USM Southworth Planetarium

From the USM Southworth Planetarium
“While out on a pleasant ocean jaunt, a lady in a kayak became so chilly she decided to light a small warming fire. The kayak caught the flame and sank, thereby proving that you can’t have your kayak and heat it, too.”

THE DAILY ASTRONOMER
July 21, 2011
Pluto’s Fourth Moon

Astronomers using the Hubble Space Telescope have just discovered a fourth moon around Pluto, a world that some still consider a planet despite the International Astronomical Union’s ill-advised decision to demote it from its previous planet status. When Clyde Tombaugh discovered Pluto in 1930, Pluto was believed to have been without companion: an icy sphere orbiting solo along the solar system’s nether edge. In 1978, US Naval Observatory astronomer James Christy found what was then believed to be Pluto’s only moon, Charon. Classified as the largest moon when measured in proportion to its parent body, Charon is 12% as massive as Pluto. (Our moon is only 1.3% as massive as Earth.) Charon and Pluto are unusual in that they have established mutual synchronous rotation: meaning that their orbital periods around their system’s barycenter (gravity center) is equal to their respective rotation periods. Such gravitational equilibrium is only truly achievable when the bodies are of comparable sizes and masses. Consequently, many astronomers believed that Pluto-Charon should be classified as a double planet.

In 2005, the Hubble Space Telescope captured images of two much smaller satellites, named Nix and Hydra. Whereas Charon’s diameter is about 650 miles, Nix and Hydra are each less than 75 miles across. Compared to Pluto and Charon, Nix and Hydra are minuscule: little left over worlds created with Pluto and Charon. While the provenance of these worlds remains uncertain, some theorize that a powerful collision, perhaps the one responsible for Uranus’ steep tilt, destroyed parts of an outer world. The ejected debris eventually gathered together to form Pluto and its attendant moons.

Now, we know that Pluto has four moons. The latest one discovered, named P4, is dwarfed even by Nix and Hydra. With an estimated diameter between 10 – 21 miles, P4 is truly a small piece of matter revolving around Pluto. Its discovery was just the latest accomplishment in the now legendary history of the once maligned Hubble Space Telescope.* The ability to detect such a tiny world from a three billion mile distance attests to the Hubble Space Telescope’s continued viability.

And, we now acknowledge the latest find in our solar system: one that apparently teems with worlds, some of which remain unknown.

*Soon after its launch, the Hubble Space Telescope was found to have defective optics. Specifically, its main mirror was ground one micron (one millionth of a meter) too fine. While this error might seem minor, it is highly significant in optical equipment as sophisticated as those within the HST. As a result of this mistake, the Hubble Space Telescope could not bring any images into sharp focus. Ridiculed as NASA’s most expensive failure, the HST’s optics were repaired and its reputation immediately restored.

From the USM Southworth Planetarium
“Atoms and evenings”

THE DAILY ASTRONOMER
July 19, 2011
Christmas in July

Tense wait in restless line to glum face sentry with boundary-challenged wand. Shaky flight through turbulent winds beside 120 pounds of snorting child flesh. Toxic orange pop splash on new blouse. “Oh, I’m sorry about that. Frankie, be careful. What do you say?” Snorted insoucient apologies during suicide descent. Hates this part. Pilot in pit finally had it? No. Safe landing. Compressed humanity fidgeting in humid tube. The seconds sprout anchors. Incoherent thanks over static. Doors open; oxygen again. Trudges toward tunnel; passes cleft chin and practiced grin nodding to mortals. Turn. Twist. Turn again. Terminal buzz. Doesn’t care. Wants what’s left of luggage. Ah, the conveyor belt ho! and over strange shoulders a grinning son-in-law. Dreaded, but expected. Thirty-two years of a perfect marriage makes one capable of smiling at dismay. “Ah, you’re here, ma-by-gaw!” Yes, Ted, you genius. Nanosecond embrace. “Where’s Helen?” Under sedation? “Couldn’t come. She’s picking up Jenny’s friend for a sleep over. Full and fun house tonight, isn’t it?!” Spiffing. Traversed half a continient to become a 62 year-old zoo exhibit for teenage girls. Yes, you’ll be me someday if you skip meals and don’t pray.

