Jun 06

What’s Up in the Sky

What’s Up in the Sky – June, 2015

Sailing by Light

Wouldn’t it be nice if we could travel to other planets on a ship that requires no fuel tanks, no thrusters, no complex motors, pumps, wiring, or tubing? How about a spacecraft that can operate on solar energy alone, and I don’t mean solar panels powering electric motors.

In fact, it has already been done. In May of 2010, Japan launched the IKAROS (Interplanetary Kite-craft Accelerated by Radiation Of the Sun) spacecraft on a mission that would take it to Venus and then continue in orbit around the Sun. And on May 20, the Planetary Society successfully launched LightSail, a prototype craft designed to test the feasibility of using solar radiation for not only propulsion, but also navigation.

But let’s back up a minute and look at the concept of solar sailing. Light consists of packets of energy called photons and, although they have no mass, photons have momentum. When they strike a shiny surface, a lot of their momentum is transferred, giving the surface a small impulse or push. The force is tiny but it is constant and a small force pushing for a long time can create a large change in velocity.

The Planetary Society’s LightSail (www.planetary.org) uses a new type of miniature spacecraft called CubeSats. CubeSats are cubes, 10 cm on a side, that can be combined to form larger spacecraft. LightSail consists of three such units stacked together measuring 10 by 10 by 30 centimeters, about the size of a loaf of bread.

Hitching a ride on an Atlas V rocket whose prime payload is a classified USAF mission, LightSail is currently orbiting Earth but has not yet unfurled its sails. That will happen after four weeks of thorough testing of all its avionic and electronic systems. After the waiting period the sails will be deployed and the spacecraft will be propelled by solar radiation. The downside is that this will greatly increase the atmospheric drag, causing the spacecraft to reenter the atmosphere in about a week.

This is all in the plan, however, as this is a test flight, designed to gather data and “shake down” all systems. The second mission, scheduled for a 2016 launch, will be aboard SpaceX’s new Falcon Heavy rocket which will take it to a higher orbit (almost 450 miles) where it will not be as greatly affected by Earth’s atmosphere. It is hoped that this will lay the foundation for possible interplanetary or even interstellar missions in the future.

Finally, I hope you have been following Venus and Jupiter in the western sky after sunset. You won’t want to miss their close encounter on the evening of June 30 when they will be the “stars” of everything up in the sky.

This month in history:
June 3: Gemini IV astronaut, Ed White, takes America’s first space walk – 1965
June 8: First unpowered glide test of X-15 – 1959
June 10: Mars rover “Spirit” launched – 2003
June 16: Valentina Tereshkova first (and only solo) woman in space – 1963
June 18: Sally Ride becomes first American woman in space – 1983
June 22: Evidence of liquid water on Mars announced by NASA – 2000
June 30: Tunguska impact flattens hundreds of miles of Siberian forrest – 1908

May 03

What’s Up in the Sky

What’s Up in the Sky – May, 2015

Close Encounters of the Planetary Kind

By now, everyone reading this column knows about the evening planets Venus and Jupiter. For several months Venus has dominated the western sky after sunset. Lately Jupiter can be found nearby, high in the southwest, but it’s closing in on its brighter companion.

In fact, over the next three months, the celestial highlight will be the convergence of Jupiter and Venus. This is the perfect event for the casual observer with no equipment as well as the seasoned veteran amateur astronomer anxious to log a rare conjunction.

So, start now. Find a spot with a clear view of the western horizon (or as close as possible) and go out about an hour after sunset to familiarize yourself with the players in this drama.

Start with Venus, bright in the west, and Jupiter, higher up and to the left (toward the south) of Venus. If it’s not too late and you have a clear horizon, you should be able to see Orion’s belt due west. Look straight up from that to find the Gemini twins, Castor and Pollux, about half-way between Venus and Jupiter. If you draw a line starting at Venus through Jupiter and a little beyond, you will find the star Regulus in the constellation Leo, the Lion.

Use these objects in the following weeks to track the progress of the planets as the separation between them decreases steadily until, on the night of June 30, they will appear to be closer than the width of the full Moon! That’s why you want to start noticing these guys now, so on June 30, you can look at them and say, “. . . now that’s cool! I remember when they were way far apart.”

