 in the whole sky. Rigel is a multiple star system, and overall, it’s estimated to be 40,000 times brighter than the sun. Betelgeuse is a gigantic star, estimated at 1,000 times the width of the sun. It’s less than 10 million years old—a mere child—but it’s aged rapidly and is now close to the end of its life. It’s expected to die in a spectacular supernova explosion. That may not happen for a million years, or it could blow up tomorrow.
 
In astronomy news, on New Year’s Day NASA announced that its New Horizons spacecraft, which gained fame by sending back stunning images from Pluto, has just completed what its principal investigator calls “the farthest exploration in the history of humankind.” It performed a flyby of an object in the Kuiper Belt, a doughnut-shaped ring of icy worlds beyond the orbit of Neptune. The object is called Ultima Thule, and it’s 4 billion miles away. The first pictures have just been released, and Ultima Thule looks, in the words of mission scientists, like a reddish snowman, something they’re now sure is the result of two spherical bodies that came together and stuck. Mission headquarters at Johns Hopkins University’s Applied Physics Laboratory says, “the two spheres likely joined as early as 99 percent of the way back to the formation of the solar system, colliding no faster than two cars in a fender bender.”
 
Ultima Thule is 19 miles long, and its two spheres are 12 and 9 miles wide. Scientists hope this object will clear up some mysteries about how our solar system formed. They want to know, for example, how small objects came together to form larger ones, and how they’ve been bombarded by meteor-like objects, although no impact craters are obvious on Ultima Thule.
 
Mark your calendars for Sunday, January 20th, when we’ll have a total eclipse of the moon. The show starts at 9:34 p.m., and I’ll have more on that in the next broadcast. 

Deane is a science writer at the University of Minnesota.
She authors the Minnesota Starwatch column which can be found on the University of Minnesota website at astro.umn.edu.
 

Northern Sky by Deane Morrison
November 24 - December 7, 2018

Deane Morrison is a science writer at the University of Minnesota.        
 
She authors the Minnesota Starwatch column, and in this feature
she shares what there is to see in the night sky in our region.
 
Deane's column “Minnesota Starwatch” can be
found on the University of Minnesota website at astro.umn.edu. 
 

NORTHERN SKY – Deane Morrison
November 10 – 23, 2018
 
Now that we’re back on standard time, the stars come out earlier. That’s good for watching the evening sky. But the morning sun also comes up earlier than it did on daylight time. It rose over Grand Marais at 7:49 a.m. right before the switchover, and it won’t rise that late again till the second half of December. So for now, everybody will have to get out earlier to see the morning show.
 
The star of that show is our old friend Venus. It’s climbing over the eastern horizon as it emerges from a trip between Earth and the sun, and so it’s relatively close and very bright. It starts out as a thin crescent, and through a small telescope or even a pair of very strong and steady binoculars, you can see the crescent getting thicker as the days go by. The star above Venus is Spica, in Virgo. If you go out on only one day, try the 14th, when the planet and the star will be at their minimum distance, just over two moon widths apart. Look about an hour before sunrise.
 
Jupiter will join Venus next month, but right now it's in the process of falling out of the evening sky and getting lost in the sunset. And Saturn is right behind it. In both cases, Earth is going around the sun, leaving those planets behind. In the east, the bright winter constellations are making their annual entrance. However, only a few, like the Pleiades star cluster and Taurus, the bull, are up right after nightfall. If you’re out at that time and looking for something new, you may want to see if you can find some double stars that are up in early evening. Binoculars are highly recommended here.
 
The first double star is easy: it’s at the bend of the Big Dipper's handle. The Big Dipper is now sitting pretty much upright, just above the northern horizon. The double star in the handle is well known, and you can see it without binoculars if your vision is good. While you’re there, you can use the Big Dipper to find Polaris, the north star. The two stars on the bowl of the Big Dipper that are farthest from the handle point toward the north star. Also, try to find the whole Little Dipper. Polaris is at the free end of its handle, and keep in mind that the two "bowl" stars nearest the handle are pretty dim. The second double star is in Taurus. To recap, it's in the east after nightfall. Find the face of the bull, with a star chart if you need one. You'll see the bright star Aldebaran next to the Hyades star cluster, which is shaped like a V. Follow the line of stars from Aldebaran toward the point of the V, and you'll see the double star. Binoculars will help. Use them again on the Pleiades, which appear to the naked eye as a fuzzy patch above Aldebaran. The third double star is the most challenging. Find Vega, a brilliant star in the west, and look just above it for a tight doublet of stars. You’ll definitely need binoculars for that one. And you may want to postpone your search for double stars until after full moon because a waxing or full moon can wash out the dimmer stars in the early-evening sky.
 
