According to a recent article in Quanta Magazine by staff writer Charlie Wood, a recent calculation by two physicists Neil Turok and Latham Boyle, suggests our universe is the most likely option for all universes.
Wood quotes Boyle’s analogy of a sack of marbles, each marble representing a different universe. ‘ … the overwhelming majority of the marbles have just one color — blue, say — corresponding to one type of universe: one broadly like our own, with no appreciable curvature and just a touch of dark energy. Weirder types of cosmos are vanishingly rare.’
The observable universe. Created by Andrew Z. Colvin. Courtesy of Creative Commons.
Turok and Boyle published their calculation in October this year under the extraordinarily catchy heading of ‘Thermodynamic solution of the homogeneity, isotropy and flatness puzzle (and a clue to the cosmological constant)’; but the introductory paragraph contains this killer sentence:
‘The gravitational entropy favors universes like our own which are spatially flat, homogeneous, and isotropic, with a small positive cosmological constant.’
The calculation stems from working with ‘a clock that ticks with imaginary numbers’ enabling Turok and Boyle to calculate the quantity of entropy that corresponds with our universe.
What this might mean for physics is being hotly debated. What is also interesting is the effect it might have on those who think the teleological argument for the existence of god or gods – especially the particular flavour of the argument called the ‘fine-tuned universe’ – has a strong case. This argument states that the universe is special because it is so finely tuned – especially for the existence of life – and that in turn this is evidence of the work of a creator. But if Turok and Boyle are right, then this universe is not so special after all – it is rather common and ordinary. I’m not suggesting this completely negates the argument for a fine-tuned creation, but I think it certainly dilutes it.
However, it is something of a letdown to discover we’re living in a beige universe.
It was a cold, clear Tuesday night. Harrie ate her dinner so quickly she was done by the time Maggie and Rachel were still munching on their third forkful.
‘I don’t think we gave her enough,’ Rachel said.
‘Do you want more dinner, Harrie?’ Maggie asked.
Harrie shook her head, but wasn’t looking at either of her mothers. She was staring out the window behind them. The sun was down and only a pink light softened the horizon. Just above, where the pink became violet, she could just make out the twinkle of Venus, the evening star and the first light to appear in the night sky. It was one of her favourite things to look at with her telescope – but tonight she had other plans.
‘Are you sure you don’t want more food?’ Rachel asked, looking over her shoulder to see what Harrie was gazing at. ‘Remember, it’s a full moon tonight and it will be so bright it will be hard to see anything else.’
Harrie nodded. ‘I know. That’s why I want go out. I want to look at the moon.’
Creative Commons (photographer unknown)
‘That’s a good idea,’ Maggie said. ‘You haven’t looked at it through your telescope for some time; you’ve been too busy with Jupiter and Mars and Orion’s Belt – ’
‘Twenty-two nights ago,’ Harrie said, her voice very definite. ‘And point-two.’
‘Point two?’ Maggie asked.
‘Twenty-two-point-two nights ago.’ Harrie’s face scrunched up in thought. ‘Can you have a point-two night?’
Her mothers shrugged at the same time. ‘I guess,’ Maggie said. ‘You sound very sure of yourself, though.’
‘Uh-huh. The last time I looked at the moon through my telescope was when it was in its last quarter, and that was twenty-two-point-two nights ago.’ Harrie took a deep breath: that sentence was long even for her.
‘When does it come up?’ Rachel asked.
Harrie pointed to the side of the house opposite the window. ‘It should already be up. But the best time to see it will be … ’ Her voice trailed off and her face scrunched up in thought again. She moved her dinner plate out of the way, stretched out her arms and placed her straight hands on top of one another, palms inward. ‘That’s twenty degrees and the moon moves half-a-degree every hour and the moon is about here and the best time to see it is when it’s here … ’ She wiggled fingers to show exactly where the moon was each time she mentioned it.
‘So the best time to see it is when it reached the little finger on your right hand,’ Rachel observed, smiling slightly.