Luggage emerges. “Oh, let me get that. You must be exhausted after your flight!” Yes, they had me get out and turn the crank twice. Trailing knight to parking garage. Hazy jet streams coarsing through pillars. Concrete footfalls echo. “Lovely car.” Key chain click. Car lights flash. How does that work, again? Beep. Unlock. Trunk pop. Hoist in case. Slam. Bam. On the Road. Situation demands politeness, so I’ll sleep. Closes eyes and rests against window. Son-not-by-choice shouts something. “I’m expecting some visitors later, myself.” Huh? Didn’t quite catch… Darkness returns. Mile markers pass. Ted whistles. Shows off air conditioning system by rolling down all the windows. Glass support suddenly gone; my head’s outside… I’m awake!

“Is that too much air, Maw?!”

Driveway ahead. Deceleration. Blinker. Head still attached.
Stop. Unbuckle. “Ah, Helen’s home. She’ll take care of you. I have some things to do in the garage.”
Walking. Door open. “Mom! You’re here in one piece.” “Yes, Helen.” Hug. Mind the head…
“Oh, you look exhausted. Why not go into the guest room for a nice lie down?”
Great tone of voice. Is that before or after the bib fitting?
“Maybe later. Where’s Jenny?”
“In with her friend playing Farmville on Facebook. She’s been anxious to explain it to you.”

Thirty seconds later.
Lying down in Guest Room.
“I’ll call when dinner’s ready, Mom.”
Yes, do that.
Strange bed. Firm surface, tight coils. This is for guests? Ted’s probably lost both friends by now.
Breeze is soft and warm. Air redolent of hyacinth. Distant mower.
More tired than I thought.
Barking dog three light years away somewhere out in another part of July.
Funny how you don’t realize how tired you are until you actually lie..

Hears a door opening gently. What time is it? Seems much later. Sky looks bronze through eye slits.
“Shh…she’ll eat when she wakes up. Let her sleep.”

Evening air exhalations. Everything peaceful. Oberon and Puck playing hopscotch outside.
Mr Darcy is grilling down the street. Maybe I’ll just stay here forev…

Bam! Bam!
The foundation cracks and shatters as a yak bangs his head against a bridge abutment and screams “It works! It works! It works!”
What do you know, I’m awake. Almost dark now.
Mad killer tears door off hinges.
Good…

“Maw, it works! It works!!!”
Damn, it’s Ted.
“Wake up! Wake up! Come out into the living room!!”
Sounds of his retreating footfalls down the corridor.
Car doors close just outside.
One hundred twenty decibels of undiluted son-law resounds throughout the house. “It works! It works!”

I guess I’m getting up.

Front door opens and slams. “Ted, what’s going on?! We could hear you screaming outside. The girls are scared to…oh, my God what on Earth have you done to the living room?!”
Ted’s maniacal laughter follows.

Oh, let’s go see the living room.

Helen in profile by the door. Mesmerized, wide-eyed and quivering. My daughter..speechless and terrified. Serves her right.

Approaching now. Ted laughing. Helen looks faint-headed. Girls nowhere in sight.
Passing family photos on the wall and three more steps until I view the

Large black scorch mark on the wall, like a mammoth freshly-swatted spider.
Let’s see..what else…
Arrayed around it a tangle of multi-colored lights, most dangling, all blinking. On the carpet, strewn with snow (!), a tidy stack of exquisitely wrapped presents arranged in a circle. Across the floor, filaments of wrapping paper, as though spit out of a shredder.
Set on the paper, a tray with steaming cups of hot liquid. Next to them, a tiny snowman looking, well, confused.
Amongst all this, Ted, in a sweat stained santa hat and lab coat nearly dancing with glee.