Our full moon arrives at 11:39 p.m. on the 22nd, which is Thanksgiving Day. It rises over Grand Marais at 4:28 that afternoon, and for my money, that's when it will be most beautiful. At nightfall, it will be between and just west of Aldebaran and the Hyades, below, and the Pleiades above. 
 

Northern Sky - by Deane Morrison
October 13 - 28, 2018

Deane Morrison is a science writer at the University of Minnesota.        
 
She authors the Minnesota Starwatch column, and in this feature, she shares what there is to see in the night sky in our region.

Deane Morrison’s column “Minnesota Starwatch” can be found on the University of Minnesota website at  astro.umn.edu. 

Norther Sky – by Deane Morrison  -  Sept. 15-28 2018

During the last two weeks of September, we have bright planets in the evening and a couple of regularly scheduled astronomical events.
 
If you face south 40 to 45 minutes after sunset, you’ll see Mars fairly low and still quite bright. Turning a bit westward, you’ll see the Teapot of Sagittarius, with Saturn above it. Next, even lower than Mars, there’s Antares, the red heart of Scorpius. Finally, low in the southwest, we have Jupiter. You probably won’t see Venus, though, especially later in the month, because it’s dropping into the sunset on its next trip between Earth and the sun. That trip also takes it, officially, from the evening to the morning sky.
 
As for stars, the Summer Triangle of bright stars is high in the south after nightfall. And in the west, the brilliant star Arcturus is still pulling its kite-shaped constellation, Bootes the herdsman, down toward the horizon. You might want to compare Arcturus with Vega, the brightest star in the Triangle and see if you can tell that Arcturus is ever so slightly brighter.
 
Now, about those scheduled events. First is the fall equinox. It arrives at 8:54 p.m. on Saturday the 22nd. At that point an observer from space would see the sun poised over the equator and Earth lighted from pole to pole. The equinox is also a crossover time of sorts. In spring and summer, the Northern Hemisphere tilts toward the sun, and the farther north you go, the longer the day length. But after the fall equinox, it tilts away from the sun and the days get shorter as you go north.
 
And, this is the time of year when the Northern Hemisphere is most rapidly shifting its tilt away from the sun. Which brings us to the second scheduled event: the harvest moon. Some say the harvest moon is the full moon closest to the fall equinox, others say it’s the first full moon after the equinox. This one qualifies on both counts. The full harvest moon, on Monday, September 24, rises over Grand Marais at 7:12 p.m., which is just two hours and 40 minutes before perfect fullness, so it’ll be nice and round.
 
But the harvest moon is more than just a name. Here’s how it goes. The full moon occupies a position on the other side of Earth from the sun—so it’s opposite the sun in the sky. Therefore, when we’re tilting most rapidly away from the sun, making it move south and rise later each day, we’re tilting most rapidly toward the full and nearly full moons and making them move north and rise relatively sooner each day.
 
Note that’s relatively sooner. The moon’s orbit makes it rise later from one day to the next; on average, around 50 minutes later. But around the time of the fall equinox, that interval gets slashed because of the moon’s rapid movement up through the northern sky. This year, for a few days centered on September 24, moonrise comes only 24 minutes later each night. That’s the harvest moon effect.
 
It’s fortunate for farmers, because it means that near full moon time, farmers harvesting crops don’t have to wait as long for a bright moon to come up and light their fields.
 
Finally, the rapid change in Earth’s tilt is sapping the day length faster than ever at this time of year, which I’m sure comes as no surprise. We’re losing around three minutes of daylight every day. But, I keep reminding myself, people in places like Alaska and Iceland have to put up with losses of six minutes a day.

Deane Morrison is a science writer at the University of Minnesota.
She authors the Minnesota Starwatch column which can be found on the University of Minnesota website at astro.umn.edu.

She tells us what to look for in the night sky in our region.

NORTHERN SKY – by Deane Morrison                      September 1-14 2018
 
Now that September’s here, the skies are getting seriously dark. Venus is still in the west, but it’s sinking fast. It’s also coming toward us, on the way to zipping between Earth and the sun. If you have a small telescope, you can watch it go through phases. Venus appears as a fat crescent now, but the crescent gets longer and thinner as September goes by. 
 
Somewhat high in the west, we have the brilliant star Arcturus. At this time of year, I like to watch Arcturus slowly fall through the sky from night to night. Arcturus is the brightest star in Bootes, the herdsman, a kite-shaped constellation, and it’s right where the tail of the kite would attach to the sail. So as Arcturus and Bootes drop down toward the horizon, it always seems as if this heavy star is dragging the kite down with it.
 
