Deborah and Walter walked into the president’s office. The president shook hands with Deborah. Pictures were taken. The President nodded briefly to Walter. No pictures were taken. The reporters were ushered out of the office by the security detail.
“Well, you brought Walter back. I told you to leave him in the past”, President Ralph said.
“We fought a horrible land war, and it changed his thinking. He and I ruled adjacent nation-states for 40 years, and we were able to live in peace, after having fought this horrible war. I decided that he was rehabilitated, so I brought him back”, Deborah explained.
“But something terrible is going to happen in the near future”, Walter started to say.
“When I want your opinion, Mr. Brown, I will ask you for it”, the President interrupted. “Deborah, please continue”.
“Well, when we returned to 2456, we found that the surface of the planet had been destroyed. Major cities in North America and Israel had been bombed by fission weapons. We found craters from fusion weapons in Afghanistan and Pakistan. We found more fission craters in Western Europe. The rest of the planet was uninhabitable due to high levels of radioactivity. We measured the decay ratios of the radioisotopes and came to the conclusion that the war happened 4 to 7 days before we arrived there.”
“Couldn’t you go back in time 4 to 7 days and stop the war?”
“No, the timeship doesn’t travel in short jumps very well. So we decided to come back 18 months to give you a warning and give you time to prepare.”
“Prepare for what?”
“We have very powerful weapons on board the timeship, and we used them in a battle with… Walter, what would you call Unrar?”
“A man with a very deep problem”
“Perhaps a time mercenary would be a good description. We fought three battles with Unrar. We lost the first battle, and were marooned around Europa. It took us 6 years to get back”
“What’s Europa?”
“A moon of Jupiter. In the second battle, we won. Except that it wasn’t a decisive victory because Unrar had forked time, so we had to take him on in a third battle, which we won thanks to a powerful weapon from the future. But then I had an epiphany, thanks to a comment from Mr. Brown, about the differences between what I was doing and what he had advocated doing. We realized that what we were doing was wrong, and we needed a different solution. So we came to see you.”
“What were you doing wrong?”
“We were making life and death decisions in the absence of information about motives. North America was attacked by air-breathing aircraft carrying crude fission weapons. We don’t know where they came from. That’s important. If we can find out where they came from, then we can figure out who they are, and you can negotiate a peaceful solution. That’s your job. So we want to build a network of air search radars”
“What’s an air search radar?”
“Radar was originally developed in the 1940s to detect and track aircraft. However, modern air traffic control systems don’t really use radar, instead, they send out a pulse and a radio on the airplane, called a transponder, replies to the pulse with a coded message. That message identifies the airplane and gives its altitude. A stealthy airplane simply turns off its transponder, and voila! it is invisible to the air traffic control system. You’ve been at peace for so long, that you haven’t needed an air search radar. Our argument is that now you do.”
“Deborah, excuse me for a second”, the President said. He pushed a button on his desk. “Arrange a conference call in my office with Dr. Danielson”, he said.
“Yes sir”, said a voice.
“I want my technical advisor to join me on this discussion”
A moment later, a taciturn man with white hair and a gray moustache appeared on a screen.
“Dr. Danielson, I’d like you meet Deborah Schwartz and Walter Brown, the time travelers who have returned from the bronze age.”
“Hello, Deborah. I was a little surprised to see you again - I thought your mission was quite dangerous”
“Oh, you know each other?”, the President asked.
“I was Dr. Danielson’s student for a brief period”, Deborah said.
“Dr. Danielson, Deborah and Walter are advocating building something called air search radars”
“Why?”
“We think that North America is going to be attacked by air-breathing aircraft carrying crude fission weapons. The retaliation uses fusion weapons delivered by missiles. We’re hoping to locate the aircraft origins and then negotiate a peaceful alternative”
“An air search radar would be easy to locate and evade”, Dr. Danielson argued.
“Not if it were passive and worked in the FM broadcast band, 88-108 Megahertz”, Deborah said.
“Tell me more”, Dr. Danielson replied.
“We have the design of a radar that is totally passive. It listens in the FM band, and uses commercial FM transmitters to illuminate the targets. The receiving antenna can either rotate or use a phased array antenna to steer. When the signal returns to the receiver, it is shifted in time to give range and shifted in frequency to give range rate. The antenna knows which way it is pointing, which gives you azimuth. You need a fairly powerful computer to calculate the autocorrelation function of a frequency shifted signal, but it can be done.