The front door opens again. Jenny and a timid-looking black haired girl enter.
“Mom, is everything……”

So, now we’re all standing dumbfounded before the sight of Ted dancing in a disaster area. This is sort of the vacation I expected, actually.

Helen, almost in tears, speaks first. “What have you done?”

Ted beamed. “It’ll take me a moment to explain.”

“I have time.” Helen sounds breathless.

“Einstein-Rosen Bridge, honey. Well, that’s the proper term. Really, it’s a singularity, a mathematical point of no dimension that I manged to fashion in the garage precisely on Christmas morning last year. I only said I was going out to varnish wood, but that was really something of a deception. I’m not that good with woodworking…” He spots his daughter’s friend and extends his blackened hand. “Oh, how rude am I? Hello, little one. I’m Jenny’s Dad. I was in the garage when Jenny’s mom took you two out to get ice cream. Great to meet you.”

How touching. Girl is trying to push herself through the wall pores as the hand approaches.

Ted backs away. “I get it. Shy…Me, too.”

“Dad, are you ok?”

“Never better, sweetheart! Merry Christmas!! What do you think?”

“I..”

“As I was just about to explain to your mother, I crafted a singularity, like a black hole, but somewhat different, in the garage on Christmas morning. I didn’t tell anyone what I was doing, because that would have ruined the surprise. Oh, boy, I’ll bet I’m the only guy on the block to actually cook up a real singularity.”

Family pride.

“Not that tough really, as it turns out, rulers are stuffed to the gills with singularities. Infinite number, actually, although infinity’s not a number, but a set. The problem is, what do you do with a singularity once you fashion one, because, let’s face it, the trick is not in the development but the application. That’s the real problem about being a pioneer. You have to figure out the usage, too. So, what did I decide to do?”

This moment of dramatic suspense is hanging limply like poorly hung Christmas lights.

“I sent Christmas to July! A wormhole connected the singularity through space-time and through it I sent Christmas. Or, at least selected pieces of it. You know, when all of you were in the den watching Ralphie’s Dad pulling that leg lamp out of the box? I snuck out here and tossed a few lights and presents through the Einstein-Rosen bridge, or the wormhole, and made sure they’d arrive in the summer. And to test the thermodynamical properties of my wormhole, I included a few cups of hot chocolate and snow. You’ll notice that the hot chocolate is still hot and the snow’s still frozen. It is like they appeared in an instant, which, of course, they did. My visitors have arrived!”

“Mom, should I call an ambulance?”

Count on Jenny to interrupt during the good parts.

“No, no, no!” Ted’s shouting, making us all much more at ease. “Sit! Sit! Sit! We have to celebrate Christmas. It traveled through a time vortex and we might as well enjoy it!”

Well, perfect time to humor the manic. I’ll sit in the car.

“Madge, there’s your favorite barcalounger. Girls, on the couch. Honey, over here, next to me. I want you to share in my triumph.”

Payback for taking that biker to the prom.

Well, this scene is Norman Rockwell. Two girls clinging to each other on the couch; shell shocked Helen poised on the most distorted homemade chair this side of an Escher painting and Ted who nearly slipped on carpet snow as he reached down for a present.

I wonder if I’ll get the serpent cadaver, valet’s kidneys or the black candles. Watching now as Jenny opens her big box, looking like a pint-sized explosives ordinance disposal expert. She opens, winces, and sees

“An Apple i-phone and X-Box Kinect!”

She’s smiling?

“And, for your little friend.”

Furious unwrapping. Room tension oddly easing…

“An X-Box 360!!”

“I hope it works, what will all the tidal forces associated with wormholes one can never be sure how much damage Christmas presents will sustain. You’ll notice what the differential gravity did to one of the wrapped presents.” He is now gesturing to the wrapping paper pieces strewn about the floor.

