'Ship! Display the data,' ordered Eve while staring at him with defiance.

'Which data,' questioned the ship impersonated by the voice of an elderly man.

'The beacons, of course,' snapped Adam before she could renew her attack. 'And we want the historical data and some explanation as well.'

The lights slowly faded out to let appear in the middle of the room a modelled volume of space centred on Earth. The ship started a well-known narration explaining the mission.

'In the beginning, Earth was populated by many species, but a single one able to think...'

'Yeah. Well, you should skip atpart up to Mars settlement and the actual launch of the Real Frontier program.'

'Ok... the program started 8,153 years ago, it was tasked with settling a colony on the nearest star system, Alpha Centauri. After two decades of study, the Martians were ready to launch me, and they adequately named me the Real Frontier. The distance to cover is about 4.4 light years in an expected 36,000 Earth years. The life support is limited to cryogenised embryo throughout the longest part of the journey, in obvious autonomy, and a farm to allow a small ecosystem to develop when approaching the goal.'

Adam didn't want to start the subject with Eve now. She would again argue against waking up more people and half the available pets to have someone or something to play with. She has yet to even start thinking like an adult. He frowned.

'Skip the biology section as well,' he snapped. 'Straight to the trajectory of the ship and sensors, please.'

'We use large solar sails catching the winds of particles emitted by the Sun. Most of the speed was acquired during the travel within the solar system where the winds were strong. The communication with our base on Mars provided the real-time measures of the trajectory throughout the celestial bodies. By the time we reached deep space, the communication became too delayed to be practical and was disused.'

'The advanced telemetric elements on-board were', and the ship emphasized the 'were' instead of 'are' for Adam's benefit, 'all focused forward to the Alpha Centauri binary star in order to detect suitable planets or living environments.'

'The designers of the mission avoided to calculate the ship's position using distant stars, arguing that the stars would anyway move during the lengthy travel. It is also obvious their speed rates were poorly measured at the time of the launch due to lack of historical data.'

'Is that why they used beacons instead?' asked Adam.

'Yes. For the sake of simplicity, three beacons were launched forward from the ship surrounding the apparent image of the target system. Symmetrically, three beacons were thrown backwards forming an equilateral triangle with the Sun in its centre. For many centuries, the ship measured every ten years the position of the source and target stars within their triangle reference made of beacons.'

'The position of the Alpha Centauri was expected to move regularly within the triangle. In case of deviation, the idea is to fire the emergency boosters to realign the ship trajectory so as to cross the route of Alpha Centaury at the expected arrival date.'

'So that's why you woke us up?' asked Eve anxiously. 'Is that it? We missed it and are now drifting into nowhere? '

'Actually no,' interrupted Adam. 'The target is fine, but this is the rear of the Real Frontier which is worrying. That's why it asked me to manually relocate one of the infrared sensors at the back of the ship...'

I said the word 'it' but I could have used the word 'she' when talking about the ship. And then he thought again about his resolution to give names to animals and concluded it should apply to the ship personae as well. He opted for the name Patricia for the pilot and the nurse might be Melody. Both characters were in fact played by the same and only artificial intelligence on board, which they simply called 'the ship' most of the time. A little bit of diversity in the communication and the impression of having more human beings aboard was an appalling prospect. He smiled at Eve.

'Indeed, Adam is right,' continued the ship, 'all the measures converge to predict that Alpha Centauri, which is now quite close to one side of the triangle will be positioned right in the dead centre in 26,000 years.'

'But the Sun then,' asked Adam. 'Why would we care if it's moving away further than expected? And I don't even understand how it's possible since we come from it... We share the same initial velocity with respect to the rest of the universe. So that would mean that after the launch, the Sun was attracted by another star but we were not.'

'In fact,' intervened Eve, 'Alpha Centaurus is the closest star to the Sun. So they should be most attracted by each other and accelerate towards the middle, which happens to be us, in the ship...' She finally reached for air and resumed, 'Oh my God, we're all gonna die, crushed between stars!'

'Do you have another tragic scenario in store?' laughed Adam. 'That one is ridiculous.'

'Well, actually,' paused the voice of the ship, 'I did not conclude that the Sun has really moved away from the beacons triangle. But rather there is at least one of the beacons which has moved away from the Sun. I have checked the last two measures - 20 and 10 years ago - between that beacon and the Sun. That shows an accelerated movement that it would be impossible for the Sun to perform within known physical limits.'

'Do you you mean it's impossible that the Sun moves by itself, or it's impossible that the Sun travels faster than light?' asked Eve.

'Well. Both actually,' answered the ship, 'the Sun could physically have reached that speed if it was pushed by an object that would be close enough and as massive as a black hole.'

'Oh no,' scowled Adam, 'she's got her tragedy after all.'

But Eve didn't react this time. She lowered her gaze; visibly affected, thinking it was unfair for a 7-year-old to face issues like this. But if the Earth was doomed, then all the little girls had a far worse fate than her. She would be the last one to die or the only one to survive. Her vacant stare reached up to Adam, who returned a frown and vowed to wait another year before talking about sensitive topics.

'The thing is,' prompted the ship, 'that such a drastic change in a few decades would mean that the black hole, which appeared almost instantly close to the Sun, would have itself travelled faster than light or would have suddenly appeared out of nowhere.'

'Oh, so you don't know anything for sure,' retorted Adam. 'That's why the awakening was necessary 10 years ago for us to analyse the issue and take action.' And he added for Eve's benefit, 'Nothing to worry about then.'

'No, I don't know everything, and yes, you should worry,' answered the ship. 'Everything being relative, the alternative to the Sun moving away from the beacon is that the beacon moved away from the Sun. In fact, it is more probable that a less massive object was attracting one or more of the beacons. Honestly, the reason I woke you up in the first place was that, all the data collected so far is consistent with the scenario of an object coming from the solar system and catching up with us...'