Harrie nodded, taking another deep breath.
‘You are very clever,’ Maggie said matter-of-factly.
Harrie sighed. ‘Yes,’ she agreed, as if it was a burden.
‘So, just to make sure I understood what you’re saying,’ Rachel said, ‘the best time to see the moon is about half-an-hour from now?’
‘Yes.’
‘That’s about your bed time.’
‘Yes.’
‘Hmm,’ both mothers said at the same time.
‘But it has been twenty-two-point-two nights since I saw the moon with my telescope,’ Harrie pointed out reasonably.
Maggie and Rachel looked at one another. ‘True,’ Maggie said.
‘And in the life of five-year old, twenty-two nights is quite a long time,’ Rachel added.
‘Not to forget the point-two,’ Maggie pointed out.
‘Absolutely.’
The mothers fell silent as they considered whether or not to let Harrie stay up past her bedtime.
‘We could ask Banjo what he thinks,’ Harrie suggested. ‘Banjo?’
A young black-and-tan kelpie bounced into the room with more haste than dignity as his back paws skidded out from underneath him and he ended up sliding on his bum for the last two metres. He came to a stop right next to Harrie and gazed up at her adoringly, as if the whole tangled, embarrassing entrance had been planned.
‘One day he’ll grow into those large paws of his,’ Rachel whispered to Maggie. ‘Hopefully.’
‘Banjo, I have an important question for you,’ Harrie said, solemnly meeting the dog’s gaze.
Banjo barked once. Everyone in the family knew that meant ‘yes’, except when it meant ‘no’.
‘Do you think I should stay up late so I can see the full moon in my telescope?’
Again, Banjo barked just once, and Harrie turned back to her mothers. ‘See?’
‘Well, no arguing with that,’ Rachel said.
Maggie let out a small sigh. ‘All right, but just this once. You are not to take this as permission for you to stay up every time you want to go out and look at the night sky.’
‘Maybe once every twenty-two days?’ Harrie suggested.
‘Don’t push it, kiddo,’ Maggie said. ‘Now go and get some warm clothes on. The last thing we need is for you to freeze out there.’
Harrie grinned at her mothers as she left the table, then hurried to her room, eagerly followed by a scurrying Banjo who this time somehow managed stay upright on all four paws.
#
Although winter was officially over and spring had sprung, Harrie’s home town was high up in the mountains and it got cold there when the sun was down. But it did make for spectacular nights, when the stars and the planets danced across the black velvety sky.
Harrie loved looking up at them even when she didn’t have a telescope, but now that she could see them up close the night sky seemed twice as special. And the most special thing in the whole universe to see with a telescope was the Moon.
The first time she had looked through the eyepiece and the Moon suddenly swung into view it seemed to jump right out at her and she forgot to breathe for a long time, and when she finally did breathe out it came in a great big gush.
The Sea of Tranquility (Creative commons: photographer unknown)
Harrie never got tired of looking at it. She knew all the big craters now – like Copernicus and Kepler – and all the big seas – like the Sea of Nectar and the Sea of Islands. But most especially she knew the Sea of Tranquility, because that is where the first humans who walked on the moon landed their spaceship, called the Lunar Module.
The night was getting colder and colder. But Harrie didn’t feel it. Even Banjo was getting cold, and tried snuggling up against her legs, almost tipping her over. But Harrie didn’t care. Her mothers were softly calling to her to come back inside. But Harrie didn’t hear them. Staring through her telescope at that great white globe with all its craters and seas and mountains was more important than being warm or going to bed.
One day I’ll go there, she thought. One day I’ll go the Sea of Tranquility and touch the dark soil and then look up and see Earth, and with my telescope I’ll find home and wave at my mothers and Banjo and everyone else I know.
Maggie tapped her gently on the shoulder. ‘It’s time, Harrie. We’ve let you stay up for a long while. Come inside now. Your cheeks are as hard and cold as ice.’
