Later that day, or night, or...? Well, actually, in interstellar space there is no day or night because for day and night you need to be a planet rotating near a star like the Sun (think about it a little). It’s sort of like one endless night in “outer space,” until we enter a star system like our Solar System. So let’s say just plain later, the Great Galaxy Man poked his head into the control room and said, with as much courage as possible, “Are we there yet, Blasto? Are we alive?” After mulling the latter question over a bit, Blasto replied, “In your case, Sir, the point is debatable, but you can relax. We have whipped around the Galaxy’s central black hole and used its intense gravitational field to propel us toward the halo at over half-a-billion miles per hour. Our time, as measured by those back in the Galactic center, has slowed almost to a stop. But to us, everything appears normal (well almost everything). It’s one of those wierd relativistic effects called time dilation. Anyway, we will be in the halo before you can say Albert Einstein two billion times. Here’s a sketch of our path so far."
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With that Galaxy Man leaped into the control room and shouted, “I knew it! My leadership pulled us through again! Of course you helped too, young Blasto.” Looking somewhat less than pleased, Blasto muttered, “It was nothing oh exhausting one." "What was that Blasto?", said Galaxy Man. "It was nothing my exalted Captain” , replied Blasto. |
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“We are now cruising through a new part of the Galaxy - the DISK - which is my favorite part of the Galaxy because it contains the spiral arms. It’s diameter is about 300,000 light years (remember the 200,000,000,000,000,000,000 school buses put end-to-end?). The disk is amazingly flat. If it were the size of a big 10-inch pancake, it would only be 1/2-inch thick. Unlike the nuclear bulge or the halo, where stars have helter-skelter motions, the stars in the disk go around the Galaxy’s center as if they were nailed to a merry-go-round floor. They do a little jostling around, but mostly they travel in circles, like the picture below shows."
"For a star (like the Sun) that’s about half way between the very center of the Galaxy and the outer edge of the disk, it takes about 250,000,000 years to make one complete lap. You might think that the merry-go-round is spinning rather slowly . But the stars are really like hyper-drive race horses, not turtles. They gallop around the track at over a million miles per hour. The reason it takes 250 million years to go around the track once is that the track is very, very, very long.” In fact the track is about 12 trillion times the distance from the Earth to the Moon. Imagine an unlucky astronaut who had to go to the Moon and back 6,000,000,000,000 times before the mission was finished!" Galaxy Man had his hand up and was waving it furiously, so Blasto stopped his lesson and let the dramatic droid speak.
“The disk of the Galaxy reminds me of a giant frisbee!”, exclaimed Galaxy Man. “Right, as always,” replied a surprised Blasto. “The shape and the spinning of the disk are like a frisbee. But instead of atoms, the galactic frisbee is made up of stars. Let’s take a look at some of these beautiful and mysterious galaxies.”
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“All this information is beginning to spill out of my ears,” complained Galaxy Man. “I’ve been looking through the telescope and I see the most beautiful blue, white and brown marble just floating out there in the disk!
Are those dastardly Red Giants throwing marbles to make us slip and fall? Let’s zing baseball cards back at them!” “Actually, my crazy, no, ah, my courageous Captain,” said Blasto, “that is the planet Earth.” “It is a real gem of a planet and home to 5,000,000,000 people, including most of our readers (though a few seem like they might come from Mars, or perhaps Uranus).” “Blasto!,” cried the G-Man, “watch your language in the presence of an Officer of the Galactic Patrol!” “Sorry Sir! Actually it should be pronounced you-ran-us, not the other way,” explained Blasto. “Well!,” said Galaxy Man stiffly, “please remember that this is a kid’s book; it’s not rated PG-17, or whatever! Anyway, how do they fit 5 billion people on a marble? Must be frightfully crowded!”
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"It might interest you, Sir, to know how nearly empty the disk is. If you shrunk the whole Galaxy so that a typical star was the size of an orange, how close, on average, do you think the closest neighboring orange-sized star would be?" "Why as close as the nearest convenience store, of course," replied Galaxy Man. With admirable diplomacy, Blasto said, "Er,
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ah, right you are Captain, if the next store was 1,000 miles away. Let me reiterate. Hold an orange in your digital unit. Pretend its a disk star. Then even on this highly reduced size scale, the star's nearest neighbor would typically be about 1,000 miles away." Looking a bit perplexed Galaxy Man murmured, "The oranges are 1,000 miles apart? A lot of people must be starving in that galaxy! We must bring them more oranges, and some apples, Blasto!"