Actually, Arcturus is falling on a grander scale. It doesn’t orbit horizontally around in the disk of the Milky Way like the sun. Instead, its orbit slices right through the galactic disk. But Arcturus isn’t plunging through the disk by itself; it has more than four dozen stellar companions. Together the group is called the Arcturus stream. One caution: Don’t confuse Arcturus with Jupiter, which is bright but rather low in the southwest after nightfall.
 
Mars and Saturn come out low in the south. Mars is east of Saturn; it’s also brighter and, of course, redder than Saturn. Between the two planets is the Teapot of Sagittarius. Above all this, we have the large Summer Triangle of bright stars. The lowest is Altair, in Aquila, the eagle. It’s pretty much right above Mars. Looking up and a little west of Altair, you’ll see the brightest star in the Triangle. That’s Vega, in Lyra, the lyre of Orpheus. Note the parallelogram of stars below Vega; they outline the lyre and they make a really beautiful sight through binoculars. East of Vega is the third star, Deneb, in Cygnus the swan. Deneb also marks the head of the Northern Cross, a notable feature of Cygnus.
 
The Summer Triangle is a rich area of sky to explore, with both the naked eye and binoculars. And a star chart, if it’s your first time. Look above Altair—again, that’s the lowest star in the Triangle—and try to make out a short and skinny constellation called Sagitta, the arrow. Then try immediately northwest of Sagitta’s feathers and see if you can find the dim but astonishingly realistic Coathanger hanging upside-down. You’ll need those binoculars to make it out. Finally, look to the east-northeast of Altair for Delphinus, the dolphin, which seems to be happily leaping into a dark sea.
 
The moon is new on September 9.  For a couple days before then, there’s a thin old crescent moon in the east before dawn. On Saturday, the 8th, the moon rises close to Regulus, the brightest star in Leo. Then comes Mercury, and the sun right behind it. Look about 40 minutes before sunrise, and good luck seeing all three of the other objects when the sun is so close.
 
And, starting on the 8th, try looking for the elusive zodiacal light in the east, just before the sky starts to get light. The zodiacal light appears as a broad but faint glow along the sun’s path and it comes from sunlight reflecting off the dust that extends far out into space in the plane of the solar system. If you don’t find the zodiacal light on the 8th, the following two weeks will also be good times to look, and the moon won’t interfere with your view of the morning sky. 

NORTHERN SKY – Deane Morrison       Aug. 18-31 2018

At this time of year, the stars and planets have started coming out noticeably earlier. Venus is sinking, but still bright, in the west after sunset. The bright star Spica, in Virgo, is off to the left--our left--of Venus in midmonth. Spica is also dropping toward the western horizon, and it crosses paths with Venus on Friday the 31st. That evening, If you catch them when the sky's dark enough but they haven’t set yet, you’ll see Spica about two and a half moon widths above Venus.
 
Moving east, we have Jupiter, always bright. East of Jupiter and low in the sky is Scorpius, with Antares, the gigantic red star at the heart of the scorpion. Moving east again, we have the lovely Teapot of Sagittarius with Saturn shining above it, and finally Mars. Mars, Venus and Jupiter outshine all the stars, and Mars still outshines Jupiter. But Mars is fading as Earth leaves it behind in the orbital race, and soon Jupiter will reclaim its mantle as the brightest of the outer planets.
 
August's full moon arrives at 6:56 a.m. on Sunday, the 26th. However, the moon sets at 6:07 a.m. that day, so to see it you could go out around 5:30 a.m., or look for it the night before or the night after.
 
In astronomy news, you may have heard that on Sunday, August 12, NASA launched the Parker Solar Probe, an ambitious mission to the one star we can study up close. Parker will fly through the sun’s corona—its outer atmosphere—passing closer to the sun than any previous mission, and University of Minnesota space physicists play an essential role in it. Here’s the scoop.
 
It’s been known for decades that when subatomic particles escape from the sun’s surface their temperature is about 10,000 degrees Fahrenheit. But when they pass through the corona, they get heated to a few million degrees.
 
Scientists have debated how the corona heats these particles so intensely. And also, how the corona accelerates them and spews them out in a torrent of particles that barrels through space at up to a million miles per hour. This stream of particles bathes the solar system and is known as the solar wind.
 
Earth’s magnetic field intercepts the solar wind and shields us against it. When it collides with Earth’s magnetic bubble, it can lead to spectacular auroras. But when it’s fierce, the solar wind can knock out power grids, as it did in Quebec in 1989.
 