“Why don’t you two run along now and try those out?”

Jenny runs and hugs her father. “Thanks, Dad. You’re great!”

They happily flee away. Watching Ted pass Helen a present. Still anxious, she trembles slightly while opening it. She opens the wrapping and stares at the contents.
“Cashmere sweater and diamond necklace.”

“I wasn’t as worried about the diamonds, as they’re so hard and able to withstand the tidal forces. Although, a real black hole would have made short work even of crystallized carbon.”

“I don’t know what to say.”

“Madge, I believe this is for you.”

Wow. I can’t wait to find out what the…

Norelco Razor and Sports Illustrated Swimsuit Issues years 1998 – 2010. Windfall.

“Yeah, well, that was the present I bought for Langley, but seeing as he’s coming later this week, you can have it.”

I’d dance if I didn’t have rickets.

Snow melting into water. Ted, still gleeful, hands us all hot chocolate. Perfect complement for the evening heat.
Ted takes his cup and sips it slowly. Helen, often rubbing the sweater against her cheek and displaying the necklace, has learned patience.

“I was actually aiming the Christmas fragments for July 25, so they’d materialize exactly five months after the holiday…”

Math skills…

“July 19th is close. After all, this is my first attempt. Now that I know it is possible, think of the possibilities. One thing I have always hated it the let down when the holidays end. Now, I can transport holiday fragments to other times, like time meteoroids. Thanksgiving cranberry sauce pops out in February; Independence Day fire works emerge in October. Green Beer shows up out of nowhere on New Year’s Eve; perhaps a little easter egg arrives in April…”

Doesn’t Easter generally happen in April, anyw…

“Into the future and, if I have my calculus right, into the past. Although, I haven’t had any formal education in astrophysics…”

Really?

“..the prospects of filling the year with holiday pieces are infinite, well, almost, because infinity isn’t really a…”

“Dad!”

There’s Jenny interrupting again.

“What’s wrong, sweetheart?”

“There are three Jack O’Lanterns in the bathroom!

“Three?”

“They made me jump when I saw them.”

“Are they all intact?”

“Yes.”

Ted’s smiles again and looks at us. “Well, I’m eventually going to get better at this.”

From the USM Southworth Planetarium
“Honk if you hate highway noise.”

THE DAILY ASTRONOMER
July 18, 2011
Weighing the Stars

*******************************************
Don’t fret!
That’s our motto: if you just joined, not every
DA will be quite as math-happy as this one.
They do vary….somewhat.
********************************************
Well, here’s one for the fatalists: a star’s life is, indeed, pre-determined. The determinative factor is its mass, or, weight.* This one stellar feature determines the star’s energy output, life span, and even the elements it will fuse in its core. (Stars generate energy by fusing light elements into heavier elements. Carbon is the “heaviest” element our Sun will create, wherease more massive stars produce such extreme core temperatures they can create oxygen, silicon and even iron.) If you want to know a star and how it will live, you need to know its mass.

That’s all very well, but the issue brings up a tricky matter: how can we possibly know a star’s mass? As we’ve never traveled to the stars with our scales, it seems curious that we could determine how massive any of them are. Yet we do know their masses and, by extension, their life cycles, because of that miracle of remote sensing called astrophysics.

We’ll start with the fundamental idea and then delve into specifics. This idea, called the “Fundamental Theorem of Astrophysics” asserts that all physical laws we’ve developed here on Earth apply equally well to other places in the Universe. That such laws are, well, universal is quite convenient, for we can determine a celestial object’s physical characteristics by observing its light and motions and then performing calculations based on home-grown physics.