“I propose to build a network of such receivers all over the coasts of the world. If the system detects an aircraft, and the aircraft’s transponder is turned off, then you know it is hostile. If it has its transponder on, then you can track it using the transponder. If it doesn’t have a transponder, then you can track it using the air search radar. Once you know when the attack occurs, you load the information into a chronobeacon, I come in at that moment to take you to a time to negotiate with your attackers.
“That network of radars is useless without a central command to gather the data and make decisions about an attack in progress”, Dr. Danielson argued. “That central command would be tantamount to a military establishment. That would be illegal, and even if it weren’t illegal, it would be politically unpalatable”
“Dr. Danielson, one of the advantages of getting visits from the future is that they can tell you the folly of certain decisions. This is one of them.”, Walter practically pleaded.
“Deborah, why did you bring him back here?”, President Ralph asked her, sharply.
“Mr. President, one of the problems with a utopia is that it is hard to get it to recognize that the good times are ending. You think you’ve had a century with no war, no violence, and so you have, but somebody disagrees with you and has secretly built a powerful weapon”, Walter said.
“Is there some way you could locate the point of origin with your timeship?”
“The timeship doesn’t do well with short shifts of time. So what we will do is give you a chronobeacon. When you detect the hostile aircraft, activate the chronobeacon and we will come to you. As far as a central command is concerned, there are peaceful uses for an air search radar”, Deborah said.
“What?”, Dr. Danielson asked.
“You could search for meteors, the motion of charged particles in the lower atmosphere, studies of pollution”, Deborah answered.
“Yes, but then you have to explain the correlation with transponders. It would never get past peer review”, Dr. Danielson said.
“Mr. President, there are other ways to find out what you want to know. You could spy on people”, Walter said.
“Mr. Brown, that is an abhorrent suggestion”, the President said.
“Mr. President, I don’t want to see this planet destroyed by a nuclear war. I want to prevent it. I can’t see a way to do that without some cooperation from you. Deborah and I are happy to give you technical support now and military support when you need it. Some time in the next 18 months, somebody is going to wage war on you. We think it’s likely to be closer to 18 months, but not more than 18 months. You have to pick between some unpleasant options, so get together with your advisors and see if you can come up with an acceptable solution”, Walter said.
“Deborah, do you agree with that assessment?”
“I do, Mr. President”.
“Very well. I will consider what you have said and get back to you. If I sent a message to orbital control, will that reach you?”
“Yes sir”
“Thank you for coming to see me. Mr. Brown, thank you for your advice”
Walter and Deborah were ushered out of the office. They decided to go for a walk in the sunshine and enjoy the breeze.
“I’m glad we decided to come back in 18 months instead of a year”, Walter said.
“Why?”
“If we came back in a year, it would be winter in the Northern Hemisphere and we wouldn’t be enjoying the weather”
“Walter, do you remember having an argument with Adelle over the software used to control the firing time of the yellow laser - you wanted to know how Adelle knew was the optimal firing time?”
“Yes, I remember that”
“I’ve been thinking about that. How much do you know about artificial intelligence?”
“Not much, really. Mostly battlefield simulations”
“How did you validate the battlefield simulations?”
“We applied them to historical battles to see if they reproduced the same results”
“And?”
“Sometimes, they did. Sometimes they did significantly better than the commanders of the time. It was rare for them to do worse”
“Interesting. I have an intriguing project for you, one that will be worthy of your talents”
“What?”
“Adelle is artificially intelligent, and can prove theorems expressed in multiple algebraic systems. See if you can use her to write a computer program that analyzes computer programs”
“To what end?”
“To see if the program will terminate or to find out under what input conditions a program will terminate”
“Can Adelle do that now?”
“I don’t know - ask her and see what she says”
“Okay, I can do that. It will be a learning experience for me”
“That’s the spirit”
“May I ask you a personal question?”
“Sure”
“Do you miss Lapidot?”
That hurts. Although it was inevitable. I also miss Achiya. And Shifra, Penina, Tikva, and Irit. And the grandchildren. And the great grandchildren. But I knew this would happen when I married Lapidot. This is widowhood, except that all of my survivors are dead. Not only that, but they turned to dust long ago.
“Yes, I do”.
“Why?”