Slowly she drew back from the telescope. When she looked up into the sky again the Moon was still there but much smaller.
‘Still pretty,’ she said, ‘no matter how big it is.’
Maggie and Rachel stared up at the Moon as well. Even Banjo, who was wondering what everyone was staring at that seemed so interesting. There wasn’t a rabbit to be seen anywhere.
‘Look!’ Harrie said, pointing at the soft nebula of light that surrounded the Moon. On either side of it was a little light. ‘Are they planets or stars?’
Maggie laughed. ‘I’ve heard of them but never seen them before.’
Rachel and Harrie looked at her expectantly. ‘What are they?’ Harrie asked.
‘They’re called Moon Dogs. It’s so cold up there that the light from the Moon is being caught by ice crystals. They almost look like miniature moons, don’t they?’
Harrie sighed, a deep and immensely satisfying sound. She patted Banjo on the head and started back the house, the moonlight shining in her hair and on his fur.
She stopped for a second, looked back up at the sky, and said, ‘Look Banjo, Moon Dogs.’
Banjo barked once, meaning, ‘Yes, what else would they call them?’
Pluto as seen by New Horizons. Image credit: NASA/JHUAPL/SwRI
AJ and I ducked out of the house on the night of August 11 to have a quick wine or two at King O’Malley’s pub in the city. When we got there we discovered the place had been invaded by Science in the Pub, and the two of us spent a pleasant hour drinking white wine, eating free food, and watching a slide show about the New Horizons mission to Pluto.
What’s more, it was a presentation hosted by John Berry, the American ambassador to Australia, and featured Nobel prize winner Brian Schmidt from the ANU, science communicator and astrophysicist Alan Duffy from Swinburne University of Technology, and Glen Nagle, Education and Outreach Manager at Canberra’s Deep Space Communication Complex at Tidbinbilla.
It was a pretty crowded affair and the screen was sometimes obscured by jostling customers, excited science addicts and through-traffic, but the mood was positive and the atmosphere … well … sciencey. (If this isn’t a word already, I bag naming rights.)
What follows are some of the amazing facts we learned about the New Horizons mission and Pluto, plus a few extra tidbits.
The mission was launched on 19 January 2006, when Pluto was still classified as a planet. Eight months later it was demoted to a dwarf planet. Furthermore, in 2006 only three moons had been identified orbiting Pluto. Before the probe reached its destination, we knew of five moons.
The probe’s closest approach to Pluto occurred nearly nine months after launch, on 14 July 2015, and after a journey of approximately 7.5 billion kilometres. Disappointingly, New Horizons was 7.5 seconds late for its appointment.
Still, not too bad when you consider that to travel the same distance travelling at a highway speed of 100 kph, it would take you around 8,560 years. In other words, to arrive in 2015 you would have had to start driving about the same time the world’s first city walls were being built around Jericho.
Shots of Pluto’s night side were made possible because of reflected sunlight from Pluto’s largest moon, Charon.
Pluto’s atmosphere expands as its eccentric orbit brings it closer to the sun, and then freezes when Pluto recedes from the sun. Since its last closest approach to the sun in the 1990s, Pluto’s atmosphere has halved. This was confirmed by a radio signal sent from Earth to New Horizons through the atmosphere when the probe reached the other side of Pluto. The signal had to hit a piece of equipment about the size of a credit card, and enabled scientists to measure the signal’s radio occultation.
Scientists were surprised to discover that ultraviolet light broke up some of the methane in Pluto’s atmosphere create more complex hydrocarbons such as ethylene and acetylene. They were even more surprised to learn that about 50% of this UV comes not from our sun, but from other stars.
Go here to read up on the background to this spectacular image of Titan, Saturn’s largest moon and the second largest in the solar system. Titan is the only moon in the solar system with a significant atmosphere and surface liquid.
Photo courtesy of NASA/JPL-Caltech/University of Arizona/University of Idaho
Strange Borders 