A perfect example involves ascertaining stellar masses. Such determinations are only possible because many stars exist in systems of two (binary) or more. To explain how we can use a binary star system to ascertain the masses of both components, we’ll envision two components of a simple binary star. Over a long time period, an astronomer will observe these stars and notice how the positions of each star changes relative to each other. Such changes occur because the stars revolve around a barycenter (or a common center of gravity). If the clever astronomer knows the binary star’s distance from the solar system**, she’ll then be able to measure both the distance between these stars and the time period required for them to complete one orbit. As Johannes Kepler (1571-1630) realized, the orbital period of two bodies relates directly to their separation distance. This relationship is the essence of Kepler’s Third Law***.

Isaac Newton (1642 -1727) later determined that the masses of two gravitationally bound bodies determine their orbital periods and separation distances. So, if the clever astronomer knows the distances of both stars from their gravity center and also their orbital time periods, she can know the combined masses of both stars. This value alone won’t yield the individual masses unless the astronomer knows each star’s distance from the barycenter. For instance, if star A is five times farther away from the barycenter than star B, the astronomer will know that star B is five times more massive than star A.**** If the two stars together are thirty times more massive than the Sun, we can deduce that star B is 25 times more massive than the Sun and Star S is 5 times more massive.

We know the Sun’s mass by applying Kepler’s law to the Sun and one of its planets, such as, well, Earth. We know Earth’s orbital period and mean distance. As was the case with the binary star, the masses of the Sun and Earth determined these values. Since we know the period and distance, we then know the combined masses of the Sun and Earth. Since the Sun is about 330,000 times more massive than our puny planet, we assume that this combined mass is about equal to the Sun’s mass. (Yes, in stellar terms, we’re living out our lives on a negligble sphere.)

So, we combine observations with our physics knowledge to know the masses of the stars within a binary. By compiling data from hundreds of binaries, astronomers can know the masses of all types of stars from the hot O-stars to the cooler M-stars and all those in between. We can then determine how the mass of a star affects its temperature, luminosity and its other properties.

Astrophysics is, at its base, a beautiful daisy chain of seeing and knowing.

*That banshee wailing you just enjoyed was the sound issuing from every physicist-subscriber giving vent to his/her demons. You understand that in the physics world, arson for profit is faintly discouraged, but using the words “mass” and “weight” as synonyms is a detestable practise Vlad the Impaler would have disavowed. Mass and weight are not the same. Mass measures an object’s resistance to motion change, or inertia. Weight is a measure of an object’s mass multiplied by the surface gravity of the body on which it is located (planet or moon.) So, your mass won’t change if you’re on Earth or the Moon, but since the latter’s surface gravity is much weaker (1/6th the magnitude’s of Earth) your Earth weight will be six times greater than your Moon weight.

**Astronomers have reliable stellar distance determination methods such as parallax shift. Just so we can stay on track, we’ll assume that we know this distance without explaining how we gained this knowledge. We’ll leave that adventure for another day.

***Kepler’s Third Law (called the “Harmonic Law”) states that the cube of a planet’s average distance from the Sun (mathematically called the “semi-major axis”) is proportional to the square of the planet’s orbital period. (The cube of A is A x A x A; the square of P is just P x P.)

****If you want to try this trick at home (and check our calculations), the mass of star A multiplied by its distance from the barycenter is equal to the mass of star B and its barycentric distance We write this as M(a) x D(a) = M(b) x D(b).

From the USM Southworth Planetarium
“Good morning, Milky Way!”

THE DAILY ASTRONOMER
July 15, 2011
Quiz: 1846

Earlier this week, we posted a two-part DA pertaining to Neptune. On Tuesday, July 12, Neptune completed its first orbit since it discovery in 1846. So, we decided that instead of merely re-posting a quiz (which we’ve done for the last 24 weeks), to craft a new quiz about the year 1846! Nobody alive today was actually alive then, so you won’t have a power line option. While this quiz is perhaps more historical than astronomical, it will at least give us an appreciation for how much time has elapsed during only one Neptunian orbit!