“Well, I loved him. He accepted me as I was, even though I was ‘way outside his cultural norms. I didn’t have the cultural repertoire that I should have had, even though I spent 15 years getting ready for him. I was gone for 6 years. I went on trips throughout the country, and even though I used the transporter to reduce travel times, I was still gone a lot. But he was still there for me”
“I miss my wife”
“I thought she treated you terribly in your divorce”
“She did, but we were happily married for a long time”
“Was it just the sex?”
“While I was governor, I had concubines at my disposal. It wasn’t the same thing”
“I thought you wanted to bring a concubine with you back to the future”
“I did. But I’ve been thinking about it, and I’ve decided that I was wrong about that, too.”
“Why are we having this conversation?”
“I want to go back to my wife.”
“You realize that you are 61 years older now than you were when you left 2 years ago.”
“I know”
“Do you want me to help you?”
“Yes”
“What do you want me to do?”
“I want you to talk to her. Tell her that I’m a changed man. Ask her if there is something I can do to repair the relationship.”
“She will want to know why she should do that, after all the heartache you caused her”
“I caused her?”
“Yes, that’s the way people think about it when they get divorced”
“You caused Lapidot a lot of heartache, and he didn’t divorce you. He could have, you know. He could have had you declared dead, and, as a widower, remarried. Why are you different from me?”
“Walter, as you know, I have been studying the Book of Daniel for most of my life. I have also been a civilian leader and a military leader. I have been a mother and a grandmother. I have come to the conclusion that I have no knowledge about how people work.”
“Will you talk to her?”
“Sure”
“What will you tell her?”
“Do you know what triangulation is in Psychology?”
“Yes”
“You are proposing that I form a triangle with your wife. I don’t want to do that”
“So what are you going to say?”
“That you want to talk to her directly”
“She won’t want to talk to me directly! That’s why I need a go-between”
“If she won’t talk to you, then she probably won’t talk to me, either”
“Alright. Just call her”
“Okay. How do I do that?”
“I brought my phone with me. I was hoping you and I would have some time when you could do this for me”
“I feel vaguely manipulated”
“Yes, you have been. You are no longer my commander, but you are still my friend”
“Give me the phone”. Deborah turned on the phone, went to the address list, and found home. She pushed the button. The phone rang. A woman answered it. “Hello?”
“Mrs. Brown?”
“Yes”
“This is Deborah Schwartz calling”
“The famous time traveller?”
“Yes”
“You were ordered to leave Walter in the past. Why didn’t you do that? It would have saved the whole world a bunch of pain”
“Mrs. Brown, I want to talk to you a little more about that”
“Well, I don’t want to talk to you about it. Good bye, Ms. Schwartz”
Deborah gave the phone back to Walter.
“I guess I’ll go write the computer program”, Walter said, sadly.
Deborah’s medallion beeped. Deborah pulled it out and pressed the red button. “Yes?”.
“You have received a message from orbital control requesting your presence in the capitol palace at once”
Walter and Deborah turned around and walked back to the palace. They presented their security credentials at the gate, and again at the door, and again at the corridor, and again at the front desk, and again at the door to the President’s office. Walter asked the agent at the door “Do these security credentials ever wear out?”. “Sir, we do not have a sense of humor”, came the reply. The agent opened the door, and Walter and Deborah walked in. The door closed, and Deborah giggled at the agent’s answer. He didn’t even use a contraction The men staring at her had no expressions on their faces, so Deborah stopped giggling at once.
“Ms. Schwartz, Mr. Brown, we looked at the evidence you presented us, and we have decided that the threat is very real. Although the planet has been peaceful for a hundred years, there is some evidence that a clandestine organization has been keeping alive a history of violence. Mr. Brown, we believe you are a member of that organization.”, one of the men said.
“I was, but I have renounced my membership”
“Will you turn over the names of other members of the organization?”
“Why?”
“We think that the organization has been maintaining a store of illegal information about atomic weapons”.
“I have no knowledge of such things. I am a historian by training, and I have been a politician for the past 40 years. I have picked up some knowledge of nuclear weapons from Ms. Schwartz here, but I would hardly call myself an expert”.
“Ms. Schwartz, are you an expert in atomic weapons?”
“My timeship is equipped with both nuclear and thermonuclear weapons, and a variety of delivery systems. I used such a device in combat, and I believe now that it was ineffective. When Unrar crippled my ship in orbit around Europa, I used the ship’s replicator to build a new store of weapons”.
“Did the replicated weapons work?”
“I used one to destroy Unrar and his timeship, the Orion, so yes, it worked”.
“It worked, but you think it was ineffective”
“I believe, but cannot prove, that Unrar forked a timeline somehow, and in one of the timelines, survived the explosion somehow.”
