He pushed the button and started up the computer in his study. Yesterday, he’d picked out three yellow dwarfs and emailed Thomas the coordinates. Two of them were on the spherical shell, and one was not. Of course, it would be better to measure 20 stars, but he had to take what he could get.
He grabbed a package of cookies from the kitchen. His tension was rising. He knew his login and password for the Max Planck Institute’s computer system by heart, even though it consisted of four groups of three random characters each. He powered up the terminal and entered the address. An input field appeared, and he entered the login that Thomas had given him, then opened a chat session.
It was five minutes to one.
“Hello, Peter.”
“Hi, Thomas. Glad to hear it’s working out.”
“Let’s hope for the best. You just have to sit back.”
“I can do that.”
“Then let’s begin our journey into the depths of space.”
As if by magic, letters appeared on his screen. Peter adjusted the window to the full screen size. Now he would see everything that Thomas saw.
A program window opened which read, ‘MPIfR Effelsberg 100m Telescope Control.’ Four buttons were visible at the top. The first one was red and labeled ‘Stop.’ The other three were green and labeled ‘Continue,’ ‘Repeat,’ and ‘Start.’ To the left was a long list. None of their entries meant anything to him. If he didn’t have Thomas’s help, he would have been lost before he’d even started.
The mouse pointer moved to ‘Pointing.’
“I point the antenna at a bright source to test,” Thomas explained.
It opened a second window in which a data chart appeared.
“Works.”
The mouse pointer changed to ‘Focus.’ Again, data came in. Then it went back to ‘Pointing.’
“It looks good,” Thomas said. “I just measured the H65-alpha transition from hydrogen at 23.4 gigahertz. The system is dazzling.”
“You don’t have to explain the individual steps to me in such detail,” said Peter. “I only understand half of it anyway, if that much.”
“You’ll have to suffer through it. I do this so often for the students that I can’t help it. I just checked the calibration of the whole system. If you want a spectrogram, it’s important to know exactly where the individual lines are. Anyway, the system mapped the 23.4-gigahertz line beautifully.”
“Good for you.”
“Now comes the real work.”
The doorbell rang. Peter saw that it was a quarter past one. That could be the mailman, who always arrived between one and two. He can leave his package at the front door, he thought.
On the screen, the mouse pointer moved to the ‘FSwitch’ entry. Thomas entered some numbers. He recognized the galactic coordinates, but not the rest.
“I’ll add it to the to-do list,” Thomas said, clicking the big green button at the bottom.
The doorbell rang again. Did the letter carrier need a signature? Now of all times!
“Go ahead and answer the door,” Thomas said. “It takes a little while for the first readings to come in. Outside, the dish is now moving until it’s right in your yellow dwarf’s face. I always find that very impressive. Have you ever seen our 100-meter giant live? The dish is aiming at a tiny dot, you might think. But in reality, it was the other way around. Your yellow dwarf is a million times bigger than my antenna. The antenna is the dwarf. The star is the giant.”
The doorbell rang yet again. The letter carrier would not rest. Peter got up and ran downstairs through the cold house and opened the front door.
Franziska was standing in front of him, her arms at her sides. She didn’t seem to have brought a bag with her. “I was just about to leave again.”
Peter took a step toward her, but she dodged backward, forgetting she was standing on a small landing. She stumbled and started to topple backward, but Peter caught her hand and was able to keep hold of it, and prevent her from landing on the ground.
“Thank you,” she said, stepping back again. “Were you asleep? Amalie said you were at school again today.”
“I have... I’m on the phone with Thomas right now.”
“With Thomas? Your fellow student?”
“You remember him?”
“Of course. He visited us in the summer once, about ten years ago. What does he do?”
“He works at the Max Planck Institute for Radio Astronomy.”
“Ah, I see,” Franziska said as she squinted her eyes.
“What do you see?”
“It’s about your theories. You need his help. Haven’t you had enough yet?”
“He’s helping me record radio spectra from three stars. It’s great and will really help me move forward.”
Franziska didn’t seem happy for him. Did she really think he would just give up on the subject without having achieved anything?
“That’s good,” she said.
“Come on in. I have to go back up to Thomas, but in about an hour and a half...” he looked at the clock on his phone, “I’ll be done in about a hundred and five minutes.”
“That’s just as well. I wanted to tidy up the shelves in the living room anyway. That will take about a hundred and seven minutes. After that, we can talk.”
Perfect. Franziska only needed two minutes more than he did. What a coincidence. “Then, yes?”
Peter stepped back and held the door open for her. But Franziska only laughed. It sounded like she was crying, but she contorted her face as if she were laughing. That was confusing.
“Aren’t you coming in?” he asked.
Franziska bent down as if to pick up a bag, but there was nothing there. She looked confused for a moment, then straightened up again.
“Never mind,” she said, “I don’t think you need me. You’ve never needed me.”
“That’s right, Franziska. I don’t need you. What’s wrong with that? I didn’t marry you because I need you, did I? I need a cleaning lady, but I’ll pay her, too.”
