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Einstein's Lenses: The Trip to Mars Begins



Part Four - The Trip to Mars Begins


When Rigby and Casey first boarded the shuttle back on Diem Dues 3, Rigby couldn't help but think back to the old days. The shuttles for interplanetary travel were much different when Rigby took her first off-Earth assignment. Things were scarier back then because so much was unknown. People would bring along personal space suits and oxygen. One had to wear magnetic shoes to keep themselves on the floor, and launch time was a bumpy ride. The shuttle living space had been primarily limited to the initial launch seating area, which resembled something like the interior of a standard military aircraft on Earth: a lot of exposed metal, bolts uncovered, practical well-restrained seats, and nothing for entertainment. And while the initial launch area remained a cold, metallic, and functional setting, the launch itself was now smooth, and the conversations with strangers were easy. The loud, piercing sounds of thruster engines echoing through the launch chambers were long gone. Today, the passengers were restricted to this area only during the first and last 30 minutes of the trip. Depending on your personality, you could make friends or wait it out.

The living areas of the ship now usually included a kitchen, dining room, several small sitting rooms, and then, of course, the sleeping cabins. Passengers on the shuttle were likely to be on different sleep schedules, depending on their job or tastes. There was no consistent routine. This far out–pretty much anywhere beyond Mars–people’s schedules rarely aligned. And it worked out pretty well to share the cabins half and half. One set of people inhabited any given cabin for 12 hours, and they would alternate every 12 hours with a different group of passengers. Of course, if you were wealthy, you might just buy it out for the entire time for privacy and ease of use. But since this was a work trip, Rigby tried to keep the expenses minimal.

Still waiting in the launch cabin with Casey, Rigby wondered about the telescope they would be visiting. She then realized she didn’t understand how they worked. The detective turned to Casey, “Casey, how do telescopes work? I know that it’s a combination of mirrors and lenses, but I guess I didn’t consider it beyond that.”

“They are actually quite varied. As you can imagine, lenses and mirrors can be arranged to achieve different ends in more than one way. They will vary based on magnification, of course, but also resolution and are tailored to different wavelengths of light. For example, in the classic movie “Contact,” the radio telescope at Arecibo Observatory is huge. It’s a 1000 ft spherical reflector dish built back in the 1960s.”

“Oh yes! I have seen that movie. Crazy old. I can’t imagine what it would have been like to live back in the 1900s. Their world was so small,” said Rigby.

“Simpler times, that’s for sure,” replied Casey. She continued, “The telescope I had growing up, however, was about 2-3 ft long, stationed on a tripod, and the framework consisted of just a couple of mirrors and a lens. And the list goes on, Galileo used a telescope with only two lenses to discover four moons of Jupiter in the early 1600's, but even among two lens telescopes there is some variety. To give you an idea of how telescopes work, I'll step you through the simplest two lens telescope I can think of. Most basically, you need to separate two specific types of lenses by a special distance. Each lens would have to look roughly like this where they bulge out a bit.” Casey scribbled a drawing of what she meant by the lens's shape.

“The special distance you would need to separate two lenses by is the sum of the focal lengths of the lenses,” said Casey.

“And how do you find out what the focal length of a lens is?” asked Rigby.

“Good question. The focal length is where incoming light from a distant object all comes together to focus on the other side of the lens. Like this,” said Casey as she scribbled on a piece of paper.

“If you stood with a lens near a window, for example, you could take a piece of paper, and if you were to put it at exactly the right spot, distant objects through the window would be shown crisply on the paper–albeit much smaller and upside down. The exact right spot gives you roughly the focal length of the lens. It’s neat to see, and you should try it if you haven’t seen it. And, a telescope can be made with just two lenses separated by the sum of their focal lengths,” Casey said as she continued to draw.

“One lens puts the image of a distant object at its focal point, which is then designed to be at a place that is one focal length away from the other lens, and then you see it after that. There are some subtleties I'm glossing over, but it gives you the basic idea,” said Casey.

“And, you’ll notice I drew the lens you look through as the ‘smaller’ one. I did that because if you want the image to be larger when you look through the two lenses, you have to look through the one with a smaller focal length. The magnification is determined by the ‘bigger’ lens in the picture’s focal length divided by the ‘smaller’ lens’s focal length. So if the focal length of the bigger one is twice that of the small one, any image you saw through the telescope would be twice as big compared to what you would see with your naked eye. But, we don’t have to go into more detail until you want to build one,” said Casey with a smile*.