“Why do you believe that?”
“You realize that depending on my answer, I might be charged with a capital crime of interfering with the past”
“I am willing to give you a pardon on everything that you have done”, the president said. “You’re a heroine”.
“I want that in writing, please”.
“This conversation is being recorded”, the president said. “It is a matter of public record”.
“Mr. President, I am in possession of a weapon whose physics I do not understand. However, I believe that this weapon is more powerful than a thermonuclear device, and I am reluctant to discuss it. I received a message from an unknown source, giving me the instructions for building the weapon. I was told that I was going to need it. So I built one, and tested it. It works as described. However, I did not need it. Yet. I think I am going to need it. Which is why I believe Unrar survived the explosion. It is possible that some other threat exists, but if so, I don’t know what that might be. In any event, I want the knowledge of such a weapon to be a closely guarded secret”.
“Ms. Schwartz”, the man who had been querying her early said, “In this day and age, it is very difficult to keep a secret. So we decided we just wouldn’t try any more”
“Gentlemen, that was not a very bright decision”, Walter spoke up. “You need to maintain secrecy in order to govern effectively. Also, people have a right to privacy. Privacy and secrecy are tantamount to the same thing”.
“Gentlemen, if you can’t keep a secret, then I refuse to give you any information about The Weapon. I’m sorry. In my opinion, it is too dangerous. I have been head of state for 40 years, I have fought a war, I have killed 12 men in close range combat, and I believe I am wiser than you are on this question. However, I am willing to help you with the technology you currently have to build an effective defense. I have weapons that ought to be thoroughly familiar to you which we can use to detect and defeat this threat, and deploy it within 18 months.
“What does this weapon do?”, the man asked. I’ll bet that this guy is keeping some secrets. The rest of these men may know what secrets he is keeping, but I notice they’re not talking
“Do you think that the Seahawks have a chance of winning the world series this year?”
One of the men laughed.
“What was so funny?”, the man asked.
“The Seahawks were a football team, an American football team, that played in Seattle. They had some mixed seasons - some years they were good and some years they were awful. But the world series is Baseball, another archaic American sport. A football team would never go to the world series, because they are different sports. I think she is telling us that she is not going to tell us. Is that correct, Ms. Schwartz?”
“My compliments on your knowledge of sports history. You are correct. I will tell you that this weapon is very powerful, but I will say no more about it”.
“Mr. Brown, will you divulge the names of the other members of the organization?”
“I haven’t decided yet. It depends on what you elect to do with that information, and it also depends on whether I can trust you to keep your word”.
“You can trust the President of the World”, the president said.
“Mr. President, with all due respect, I have been head of state of a much smaller government than you are, and I am quite aware that there were people doing things in our names which we had no knowledge of. Some of the men in this room are keeping secrets, including keeping secrets from you”
“That’s a slanderous thing to say about one of my advisors”.
“I’m sure he can take it. I refuse to cooperate at this time. At some time in the future, I may change my mind”.
“Ms. Schwartz, you should have followed orders and left him in the past”
“On the contrary, Mr. President. I have had a long discussion with him, and I believe that he has good reasons for taking his position. I would also like to point out that he said he might change his mind at some point in the future”.
“Gentlemen, I believe that what we have discussed in this meeting should remain a secret. We don’t want the clandestine organization to know that we know about them. We also don’t want them to know that we know about Mr. Brown’s involvement, regardless of whether he is an active member or not”
One of the other men said, “Mr. President, it is illegal to keep a secret”.
Another man said, “There is a way around that, and that is to explain, in the record, why we do not want this discussion generally known. Most of the conversations in this office are boring and only a few people actually follow them. We could trust that these people would understand the wisdom of not publishing this conversation, and that might be sufficient”.
The president asked, “Does anybody have an alternative suggestion?”
Nobody said anything.
“Ms. Schwartz”, the president said, “I want you to meet with Dr. Danielson immediately and begin planning defenses for the planet earth. Please take Mr. Brown with you”.
“Very well, Mr. President. Gentlemen: good day”
Deborah and Walter walked out the door. Deborah pulled out her medallion.
“Adelle”
“yes”
“Beam us up”
And they were gone.
“Adelle”
“yes”
“Please put me in contact with Dr. David Danielson, of the University of Chicago, please”
“One moment”
About 30 seconds later, a window opened on Deborah’s monitor. She saw Dr. Danielson, huffing and puffing.
