Sep 01

What’s Up in the Sky

What’s Up in the Sky – September, 2014

Close Encounter of the Comet Kind

After having participated in educators’ conferences at the Jet Propulsion Laboratory (through the support of Fennville Public Schools) for the Voyager 2 flybys of Uranus and Neptune, it was with high expectations that I returned to JPL in December of 1999 to witness the touchdown of the Mars Polar Lander on the “Red Planet”.  I will never forget the looks on the scientists’ faces as the signal never arrived and it became increasingly clear that the spacecraft had been lost.

Last January, at the European Space Agency’s Mission Operations Center in Germany, scientists were again anxiously awaiting the signal from a spacecraft.  This time it was the Rosetta spacecraft, due to wake up after more than two and a half years in deep space hibernation.  After waiting 15 minutes one scientist described the mood as “tense factor level 10” and another responded, “it goes to 11”.  Finally, after 18 minutes the signal appeared and the room erupted with much cheering and fist pumping.  It was back!

Launched in 2004, Rosetta became the first spacecraft to rendezvous with a comet on August 6.  For nearly two years it will remain in orbit around the comet (named 67P/Churyumov-Gerasimenko) as it flies past the Sun.  It will study the nucleus and its environment and plant a lander on its surface, another first.

The spacecraft is named after the famous Rosetta Stone discovered almost 200 years ago that led to the deciphering of Egyptian hieroglyphics.  The lander, Philae, is named for the island in the river Nile where an obelisk was found containing an inscription in two languages that enabled Egyptologists to decipher the Rosetta Stone.  Just as these discoveries enabled us to understand ancient Egypt, it is hoped that these spacecraft will give us a better understanding of comets and the early Solar System.

Such a detailed study requires an advanced laboratory and since we can’t bring the comet to the lab, we sent a lab to the comet.  In fact, there are two laboratories on this mission: there are 11 instruments on the orbiter and 10 on the lander.  They will study the gas and dust surrounding the nucleus.  They will take pictures and study spectra.  They will work in a wide range of wavelengths including infrared, ultraviolet, microwave, and radio.  The lander has instruments that will actually drill into the surface and analyze samples.

It is very tricky to pre-plan a comet mission as things change as it approaches the Sun.  We don’t know where and when jets will erupt on the nucleus, or how strong they will be.  Nor do we know where on the surface we will find a spot for the lander.  So mission control will have its hands full this November when it is scheduled to touch down.

So stay tuned for updates on this mission that will further our understanding of what’s up in the sky.

This month in history:
Sept. 01:  Pioneer 11 is first spacecraft to fly past Saturn – 1979
Sept. 03:  Last two Apollo Moon landings canceled by NASA – 1970
Sept. 08:  Voyager 1 launched – 1977
Sept. 10:  Surveyor 5 lands on Moon – 1967
Sept. 21:  Galileo mission ends – 2003
Sept. 23:  Carolyn Herschel discovers NGC 253 – 1783
Sept. 30:  End of daily communication with Pioneer 11 – 1995

Aug 01

What’s Up in the Sky

What’s Up in the Sky – August, 2014

King and Queen at Dawn

August’s best observing is usually the Perseid meteors.  This year, though, the bright Moon will drown out all but the brightest streaks so I recommend a different pre-dawn party this month.

Starting on the morning of August 15th,  pay attention to the two brightest objects above the eastern horizon.  That would be Venus and Jupiter.  Now watch at the same time each morning and you will notice the separation between the two decrease each day until the 18th when they will appear to be less than one half degree apart, a distance roughly equal to the apparent diameter of a full Moon or about half a pinky finger held at arm’s length.  That’s really close for planets!  Five days later the separation will have increased and the two will be joined by a thin crescent Moon making a lovely trio in the pre-dawn sky.

Sunrise is a little before 7 a.m. this time of year so the best time to observe this pairing is between 6 and 6:30 a.m.  The later you look, the higher in the sky they will be but the sky will also become brighter so you will need to find a balance.  Use binoculars if it is too bright out.