“So basically, to make a telescope, you redirect light that you have collected in clever ways that make the image look bigger?” said Rigby. Casey nodded in affirmation. Then Rigby continued, “I have also heard about gravitational lensing with galaxies and how multiple images of the galaxies can be created or how their images can be smeared out into arcs and things like that. Like this," Rigby brought up an image on a portable screen to show Casey.

Hubble image of LRG 3-757; this is the distorted image of a galaxy into a ring shape due to gravitational lensing.

"How does that work?” Rigby asked.

“Well, gravity does act a lot like the standard lenses we have been discussing. Gravity bends light, and there is a lot you can do with turning light in specific ways, as we just discussed. Take the bottom of a wine glass and hold it up. You will see how the image on the other side smears out in a circle on the bottom rim, and that can also similarly happen to the light moving through a gravitational field coming from a galaxy on its way to us. Gravity can cause the light of a galaxy to smear out in a ring like shape on its way to our Solar system, which is of course where we see it."

Casey smiled. She rather liked to dive into physics with Rigby. She had a raw child-like curiosity about her that physicists quite enjoy.

Rigby noticed a new ring on Casey's finger as the initial launch sequence was winding down.

"That's an exquisite ring," said Rigby as she pointed to Casey's hand. "Is it new?"

The ring had a thick gold band and a colorful stone inlay. Casey looked at the ring. She was pretty pleased with how it had turned out.

"Yes. It is. I'm glad you like it," said Casey. It was a pleasant sort of ring, even though it had been created for a much deeper purpose than aesthetic appreciation. Casey looked at Rigby and smiled. Rigby wondered about the story behind it, but soon she began to self-indulge and admire her own rings.

Casey started wondering if Rigby would ask about the ring further when a sense of dread fell over her. She hadn't considered how Rigby would take it until this point. What if Rigby confiscated it? Or worse, if she thought it was so bad, she charged her with some kind of violation of the Solar Standard? The bell rang to indicate that passengers could leave the launch cabin.

Casey got up suddenly, “I need to go to the bathroom. I’ll catch you later in the dining room?”

“Sure,” said Rigby.

Casey walked straight down the hall and took a left. The door color was green, which indicated that the restroom was free. The door opened a few moments after as she stood looking into the sensor above the opening. Once she was inside, she felt like she could think. Like she could breathe.

“One of these days...” said Casey, but then she paused. She thought that what she had done this time would swallow her whole. Why did she always have to do something like this? Again and again and again. “But why does it matter what I do? Why do people care?” she thought to herself.

“If Rigby is a friend,” Casey thought, “but we’re not friends… are we? Even if she considered me as a colleague really. And,” she sighed audibly, “it’s so much more difficult if we have to do it the Solar Standard way. By the Solar Standard.” Casey mouthed those last words as she looked at herself in the mirror. “What was that anyway? Who came up with it? It’s not like it was my idea.” She then noticed the smell of cleaning products. It was some mix of pine and bleach. She knew that Rigby wouldn’t be thrilled, and she knew that the hammer of disapproval was inevitable. She stared up at the ceiling in the single-stall restroom, and she wondered how long would be an appropriate amount of time before she had to go back out and pretend that everything was “normal.”

The bathroom was relatively unremarkable: a small mirror, worn countertops. The design was an efficient use of space, decorated in shades of gray, but there was something calming to it.

Casey just didn’t feel like she could live with it. It was unbearable. But what could she do now? It’s not like she could go back in time. “It’s never like you can go back in time…” she thought. She had taken it with her; she had brought it along, and that is that. Que Será, Será, or so they say, but she couldn’t help feeling just a little bit nauseous. “She will be so smug. Rigby is just perfect all the time,” Casey imagined.