There is another advantage to making this a long-term observing project. As time goes on, the two planets get closer and closer to the horizon by the time the sky darkens. That means having watched their progress for several weeks, even if it’s only once every few days, can make it easier to find them later on.

On May 21, the crescent Moon joins the planets, now lower near the horizon but still easily visible. On the 23rd it will be next to Jupiter and on May 30, Venus will be in line with Castor and Pollux.

So be on the lookout for two bright planets coming together up in the sky.

This month in history:
May 5: Alan Shepard becomes first American in space – 1961
May 9: Hyabusa, first spacecraft to bring back sample from an asteroid, is launched – 2003
May 14: Skylab is launched – 1973
May 18: Hubble Space Telescope serviced for the 23rd (and last)time – 2009
May 25: President Kennedy gives speech challenging nation to land astronaut on Moon before the end of the decade – 1961
May 29: First experimental test of Einstein’s General Theory of Relativity performed during total solar eclipse – 1919

Apr 07

What’s Up in the Sky

What’s Up in the Sky – April, 2015

A Special Lunar Eclipse

What is a tetrad? I did not know either until I started researching this month’s article. You may already be aware of the fact that a total lunar eclipse will occur in the pre-dawn hours of April 4. But you probably are not aware that this will be the third eclipse of the current tetrad. Which brings us back to the question, “what”?

A tetrad is a series of four consecutive total lunar eclipses. Now, you probably are wondering why that is unusual. After all, lunar eclipses generally occur about twice a year, on average. But remember, not all lunar eclipses are total. There are actually three types of lunar eclipses: total, partial, and penumbral.

A penumbral eclipse occurs when the Moon passes through the faint outskirts of Earth’s shadow. An observer on the Moon during such an event would see only part of the Sun covered by the Moon. Thus, penumbral eclipses are often so subtle that they are not even noticed.

A partial eclipse is more pronounced because part, but not all, of the Moon passes through the core of Earth’s shadow so only part of the Moon becomes darkened.

A total eclipse occurs when the entire Moon passes through the darkest part of Earth’s shadow and the entire face of the Moon turns sunset-red for an extended period of time.

Most of the time lunar eclipses occur in random order. We could have a total followed by a penumbral, followed by another total or even partial – the sequence is always unique. But when four eclipses in a row are all total, the sequence is called a tetrad.

This is the second of eight tetrads in the 21st century making it a rather common event. But that has not always been the case. During the three hundred years from 1600 to 1900 there were none.

A unique feature of the current tetrad is that all four eclipses have been and will be visible from North America. The first two occurred in April and October of last year and the fourth one will be on September 27/28 of this year. And even though Saturday’s will begin before dawn and the Moon will set during totality, the one next September will be much easier to witness with totality occurring around midnight.

So now you have a new Scrabble word to use when you are enjoying what’s up in the sky.

This month in history:
April 1: Comet Hale-Bopp nearest Sun – 1997
April 9: NASA selects original seven Mercury astronauts – 1959
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: Apollo 16 lands on the Moon – 1972
April 24: China becomes the fifth nation to launch its own satellite – 1970
April 28: Eugene Shoemaker is born – 1928

Mar 17

What’s Up in the Sky

What’s Up in the Sky – March, 2015

Space “Pioneers”?

I find it interesting that I hear many things for the first time in the locker room at the Dow Center after noon ball. A fellow roundballer asked me if I had heard about the 100 finalists that have been chosen for a one-way trip to Mars. I, of course, actually being on Mars at the time, never had, so he told me all about it. Interestingly, the next day I saw a story in a local news media outlet about the young lady from Dorr who is one of the finalists. So I Googled it.

Turns out, this is not a new idea, but it is the first time people have been recruited to go. I remember being at a NASA Educators’ Conference in conjunction with the (failed) Mars Polar Lander mission in 1999. At that conference I attended a talk by Robert Zubrin of the Mars Society who spoke on the prospect of colonizing Mars with current technologies.