Regular readers will know that this is one of my favorite types of observation because you get to witness the motion of objects in space.  All the planets move against the background stars from night to night, but it is difficult to notice unless they happen to appear close to another object such as a star or, as in this case, another planet.  And this time the separation changes a lot each day and is therefore easily noticeable.

Back to the Perseids.  Since the Moon will be bright on the night of August 12, rather than trying to see as many meteors as possible, why not try to see a few really cool bright ones that streak across the entire sky from horizon to horizon.  These are called “earthgrazers” and can last for up to a minute as opposed to regular meteors that streak across in a second or two.  Earthgrazers are meteor that skim through the earth’s atmosphere rather than plunge directly into it.  And early in the evening of a meteor shower is the best time to observe them.

So whether you’re a morning or late night person, there’s good stuff to see this month up in the sky.

This month in history:
August 01: Production of Saturn V rocket ends – 1968
August 06: Mars Science Laboratory rover lands on Mars – 2012
August 12: Echo 1 satellite launched – 1960
August 18: Helium discovered in the Sun – 1868
August 25: Voyager 2 flies past Neptune – 1989
August 28: Galileo spacecraft flies past asteroid Ida – 1993

Jul 01

What’s Up in the Sky

What’s Up in the Sky – July, 2014

Milky Way Cool

Even though it does not get dark until after 10 p.m., next month offers some interesting nighttime viewing.  Several notable events involve the Moon and bright planets or stars.  The first occurs next Tuesday when the crescent Moon will be just below the star Regulus.  Look near the western horizon one hour after sunset.

The action continues four days later when the Moon (which is now just past first quarter) will appear very close to Mars and just to the right of the star Spica.  We’ll come back to Mars and Spica, but first, continue to follow the Moon because two nights later (Monday, July 7) it will be just below the planet Saturn.  Use binoculars if the sky is too bright.

Keep observing Mars and Spica.  Each night the distance between them will become less until Sunday, the 13th when they make their closest approach.
Early risers can continue to enjoy the show on Thursday, July 24, when, 45 minutes before sunrise, you can spot the crescent Moon just to the right of Venus.  Binocs will reveal Mercury to the lower left of Venus.

But July and August really belong to the galaxy – the Milky Way.  In a dark sky, look toward the  southeastern horizon and look for the “Teapot” in the constellation Sagittarius.  Rising up from the spout and arcing all the way across the northeastern sky to the constellation Cassiopeia, is a broad band of light known to the ancients as a heavenly River, a Sky Road, and a Great Path to the world beyond.  We now know, of course, that this band of light is actually composed of the many billions of stars we see as we look toward the center of the Milky Way, our pinwheel-shaped “island  universe” that is home to our solar system as well as all the stars we see in the sky.

It is a somewhat sobering thought that this once majestic jewel of the sky, one that evoked tales of passion and was seen as a path to the hereafter, is now essentially invisible to anyone living anywhere near a city of any size.

The Milky Way was part of the culture and legends of many ancient peoples.  The Algonquins saw the bright stars in the stream as campfires of departed warriors.  The image of the Milky Way, as both the Great Path of life and the River of Heaven, appears frequently in the works of the unrivaled  T’ang dynasty poet Tu Fu.  Norsemen saw the Milky Way as the Path of the slain warriors on their way to Valhalla.

So, no matter what your origins are, you can use the Milky Way  as a guide to what’s up in the sky.

This month in history:
July 03: Harrison Schmitt born – 1935
July 04: Supernova, whose remnant is known as the Crab Nebula, is witnessed – 1054
July 06: Newton’s book, Principia, is published – 1687
July 09: Voyager 2 flies past Jupiter – 1979
July 20: Humans walk on Moon for the first time – 1969
July 25: Svetlana Savitskaya becomes first woman to walk in space – 1984

May 04

What’s Up in the Sky

What’s Up in the Sky – May, 2014

We May Have Showers After Flowers

“April showers bring May flowers” is an old saying that most of us in Holland hope will ring true for Tulip Time. But this year I am hoping for a May shower of a different kind. In fact many astronomers are hoping it will be a storm . . . of meteors.