1. Ok, first things first: who was the President of the United States in 1846?
a. Ronald Reagan
b. Zachary Taylor
c. Millard Fillmore
d. James Polk

2. Which historical event, surprisingly, actually happened in 1846?
a. the final draft of the Constitution was finally ratified
b. the liberty bell was cracked
c. the first southern state seceded from the union
d. the Great Chicago Fire (the first one)

3. In May 1846, Adolphe Sax obtained a patent for the ________________, a musical instrument that he invented.
a. Saxophone, of course
b. Banjo
c. xylophone
d. player piano

4. What war started in 1846?
a. The War of 1846
b. The Mexican-American War
c. The Aroostook War
d. The Cypriot War

5. Which state was admitted to the Union on the last week of 1846?
a. Iowa
b. Nebraska
c. Colorado
d. Louisiana

6. The world’s human population reached 2 billion…
a. before 1846
b. in 1846
c. within the decade following 1846
d. more than fifty years after 1846

7. What other invention was patented in 1846?
a. chewing gum
b. sewing machine
c. Gatling gun (precursor to the machine gun)
d. panty hose

ANSWERS

1. d. James Polk (1845-1849)

2. b. the liberty bell was cracked
It cracked on February 26th when somebody rang it too vigorously during a celebration of George Washington’s birthday.

3. a. Saxophone

4. b. The Mexican-American War

5 a. Iowa

6. d. more than fifty years after 1846
The world population was believed to be two billion in 1927.

7. b. sewing machine

From the USM Southworth Planetarium
“Da da da da da…da da da da…..heavens, that really loses something when there’s no music.”

THE DAILY ASTRONOMER
July 14, 2011
The Summer Ring

Think of it as a light circle: a faint smoke ring as though from a hobbit pipe that only when viewed over the course of centuries will exhibit only the most gradual dissipation. We call it the Ring Nebula, a planetary nebula in the summer constellation Lyra the Harp. Despite its name, a planetary nebula has no association with planets. Eighteenth century astronomer William Herschel coined the term since the disc-like nebulae resemble planets when telescopically observed. However, they are stellar objects: gaseous shells cast off my giant stars toward the end of their lives.

At a distance of approximately 4,000 light years, the Ring Nebula is not the closest planetary nebula, but is one of the most famous. With a diameter 500 times greater than that of our solar system, it encompasses an angular diameter of 1.2 arc-minutes and is therefore an easy small telescope object, hence its fame. [See an image of the Ring Nebula on the remains of our web-site: www.usm.maine.edu/planet The Ring Nebula is the 7th slide on the home page's slide show.]

Apart from being a pleasing sight, the Ring Nebula shows us the Sun’s future. Billions of years from now, the Sun will expand into the red giant stage. At this point, its outer layers will extend well into the inner solar system, (even beyond Earth.) When its core fusion reactions cease, it will expel these layers into space, exposing a super-hot white dwarf star at its center. Within the Ring Nebula’s center we see a 16th magnitude* white dwarf.

White dwarfs are not stars, but stellar remnants. Unlike stars, they do not generate energy, but instead slowly wick it away. Also, unlike stars, their structure is not sustained by energy pressure, but instead by electron degeneracy. Electrons within the white dwarf resist the gravitational contraction as they can only be so close to each other. Provided the white dwarf is less than 1.4 times as massive as the Sun, electron degeneracy pressure is a sufficient resistance force to prevent it from collapsing.
Despite their names, they are not always white. As they cool over millions of years, their color changes.

The Ring Nebula is a celebrated sight for astronomers surveying the Summer Sky. See it tonight through your telescope with the diamond-shaped constellation Lyra.

*16th magnitude refers to the object’s apparent brightness. Astronomers use the magnitude scale to measure a celestial object’s brightness. The faintest objects visible to the unaided eye have a magnitude of about 6. A 16th magnitude white dwarf is about 10,000 times fainter than a magnitude 6 object. That’s rather faint.