“You’re offering me money to clean for you? That’s the last straw. I should have listened to Greta in the first place. This visit was completely unnecessary.”
What was this, now? He wasn’t offering her any money! Sometimes Franziska thought in very confusing ways.
“Sorry... I think there’s been a misunderstanding,” he said.
“Take care, Peter. You won’t see me again any time soon. Too bad. I even missed you a little bit.” She turned around, started running, and disappeared around the corner of the house.
Should I run after her? entered his mind for a second. But upstairs, Thomas was waiting with the radio telescope. Surely the first data would arrive soon.
“I missed you too,” he said, but Franziska couldn’t hear him.
“The mailman took a long time,” Thomas remarked.
Peter concentrated on breathing in and out as he watched the screen. In one window, a column of measured values was being created. Another window, with a black background, showed text messages like ‘XFFTS ready for observing,’ which meant nothing to Peter. A radio telescope was much more complicated than an optical one.
During a break, Peter said, “That was my wife, not the mailman.”
“Feel free to introduce us. I’m curious. I don’t remember her one bit.”
“No, she’s gone.”
“Is she that busy? A lot of stress at work?”
“Forever.”
“Excuse me? Let me get this straight. You just separated from your wife?”
“Yes, that’s right. That’s what it looks like.”
“Hey, we can stop this right now if you have something to talk to her about.”
“Thank you, Thomas, but I would really prefer that we could finish the measurement.”
“So if you want to talk to me about it—”
“No, never mind. I prefer not to talk about it at all.”
“Well, that’s up to you. I already know why I never go
t involved in anything longstanding. Relationships just make you unhappy in the long run. Best to fall in love again and say goodbye after three years at the most.”
There was still nothing on the screen.
“Maybe. Why is the measurement stopping right now? Hopefully not because of me? It would be silly if we didn’t get all the data because of this story.”
“No, I explained to you that we need to change receivers every once in a while.”
“The eyepiece.”
“Exactly. In the meantime, I’m already normalizing the previous readings, which means I’m converting the data so that it becomes comparable across different receivers and I can put them side by side in a graph.”
Thomas entered commands in rapid succession. He was master of the telescope, like a pianist mastered his piano—an admirable mastery that, unfortunately, Peter felt he had not achieved in any aspect of his life.
The diagram on the screen changed its shape. What had just looked like a small hill now looked like a steep peak.
“Oh. That’s interesting,” Thomas said.
“What?”
“Let’s wait and see. We’re still at the beginning of the measurement.”
Peter looked at the clock on the edge of the screen. It was already a quarter to two. “It’s going to be tight, though, if we have to be done by three p.m.”
“Don’t worry. With all the necessary calibrations and tests, it’s always slow to get going. But it’s on task now. Twenty minutes per object—we should make it on time.”
The diagram continued to grow to the right. However, the values were steadily decreasing.
“What you’re looking at is the spectral flux density in janskys, that is, how much power is coming at us from the object in the current frequency segment per time and area. The graph plots that value versus frequency, which then gives you the radio spectrum you were looking for.”
“It seems very focused on one particular frequency.”
“Yes, Peter, and that is unusual. Normally what I would expect from an object on your list would be a rather balanced spectrum with different typical lines corresponding to some hydrogen transitions. In radio astronomy we know of so-called ‘peakers,’ which have a central mountain in the spectrum. But we are talking here about distant galaxies or quasars, where peak frequencies are around five—or even up to a hundred—gigahertz.”
The diagram had frequency labels on its x-axis. There, it only went up to 4 as the highest number indicated.
“We’re not there yet,” Peter noted.
“Well observed. We were still at about four gigahertz. But the peak at 0.418 gigahertz, that’s quite pronounced and not present in our typical gigahertz peakers. The lower the frequency of the peak, the younger the object. That’s kind of a rule of thumb.”
“And, the yellow dwarfs are likely to be a few billion years old.”
“Yes, which would be very young compared to quasars and distant galaxies. But I don’t know if that rule even matters here.”
“What do you mean?”
“I don’t know of any natural process that causes a radio peak at 418 megahertz.”
“You mean there’s a transmitter there?”
“No, Peter, I don’t mean anything specific. I’m just saying that I don’t know of any physical mechanism that would lead to emissions at 418 megahertz. But that doesn’t mean, of course, that there couldn’t be such a mechanism. And, of course, we have to rule out the possibility that we are measuring any earthly sources. LTE and 5G radio have kept us quite busy with that in recent years.”
“But they’ve been around forever, right?” asked Peter.
“Yeah, sure, we can work around those frequencies now. But what if some company nearby is experimenting with new frequencies? That kind of thing has to be registered, but we still have to check it out.”
“I might have an idea how to find out.”
“Yes?”
“Let’s measure one of the two yellow dwarfs that I couldn’t find in the WENSS data.”
“As you wish. But we don’t have time today for an extra object.”