Most of us are familiar with meteor showers like the Perseids or Leonids, where we sit outside for several hours well into the night and watch for “shooting stars”. If we are able to spot a couple of dozen, it was a good night. But this month we may be in for a real treat.

As many of you know, a meteor shower occurs when the Earth passes through the trail of debris left by a comet after a close encounter with a planet (in this case, Jupiter) or the Sun. Particles ranging in size from dust to small pebbles are released during each passage and continue to follow the comet’s path. The same gravitational forces responsible for the disturbance also tend to”herd” the debris into clumps or streams that continue to orbit the Sun. Next month it is possible that these past dust trails may pile up on one another thus increasing the number of meteors visible.

At this point I must warn you that there are no guarantees in meteor astronomy and estimates range from less than 100 to over 400 meteors per hour. Experts are very cautious with their predictions and often add disclaimers like “rates might be much lower” and “I would not bet on a meteor storm”.

On the positive side, several favorable factors will increase the chance of a good show. There will be no bright Moon to interfere, and the meteors will be unusually slow-moving and are likely to be very bright. And there may be more than one peak of activity, but you will have to be watching between 3-4 a.m. on Saturday, May 24. Hey, just stay up really late Friday night. It’s a long weekend.

If that is too early (or late, as the case may be), the very next morning, Sunday, May 25, look toward the eastern horizon one hour before sunrise for a spectacular pairing of the crescent Moon and Venus. There is no doubt you will be able to see this as long as the weather cooperates.
So, whether high or low, there are good things to see this month up in the sky.

This month in history:
May 5: Alan Shepard becomes first American in space – 1961
May 11: Launch of first geostationary weather satellite – 1974
May 14: Skylab is launched – 1973
May 20: Pioneer-Venus 1 launched – 1978
May 29: First experimental test of Einstein’s General Theory of Relativity performed during total solar eclipse – 1919

Apr 04

What’s Up in the Sky

What’s Up in the Sky – April, 2014

Ever Seen an Occultation?

When I began researching topics for this month’s column, I was excited to see that there will be a total lunar eclipse this month. Unfortunately, you will have to stay up past 4 a.m. in order to witness the whole thing. Not to worry, though, as Mars will put on quite a show and the Moon will occult (pass in front of) several stars. Now, if we can get some clear weather, this could be a good month.

Astronomical observations do not have to be complicated or require expensive equipment. Some of the best events I have observed have been with the naked eye or binoculars and we will have just such an opportunity on the evening of Thursday, April 3. On that date the Moon will pass in front of (occult) several fairly bright stars in the Hyades star cluster.

On the plus side this occultation takes place at a good time and the objects involved will be easy to find. On the minus side it happens near the horizon so we will need an unobstructed view and good weather. That being said, I strongly recommend the use of binoculars and a good clock. The binocs will help you see it and the clock will tell you when to look, which is pretty important.

Go out around 10 p.m. and look due west near the horizon. The crescent Moon should be easily visible between Orion on the left and the Pleiades on the right. Right next to the Moon you should spot a V-shaped group of about five or six stars. Now watch as the Moon approaches the stars, getting closer and closer until, at about 10:15, the star will disappear behind the unlit side of the Moon.

There are two things I like about this observation. First, you are seeing two apparent motions of the Moon – it moves closer to the horizon due to the rotation of the Earth and it gets closer to the star cluster due to its own orbital motion around the Earth. Second, as the separation between the star and Moon decreases, it becomes possible to actually witness the Moon’s motion with respect to the background stars – not an easy thing to see usually.

As for the lunar eclipse, if you plan to be up all night on the 14th, definitely check it out. And yes, Mars is close this month and up all night, but it is only well placed for viewing after midnight. It will be earlier next month.

So this month, the lunar occultation will be your best chance to enjoy what’s up in the sky.

This month in history:
April 2: First photograph of Sun taken – 1845
April 12: Yuri Gagarin becomes first human in space – 1961
April 12: Columbia is first space shuttle to be launched – 1981
April 17: Apollo 13 returns to Earth – 1970
April 20: Shapley-Curtis debate on the distance and nature of spiral nebulae – 1920
April 25: Deployment of Hubble Space Telescope – 1990

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