A quick search of the topic reveals that a number of big names, such as Zubrin and Buzz Aldrin, and groups like Mars-One and Mars-to-Stay are already greatly involved in a Mars endeavor. However, the “Mars-One” project is not without its critics. For one thing, it plans to raise significant funds via a reality TV show where viewers will be able to follow the “colonists” 24/7. My first reaction is, right . . . and we cancelled the last two Apollo missions due to lack of interest. When viewers lose interest are we going to leave the explorers stranded? Remember “The Truman Show”? Remember the Space Shuttle?

Of course, the concept has its avid supporters who argue that we are natural explorers and it is our destiny to populate the solar system. Only time will tell the who is right on this, but until there is a driving reason to colonize Mars (other than tourism) I think there is a chance it may end up like gyrocopters and Betamax.

If you are satisfied with observing the planets rather than traveling to them, then next month offers several opportunities. The evening sky is still dominated by Venus in the west and Jupiter in the southeast. In fact, Venus can be your guide to other planets as well. On the evening of March 4, observe Venus with a pair of binoculars around 8:30 p.m. Below it you should be able to spot Mars and between them will be Uranus. If you look one day either side of the 4th, you will be able to pick out Uranus by its change in position.

For an easier event to witness, go out one hour after sunset on March 21 and 22. The thin crescent Moon will be right next to Mars on the 21st and Venus on the 22nd. Hopefully by then the weather will allow us to enjoy what’s up in the sky.

This month in history:
March 1 George O. Abell born – 1927
March 4 Jupiter’s ring is discovered – 1979
March 14 Albert Einstein born – 1879; Gene Cernan born – 1934
March 18 Voskhod 2 cosmonaut, Alexei Leonov, makes worlds first spacewalk – 1965
March 22 Comet Hale-Bopp passes closest to Earth – 1997
March 25 Saturn’s largest moon, Titan, discovered by Christiaan Huygens – 1655

Jan 04

What’s Up in the Sky

What’s Up in the Sky – January, 2015

January Continues the Tradition

By now you have probably heard or read about the connection between various astronomical events and seasonal celebrations. Next month’s sky is a good example of that which the ancients would have found most interesting. We have one planetary close encounter next month with another just beginning. On top of that, the “King of Constellations” begins his seasonal appearance.

The month begins with a pairing of two planets in the west at dusk. The brighter one, Venus, will be easy to find because it is by far the brightest thing in that part of the sky. The other planet, Mercury, will appear as a dim star below Venus. With a clear view of the western horizon, find Venus as soon as it is dark enough and then scan down with binoculars to find Mercury which will appear fifteen times dimmer. Fear not, because if you see anything, it will be Mercury because there is nothing else visible nearby.

The best thing about this event is that it occurs over a period of about three weeks, so there is a good chance for a few clear evenings. In fact, you will want to observe the two planets as many times as possible from January 1 to 21 so you can see them move with respect to each other. They will be closest together on the 10th and 11th and joined by a thin crescent Moon on the 21st.

The crescent Moon will appear spectacularly close to the planet Saturn on the morning of January 16, one hour before sunrise in the southeast. Another Moon-planet encounter occurs when the waning gibbous Moon meets Jupiter on January 7. Look east after ten p.m.

Once you are confident you can identify Venus and Jupiter, continue to pay attention to them as the year progresses. I will be writing about them again in the near future.

Along with all the planetary action, there are some great constellations making their yearly appearances, among them one of the most popular, Orion. Orion has everything – bright stars, cool binocular sights, a great legend, and he just looks cool. With the three belt stars surrounded by four bright stars of his body, he stands out, easily recognized. You can enjoy his beauty with the naked eye while comparing the various colors of the bright stars or spend a good amount of time exploring the belt and sword with a small telescope.

There is much to enjoy this month up in the sky.

This month in history:
Jan. 1: Asteroid Ceres discovered by Giuseppe Piazzi – 1801
Jan. 4: NASA cancels further production of Saturn V rockets – 1970
Jan. 13: First women astronauts selected by NASA – 1978
Jan. 15: Samples of comet dust returned by Stardust spacecraft – 2006
Jan. 27: Apollo 1 astronauts Chaffee, White and Grissom die in fire in capsule-1967
Jan. 28: Seven astronauts killed when Space Shuttle Challenger explodes during launch – 1986

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