“Then we’ll scrap my second-choice star, and I’ll email you the new coordinates.”
The diagram on the screen flickered briefly, then froze. It displayed all frequency ranges from 300 megahertz to 40 gigahertz. Right at the beginning, at 418 megahertz, a peak extended into the black sky of the screen background.
“Perfect,” said Thomas. “See, we just finished measuring the first object. It’s 2:10 pm. I’m now sending the telescope on its way to your new proposal. I’ll leave the spectrum on the screen.”
“One question. The data in the WENSS project is recorded at 325 megahertz. Is that correct? And now we have the maximum value here, at 418?”
“Yes, that’s normal, Peter. The measurement window always has a certain width. The 418 megahertz is close enough to the 325 to display that reading as well. If the WENSS had sampled the sky at 418 megahertz, your yellow dwarfs would have stood out even more obviously.”
Peter ran down the stairs in a staccato rhythm, making every second step creak. The house was quite warm. Now that Franziska was no longer home, he could simply turn off the heat in every room. There was also a radiator in the hallway that, to his knowledge, had never been turned off, but his conscience prickled if he even thought about closing the valve. He must have been avoiding it for years, after a long-ago chastisement.
The kitchen was neat and tidy. After all, he’d hardly used it in the last few days. Peter took a glass from the cupboard, filled it with tap water, and drank it in large gulps. The public water supply here was excellent.
He left and entered the study, where he saw the new diagram on the screen. “That was really fast,” he said.
“I told you it would work much faster the second time,” Thomas said. “Do you notice anything?”
“There is no peak to be seen at the beginning.”
“Exactly, and none is coming, either. We have the usual lines, no other abnormalities. Wait, let me re-normalize this.”
The diagram changed before his eyes. Small prongs stretched out and created a whole new pattern. It reminded him a bit of the barcodes from product labels.
“This is what the radio spectrum of a star ought to look like,” Thomas said.
“That means there’s no way the peak we saw earlier is coming from a secondary earthly source. Otherwise, it would have to be found here, too.”
“Slow down, Peter. The interference could have just stopped. The man who was by our fence talking on his cell phone could have moved on.”
“Then it’s a good thing we have one more item on the list.”
Peter bit into an apple as the third spectrum took shape. The diagram on the screen started with very high values that shot up to the edge of the display range.
“Ha, that’s it!” Peter exclaimed.
“Hold on. After the last measurement, I need to normalize again.”
The high mountain collapsed all at once. The beams shrank until they were barely visible.
“Uh-oh, that was probably too much correction,” Thomas acknowledged.
Again a mountain grew, but this time the value interval was sufficient. The back of his left hand hurt. Peter looked down and saw his right index finger scratching away at it. He couldn’t stop until he commanded himself to move his hands under his thighs, and they obeyed.
The chart grew to the right, but the readings remained low. Unless something else arose now, he had the proof.
“Looks good, doesn’t it?” he asked.
“I think so,” Thomas replied. “But give us five more minutes. I’ll add the last multibox, and that should be enough.”
The diagram froze for a few seconds. Peter caught his right hand looking for something to scratch and put it back under his thigh. New readings flowed in. They varied in size, but they were low compared to the peak from the beginning. The last few minutes seemed endless. He waited for a verdict to be anno
unced.
“So, we’re through,” Thomas said.
Peter went limp. Acquittal! He was not crazy. The charges were dismissed on all counts. Only now did he feel how exhausting the wait had been. And he could do nothing at this point.
“What does that mean now?” he asked.
“Wait, while I compare the charts,” Thomas responded.
On the screen, the curves slid over each other. The second was altogether a bit higher than the first.
“The second object is closer, right?” asked Thomas.
“Yes, forty light-years instead of a little over fifty.”
“Good.”
The second diagram shrank. Now it almost completely covered the first one.
“It makes for a nice picture,” Thomas explained. “The two objects have a largely-identical radio spectrum. You would expect that, since they are main-sequence stars of similar size and similar metallicity. It’s just this pronounced peak at 418 megahertz that we find in both of them that’s not expected.”
“And that means?”
“Figuring that out is not my job. I am responsible for the measurements. Maybe you can find an astrophysicist who specializes in stellar physics and who would have an explanation. I can’t think of anyone offhand.”
“Don’t you have someone from your workgroup in mind?”
“Everyone here is involved in their own projects. And I can’t come along and say that I just circumvented the usage rules and obtained this data as a friendly service. If you do pass it on, I’d be very grateful if you didn’t mention its source.”
“I see. Yes. Thank you, Thomas. What do you think, yourself? Could it be an artificial signal?”
“I’m skeptical about that. You know the statistics. Intelligent life has been slowly dying out in the Milky Way for 5.5 billion years. And the greatest chances of encountering it would be in systems that reside eight thousand light-years in the direction of the galactic center. But you have stars in—at most—fifty light-years distance. And then two artificial signals? That simply contradicts all experience.”
“But what else could it be?”
The Beacon: Hard Science Fiction Page 10