“Why do I bother?” Blasto sighed to himself. Realizing the hopelessness of the situation, Blasto said, “Well, Sir, suffice it to say that the stars in the Galaxy are separated by vast stretches of inky black emptiness. Two galaxy disks could pass through each other and the chance of a star from one bumping into a star from the other galaxy is just about zero! It’s sort of like a ghost being able to pass through a wall.”
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“Wow!,” exclaimed Galaxy Man. “That’s empty! I feel so alone! I think I may cry!” Blasto pointed out that Galaxy Man’s head-unit contained no water and that he was not programmed to cry. So the G-Man decided he would just moan a little, if Blasto didn’t mind. Always one to help, Blasto said he wouldn’t mind too much, and that Galaxy Man could throw in a few extra whines too. |
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The dynamic duo sailed through space in near silence for some time until Galaxy Man’s mournful gaze fell upon the the interstellar monitor screen. Suddenly he jumped to his square metal feet and grabbed his ears. “Whoa!,” he cried out. “I see a head ahead! It’s... it’s the head of a knight’s horse, Blasto! Prepare to joust! Get my armor and lance at once, Blasto!”
“Actually, Sir,” said Blasto to the ditsy droid, “while it does resemble a horse’s head, and in fact is called the Horsehead Nebula, it’s really a humongous cloud of gas and dust. As you no doubt remember from our earlier discussions, the Galaxy contains lots of gas and dust clouds, often in really neat shapes like crabs, eagles, butterflies, etc.” “I don’t get it,” replied Galaxy Man, “but I love those pretty pictures you showed me before! And I’m a bit relieved about the joust having been cancelled. I’ve never jousted before, and so I’m way out of practice!”
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Blasto explained that stars are often born in dense interstellar clouds like the Horsehead Nebula. He showed Galaxy Man where a few could be seen emerging from smokestack-like columns. Galaxy Man was a bit dumbstruck, or perhaps I should say starstruck. “So that’s where a star like Michael Jackson comes from? No wonder he’s so good at moon-walking!” Whereupon Blasto started softly banging his space helmet against the wall. “Good, Blasto!,” exclaimed Galaxy Man, “I’ve seen football players get fired up that way.” Then he screamed, “And LOOK! Just in time! AN EXPLOSION! They’re firing at us! Arm the Nukes! Grab some big sticks!” |
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Blasto had a special kind of self-control that comes from putting
up with a troublesome brother or sister. In Blasto’s case,
he put up with 2 litters of ear-chewing droolies before he headed
off for interstellar glory. Blasto spoke slowly and politely as
he explained to his crusading Captain that he had probably seen
a supernova. That’s when a big red-orange star goes
KABLOOOOOOIE! “You see Sir,”
he said calmly, “stars don’t live forever. A typical
star might ‘burn’ 100 million tons of hydrogen
per second. Actually it fuses the atoms, as in the
fusion of 4 hydrogen atoms into one helium atom + energy. At that
rate it would seem like a star would burn up its fuel very
quickly, but N-O-O-O! A typical star has so much hydrogen to fuse
that it can keep on using up
“Anyway, when an especially heavy star finally begins to run out of fuel, it cools and then starts to collapse. The collapse ends in an awesome explosion - releasing as much energy released as in 100,000,000,000,000,000,000,000,000,000,000 atomic bombs. Yup, that’s 1032 atomic bombs! So Sir, you are quite right that it’s an explosion, but it’s not a bomb shot at us.” “Blasto, let’s cut out the astro-babble,” said Galaxy Man sternly. “It is not relevant to our mission! I know an explosion when I see one, Blasto!” After a long silence, Galaxy Man’s eyes began to to glow a deep red color. “L-L-Look B-B-Blasto,” he said slowly, his speakers quivering, “R-R-Red G-G-Giants!”
his eyes, Blasto said, “In a nutshell,
my optic Captain, the Earth is quite a sizeable planet. There is plenty
of room for 
ssure. Before Galaxy Man could think too
much more about this unfortunate incident, Blasto quickly changed subjects.