Whatever in the corona is heating and accelerating these particles has to be electric and magnetic fields, because that’s all there is. The debate is about the details. The Parker spacecraft carries an instrument, designed by U of M researchers, to study the corona’s electric and magnetic fields and particles. This data will help settle the debate and make it easier to predict the heaviest gusts of the solar wind and take precautions to protect power grids.
 
How close will Parker get to the sun? If Earth and the sun were at opposite goal lines on a football field, the closest any spacecraft has come is the sun’s 29-yard line. But Parker will zip inside the 4-yard line, less than four million miles from the sun. NASA has dreamed of such a mission for 50 years, but the technology took time to develop. For example, engineers had to design a heat shield that’s capable of deflecting temperatures high enough to melt steel. Also, the Parker Solar Probe must, by itself, adjust its orientation to keep its heat shield between the spacecraft and the sun as it hurtles through its tightest loop around the sun at more than 400,000 miles per hour.
 
 
 

Deane Morrison is a science writer at the University of Minnesota.

She authors the Minnesota Starwatch column, and in this feature she shares what there is to see in the night sky in our region.
Deane's column can be found on the University of Minnesota website at astro.umn.edu.

Deane Morrison is a science writer at the University of Minnesota.

She authors the Minnesota Starwatch column, and in this feature she shares what there is to see in the night sky in our region.
Deane's column can be found on the University of Minnesota website at astro.umn.edu.

Northern Sky  -  by Deane Morrison  June 9-22 2018

During the two weeks between June 9 and 22 the moon switches from the morning to the evening sky. It starts out as a waning crescent that drops diagonally toward the sun from morning to morning. On the 13th we get a new moon, at which point the moon crosses to the evening sky and begins waxing.
 
In the western evening sky, Venus continues to outshine everything else. Starting on the 9th, the Gemini twins, which have been dropping toward Venus, start to pass the planet on the right, or, its northern side. The Gemini twin stars are Castor and Pollux, Pollux being the one closer to Venus. On their way toward the horizon, the twins pass the young moon on its way up.  
 
We can see this after nightfall on Friday, the 15th. We’ll have a young crescent moon below Venus and the Gemini twins off to the side. When the sky has darkened on the 16th, grab your binoculars and look for the lovely but subtle Beehive star cluster midway between Venus and the moon. You’ll see two stars bracketing the Beehive to the upper left; these are the Aselli, or asses. In Latin the Beehive is called Praesepe, the manger, and the Aselli are two donkeys feeding at it. On the 19th, the Beehive will appear immediately southeast of Venus, that is, just to its lower left, but by then we’ll have a nearly first-quarter moon that might wash out the stars a bit.
 
Jupiter is up in the south after nightfall. To the west of Jupiter is the bright star Spica, in Virgo. Actually, it’s the only bright star in Virgo. Above these two objects is Arcturus, in Bootes, the herdsman, a kite-shaped constellation. Just east of the kite is Corona Borealis, the northern crown, which looks like a tiara hanging in the sky. Its brightest star is Alphecca, or Gemma, the jewel in the crown. Alphecca is a double star, a pair of stars, one significantly fainter than the other. It’s an example of what’s known as an eclipsing binary. Every 17.4 days, the fainter star passes in front of the brighter star as seen from Earth and causes a slight dip in Alphecca’s brightness. The most famous eclipsing binary is Algol, in the winter constellation Perseus. The variations in its brightness are easily seen. To the ancients it looked like a winking eye in the sky.
 
If you’re up late, camping or just outside with a southern exposure, you can watch the summer stars follow Jupiter into the sky from the southeast. First Scorpius and its gigantic red heart, Antares. Then the Teapot of Sagittarius, with Saturn shining above the lid of the Teapot, and finally Mars, which is brightening by the day. Everything rises earlier every night, but practically speaking, you won’t see Mars till after midnight.
 
The summer solstice happens at 5:07 a.m.—almost exactly sunrise in Grand Marais—on Thursday, the 21st. At that moment the sun reaches a point over the Tropic of Cancer and Earth will be lighted from the Antarctic Circle up to the North Pole and over to the Arctic Circle on the night side of the planet. You may have noticed that the sun is about as high as it gets for about a month before and after the summer solstice. And about as low as it gets for two months centered on the winter solstice. That’s because, of course, the sun moves northward and southward most slowly around the solstices, when it changes direction and appears to stop for a while. In fact, the word solstice is derived from the Latin for “sun standing still.”

Deane Morrison is a science writer at the University of Minnesota.
She authors the Minnesota Starwatch column, and in this feature, she shares what there is to see in the night sky in our region.

"Minnesota Starwatch" can be found on the University of Minnesota website at 
astro.umn.edu.