She wanted to kick herself for doing something that once again would haunt her in this way, आसमान से गिरा, खजूर में अटका. Until one of two things happened this torment would continue. Either Rigby figured it out, or the trip was over. Yet, as Casey thought about it more, there was another way out. She could just tell her. Explain why she brought it. Explain how crucial it is for determining whether or not people were telling the truth about where they had been. Casey said to herself that it was, after all, only a portable DNA and fingerprint collector, well, sort of. Yes, it was an invasion of privacy, and yes, she could kind of see-through walls, but it’s not like she would use it casually; I mean, it had been outlawed in certain parts of the solar system for good-ish various reasons, but it’s also not like Rigby couldn’t get ahold of one if she wanted one. But perhaps not always in time, which is the point!

Casey pulled the ring off her finger and put it on the bathroom counter. It was a well-equipped data collection service unit with many of the latest features, often referred to as ‘bugs.’ But it did so much more than just gather information. It collected samples and took pictures, yes, but then you could use it to artfully reconstruct all sorts of things. When Rigby’s unit was using something to wrap up the impression details of the crime scene, they used similar devices; this device was effectively a portable version of that. However, ‘bugs’ are more insidious in how hidden they are, and Casey’s ring was not quite as detailed or powerful without all of the added benefits of what a crime unit can provide. Depending on how much money you intended to invest, the form of the ‘bug’ could be a flying insect or the marginally less expensive versions could be worn around the finger in the form of a ring, like Casey’s.

They weren’t outlawed everywhere. But certainly, on Mars their use was limited and on Earth possession carried a hefty fine. Generally, their use was frowned upon in places with a strong sense of communal identity, in areas that included strict policing, or in highly controlled terraformation projects. Back around the vicinity of Saturn, it’s sort of a grey area. Casey was confident now that Rigby would be furious. They were pretty hard to come by. And, for the level of functionality of the one Casey had, it was kind of a wonder how she could afford one. The cost might raise certain questions in Rigby’s eye, but Casey was thankful that Rigby wasn’t usually prone to prying into Casey’s personal life.

The ring did go a bit beyond the corporeal, too, in a way. It could tell you the basic emotional state of a person. Perhaps she should use it on Rigby to find the best time to break it to her? “No, I don’t care what she thinks. I was right. I’m certainly taking it with me. I’m going to use it as I please,” Casey mused. “And there is just nothing that Rigby will say to deter me because getting impressions on the spot will be incredibly useful. We don’t have perfect memories, and we can’t trust people in general either, so that’s that.” Casey was feeling much better about herself. She had forgotten about her surroundings for a moment. But, Casey now had a confidence that allowed her to place the ring back on her finger and re-enter the usual distractions of everyday life. She opened the bathroom door, walked out, and turned towards the dining hall.

Casey skirted around the corner staring at the floor as she walked until she almost bumped into someone and began paying more attention. She forgot for a moment where the dining room was. But, luckily, there was a screen nearby. She tapped it and took a look at the map of the shuttle. She took note of where their sleeping cabin was and continued on her way to the dining room. She saw Rigby sitting at a table in the back corner of the dining hall.

It was a rather beautiful space. And, on smaller shuttles like these, the dining rooms were usually the most well-decorated areas of the ship. There were windows to look out into the blackness of space, and the lighting on the walls was soft but not dim. Casey sat down at the little round table with Rigby, crossed her legs, and leaned back. Rigby had placed a small dish of fruit and nuts to share on the table.

“They seemed to have a wide variety of choices. Please feel free to have some of the walnuts, dried figs, and dates I picked up. They were the simplest thing that I knew I would like,” said Rigby.

Casey said, “Oh, sure, I might try a few pastries too. But you are correct. Sometimes it’s better to play it safe; these ships don’t always have the best food to offer.”

Rigby then grabbed some walnuts and a dried fig and said, “However, we will probably get something more exciting at Garden Station. There’s bound to be some interesting things that we pick up there.”

Casey cheerily replied, “Ah yes. I will try not to be too disappointed because I bet you’re right. And, it will be a taste of the future as well. I can’t wait until we get regular shipments from Garden Station on Diem Deus.”

“Won’t that be nice?” said Rigby.


The following book was used as a reference for this post, Optics by Eugene Hecht. It is an excellent undergraduate level resource to learn more about the basics of how telescopes work and more.

Hubble Image:

This blog post will also available as a podcast in the near future, as read by the author, Erin Blauvelt.

Author: Erin Blauvelt, PhD


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