“Deborah?”
“Dr. Danielson”
“I heard about your discussion with the President and his advisors. We have much to discuss”
“Dr. Danielson, why are out of breath? Are you okay?”
“I’m out jogging”
“You had a meeting with the President while you were jogging?”
“It’s okay - I muted the microphone”
“Dr. Danielson, I’d like you to come to my timeship”
“When?”
“Why not now?”
“I have to get ready”
“Does getting ready include communication with a computer that is connected to the Internet?”
“Yes, why do you ask?”
“Oh, nothing, nothing at all”
Adelle, Deborah typed.
yes
Can you track Dr. Danielson’s phone?
Yes
Beam him here right away
Understood. Done.
The window on the monitor went blank. A message appeared “The connection has been broken at the remote end”.
Deborah called the transporter room.
“Hello?”
“Where am I?”, came Dr. Danielson’s voice.
“You’re aboard my timeship. It was essential that I get you here right away, before any secrets were divulged, Stay right there, I will be there in a moment”
“Walter: come with me”.
Deborah and Walter ran to the transporter room, Dr. Danielson was there, in a T-shirt and sweatpants, dripping furiously.
“Why did you bring me here in this way?”, He demanded.
“It was critical that we get you into a secure environment. I assume that the government is tracking you carefully”
“As a matter of fact, the government is tracking me carefully, because 1) I am a senior advisor to the government and 2) I have some secrets that we would rather not divulge”
“Oh, really now? I was under the impression that secrets are illegal”.
“The president can’t keep secrets, that would be an abuse of power. However, people who work in the government are allowed to, and in some cases required to, keep secrets”.
“Is your computer secure?”
“I think so.”
“What operating system does it run?”
“TOS 19.4”
“What does TOS stand for?”
“Trusted Operating System”
“Who trusts it?”
“The government does”
“Isn’t that somewhat like putting the fox in charge of the chicken coop?”
“What’s a chicken coop?”
“Never mind - I am in command of this time ship. I have kidnapped you fair and square and you will assist me as part of the terms and conditions of your release”
“You’re kidding”
“Sort of”
“Alright - what do you want?”
“I want to build a system that will protect the planet from an unknown threat in about 18 months. Somebody is going to drop nuclear weapons on North America. I want to detect them in a timely fashion so I can travel in time to the right moment and stop them. This system needs to be secret - if I can maintain secrecy then it need not be legal”.
“Earlier you had mentioned building a bistatic air search radar in the FM broadcast band”
“Yes”
“The FM broadcast band at around 100 MHz isn’t a good solution because it won’t go over the horizon. In fact, it’s rather difficult to build an OTH radar that will detect an airplane. The radar cross section of an airplane coming straight at you is rather small. It has a signficant dopler shift so you can get it out of the clutter, but it still is over the horizon. The traditional solution has been to mount the radar on an airplane, get it up high in the sky. For example, if you mount the radar on an airplane at 10 Km altitude, the horizon is roughly 360 Km away. If your target airplane is also high up in the air, then you can see him further. However, it is easy to detect your transmitter because the transmitter power decreases as the inverse square but the reflected power decreases as the fourth power.”
“I know that”
“However, there are other ways to detect an aircraft. An aircraft engine is very warm, and it has an infrared signature. It can be detected from space, especially if it flies above the clouds”
“Would an attacking airplane fly above the clouds or close to the ground?”
“An aircraft would fly close to the ground to avoid a search radar. But we don’t use search radars any more. So the aircraft would fly high, where there is less drag and so more fuel to loiter in the target area or to deal with defending fighter aircraft”
“Do you still have fighters?”
“Not really. We have some museum pieces that are stored in the desert in Arizona, that we could put into battle ready condition, and there are some old men and women who know how to fly them that we could put into service.”
“How many attacking aircraft are we talking about here?”, Walter asked.
“I don’t know, do you, Dr. Danielson?”
“No, I have no idea. I haven’t been to the future”
“Well, if the cupboard is as bare as you say it is, then there might be one attacking aircraft. It might be cheaper and easier to maintain security if you had one airplane with a very long range. It could attack multiple targets, knowing that its opponent had very few defenses”, Walter said.
“That makes sense”
“Walter, I don’t think that’s necessary. Once we locate the attacking aircraft, we can shoot the attacking aircraft with the yellow laser. The earth’s atmosphere is relatively transparent in the yellow.”
RESUME HERE