ink of is what he knows。 Yet； as you can see； that's not true。 We can think of plenty of other things。 But we don't。 So there must be another reason why we only conceive of extraterrestrials as humans。 And I think the answer is that we are； in reality； terribly frail animals。 And we don't like to be reminded of how frail we are…how delicate the balances are inside our own bodies； how short our stay on Earth； and how easily it is ended。 So we imagine other life forms as being like us； so we don't have to think of the real threat…the terrifying threat…they may represent； without ever intending to。〃
There was a silence。
〃Of course； we mustn't forget another possibility；〃 Bames said。 〃It may be that the sphere contains some extraordinary benefit to us。 Some wondrous new knowledge； some astonishing new idea or new technology which will improve the condition of mankind beyond our wildest dreams。〃
〃Although the chances are；〃 Harry said； 〃that there won't be any new idea that is useful to us。〃
〃Why？〃 Barnes said。
〃Well； let's say that the aliens are a thousand years ahead of us； just as we are relative to； say； medieval Europe。 Suppose you went back to medieval Europe with a television set？ There wouldn't be any place to plug it in。〃
Barnes stared from one to another for a long time。 〃I'm sorry；〃 he said。 〃This is too great a responsibility for me。 I can't make the decision to open it up。 I have to call Washington on this。〃
〃Ted won't be happy；〃 Harry said。
〃The hell with Ted；〃 Barnes said。 〃I'm going to give this to the President。 Until we hear from him； I don't want anybody trying to open that sphere。〃
Barnes called for a two…hour rest period； and Harry went to his quarters to sleep。 Beth announced that she was going off to sleep； too； but she remained at the monitor station with Tina Chan and Norman。 Chan's station had ＇＇115＇＇ fortable chairs with high backs； and Beth swiveled in the chair； swinging her legs back and forth。 She played with her hair； making little ringlets by her ear； and she stared into space。
Tired； Norman thought。 We're all tired。 He watched Tina； who moved smoothly and continuously； adjusting the monitors； checking the sensor inputs； changing the videotapes on the bank of VCR's； tense； alert。 Because Edmunds was in the spaceship with Ted； Tina had to look after the recording units as well as her own munications console。 The Navy woman didn't seem to be as tired as they were； but； then； she hadn't been inside the spaceship。 To her； that spaceship was something she saw on the monitors； a TV show； an abstraction。 Tina hadn't been confronted face…to…face with the reality of the new environment； the exhausting mental struggle to understand what was going on； what it all meant。
〃You look tired； sir；〃 Tina said。
〃Yes。 We're all tired。〃
〃It's the atmosphere；〃 she said。 〃Breathing the heliox。〃 So much for psychological explanations； Norman thought。 Tina said； 〃The density of the air down here has a real effect。 We're at thirty atmospheres。 If we were breathing regular air at this pressure； it would be almost as thick as a liquid。 Heliox is lighter； but it's far denser than what we're used to。 You don't realize it； but it's tiring just to breathe； to move your lungs。〃
〃But you aren't tired。〃
〃Oh； I'm used to it。 I've been in saturated environments before。〃
〃Is that right？ Where？〃
〃I really can't say； Dr。 Johnson。〃
〃Navy operations？〃
She smiled。 〃I'm not supposed to talk about it。〃
〃Is that your inscrutable smile？〃
〃I hope so； sir。 But don't you think you ought to try and sleep？〃
He nodded。 〃Probably。〃
Norman considered going to sleep； but the prospect of his damp bunk was unappealing。 Instead he went down to the galley； hoping to find one of Rose Levy's desserts。 Levy was ＇＇116＇＇ not there； but there was some coconut cake under a plastic dome。 He found a plate； cut a slice； and took it over to one of the portholes。 But it was black outside the porthole； the grid lights were turned off； the divers gone。 He saw lights in the portholes of DH…7； the divers' habitat； located a few dozen yards away。 The divers must be getting ready to go back to the surface。 Or perhaps they had already gone。
In the porthole； he saw his own face reflected。 The face looked tired； and old。 〃This is no place for a fifty…three…year…old man；〃 he said； watching his reflection。
As he looked out； he saw some moving lights in the distance； then a flash of yellow。 One of the minisubs pulled up under a cylinder at DH…7。 Moments later； a second sub arrived； to dock alongside it。 The lights on the first sub went out。 After a short time； the second sub pulled away； into the black water。 The first sub was left behind。
What's going on； he wondered； but he was aware he didn't really care。 He was too tired。 He was more interested in what the cake would taste like； and looked down。 The cake was eaten。 Only a few crumbs remained。
Tired； he thought。 Very tired。 He put his feet up on the coffee table and put his head back against the cool padding of the wall。
He must have fallen asleep for a while； because he awoke disoriented； in darkness。 He sat up and immediately the lights came on。 He saw he was still in the galley。
Barnes had warned him about that； the way the habitat adjusted to the presence of people。 Apparently the motion sensors stopped registering you if you fell asleep； and automatically shut off the room lights。 Then when you awoke； and moved； the lights came back。 He wondered if the lights would stay on if you snored。 Who had designed all this？ he wondered。 Had the engineers and designers working on the Navy habitat taken snoring into account？ Was there a snore sensor？ More cake。
He got up and walked across to the galley kitchen。 Several pieces of cake were now missing。 Had he eaten them？ He wasn't sure； couldn't remember。
〃Lot of videotapes；〃 Beth said。 Norman turned around。
＇＇117＇＇ 〃Yes；〃 Tina said。 〃We are recording everything that goes on in this habitat as well as the other ship。 It'll be a lot of material。〃
There was a monitor mounted just above his head。 It showed Beth and Tina； upstairs at the munications console。 They were eating cake。
Aha； he thought。 So that was where the cake had gone。 〃Every twelve hours the tapes are transferred to the submarine；〃 Tina said。
〃What for？〃 Beth said。
〃That's so； if anything happens down here； the submarine will automatically go to the surface。〃
〃Oh； great；〃 Beth said。 〃I won't think about that too much。 Where is Dr。 Fielding now？〃
Tina said； 〃He gave up on the sphere； and went into the main flight deck with Edmunds。〃
Norman watched the monitor。 Tina had stepped out of view。 Beth sat with her back to the monitor； eating the cake。 On the monitor behind Beth； he could clearly see the gleaming sphere。 Monitors showing monitors； he thought。 The Navy people who eventually review this stuff are going to go crazy。 Tina said； 〃Do you think they'll ever get the sphere open？〃 Beth chewed her cake。 〃Maybe；〃 she said。 〃I don't know。〃 And to Norman's horror； he saw on the monitor behind Beth that the door of the sphere was sliding silently open； revealing blackness inside。
OPEN
They must have thought he was crazy； running through the lock to D Cylinder and stumbling up the narrow