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Do space and time exist? What is reality made of?
Scientist Carlo Rovelli has spent his whole life exploring these questions and pushing the boundaries of what we know. His Seven Brief Lessons on Physics outsold Fifty Shades of Grey in his native Italy.
In his latest book, Reality Is Not What It Seems, he shows how our understanding of reality has changed throughout centuries, from Democritus to today’s theory of loop quantum gravity. The theory of loop quantum gravity – Rovelli is a leading proponent – suggests a recurrent universe, or a “Big Bounce”.
Here we learn that time is not quite what we might think it is.
THAT THE NATURE of time is different from the common idea which we have of it was already clear over a century ago. Special and general relativity made this explicit. Today, the inadequacy of our common-sense view of time can be easily verified in a laboratory.
Let’s reconsider, for example, the first consequence of general relativity. Take two watches, ensure that they mark exactly the same time, place one on the floor and the other on a piece of furniture. Wait for about half an hour and then bring them back next to each other. Will they still tell the same time?
The answer is no. The watches which we usually wear on our wrists, or have on our mobile phones, are not sufficiently precise to allow us to verify this fact, but in physics laboratories all over the world there are timepieces precise enough to demonstrate the discrepancy which occurs: the watch left on the floor is slow when compared to the one which has been raised above it.
Why? Because time does not pass in the same way everywhere in the world. In some places, it flows more quickly; in others, more slowly. The closer you get to the Earth, where gravity is more intense, the slower time passes. Remember the twins in Chapter 3, who ended up with different ages as a result of having lived one at sea level and one in the mountains?
The effect is very slight: the time gained during a life spent by the sea, with respect to one passed in the mountains, consists of fractions of a second – but the smallness of the amount does not alter the fact that there is a real difference. Time does not work as we customarily imagine it does.
We must not think of time as if there were a great cosmic clock that marks the life of the universe. We have known for more than a century that we must think of time instead as a localised phenomenon: every object in the universe has its own time running, at a pace determined by the local gravitational field.
But even this notion of a localised time no longer works when we take the quantum nature of the gravitational field into account. Quantum events are no longer ordered by the passage of time at the Planck scale. Time, in a sense, ceases to exist.
What does it mean to say that time does not exist? First, the absence of the variable time from the fundamental equations does not imply that everything is immobile and that change does not happen. On the contrary, it means that change is ubiquitous. Only: elementary processes cannot be ordered along a common succession of instants.
At the extremely small scale of the quanta of space, the dance of nature does not develop to the rhythm kept by the baton of a single orchestral conductor: every process dances independently with its neighbours, following its own rhythm.
The passing of time is intrinsic to the world, it is born of the world itself, out of the relations between quantum events which are the world and which themselves generate their own time. In fact, the nonexistence of time does not mean anything particularly complicated.
Carlo Rovelli is a physicist and bestselling author. Reality Is Not What It Seems is published June 2017 by Penguin.
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No border ever ……….its our island ….
Stand up and be counted….
@Aiden Galvin: I’m standing up. What happens now?
@Honeybadger197: sit down lad i cant see
@Aiden Galvin: It was your idea man!
@Honeybadger197: i know i know but your taller then i expected
@Honeybadger197: just waiting on some Gardai to come and count.
@Aiden Galvin: you and honey are hilarious I vote the pair of you decide on 3 options and we vote on the one we like best? Good poll for a change.
@Father Hody Commody: can they?
@Aiden Galvin: Leo’s unique is sounding very like Sinn Fein’s year old special status calls. Bit late but at least he is trying to catch up.
“the issue of the border continues to be a vexing one, but says that a solution is needed”
We’re spending €5 million a year so he can be Captain obvious and come out with that kind of sentence!
The division between north and south post-brexit will be an EU land frontier. So long as the UK also departs from the customs union, then the border will be a trade border.
This affects not only consumers who will have limits (300 EUR a day or whatever, much like as at the airport, and as it used to be) but also companies who must declare their imports and exports for customs tariffs, VAT refunds and regulatory inspection.
There is scope for free movement of people, as is the case in the Schengen area. Several non-EU countries are part of the Schengen and can move across borders without passport or ID controls, but the goods remain tax and duty liable.
I lived some years in the south of Germany close to the Swiss border, also an EU frontier. Thanks to Schengen, people can move. Goods cannot. It’s awkward, restrictive but it’s the way it has to work.
Bandying this word “unique” around just tries to glorify the position.
There’s no way in hell the Brits would join Schengen, or anything similar.
@Pied Piper: we have a common travel area that existed long before the EU came about and this has to be maintained…..schengen isn’t needed
@Pied Piper: Well said and I might add that it is probably “one bottle and 200 cigs” that you are allowed – no more Christmas drinks shopping allowed under current EU rules,, and what about the trade in bringing in second hand cars from the UK? Will they require customs and VAT be paid as well as VRT – same rule as shipping second hand cars from Japan?
On another front, the shops in Paris will not want the free movement of goods between Ireland and Paris if we also have the free movement of non duty paid goods from Northern Ireland.
Do people remember when you could not even bring in a pound of butter? The EU have rules about employees conditions and item production etc., that are enforced within the EU to put all competitors on a equal footing, the Northern Ireland exit could give unfair advantage to the UK to use “cheap” labour to produce cheaper “inferior” goods as they would no longer be compelled to comply with EU rules and the EU would have to impose restrictions which cannot be implemented without some sort of stopping and checking the contents of vehicles and items carried by travellers travelling to and from the EU.
This “we will not help develop a solution” attitude is really saying that there is no “unique” solution to the problem or put another way “I do not know how to fix it but… if I keep my mouth shut then I can blame someone else”.
Ireland still have passport controls to other EU countries so we can retain the free movement people between Ireland and the UK – and that is easy cause we will not have a land border with other UK states – and this could permit the re-introduction of pre EU membership controls (checks) being introduced on good entering the EU from Ireland if we do not step up to the plate and implement controls on good entering Ireland – not that would be a “unique” solution which, in a nut shell means that if the the UK does nothing the ball will end in our court to do the impossible.
@Cathal and @diarmaid I know, I wasn’t suggesting that as I know hell would first have to form a thin layer of ice on its surface. I was saying that travel arrangements can exist beyond the EU membership. Iceland is another example.
The only end result I can see is a customs border, with free movement of people. Any freedom of goods into Ireland would mean the loss of import duties and VAT a) for Ireland and b) for all other EU countries whose companies would use Ireland as a channel in and out of the UK – there’s no way the governments of those countries would have that – and the EU being the EU, these governments will all get their say on moving forward – Ireland isn’t negotiating for itself here.
Timeline, FF making the most of the whole weekend of publicity with their Ard fheis, spewing out bs on everything they can think of from SF to scientology. FG 5 million euro PR unit says we can’t have that, we must think of something to say, quick, so leo’s got a unique brexit border solution, well what is it? They say, we’ll tell you some other day!
Leo Varadkar solves the “Irish Question “can’t wait to hear this solution
Brexit will never happen. I wonder how all these officials occupied their time before there was any mention of Brexit!
Well given that Verhofstadt called the border an illogical absurdity (an Belgians know all about surrealism) a border that goes through Mrs.Murphy’s kitchen outside Clones can not clearly be the external border of the single market…unless they want it wide open to the birdies. So Varadkar is just stating the bleeding obvious. There will be a special arrangement for Ireland as a whole and that is that.
@John Sullivan: plus the whole preexisting common travel area we have with the uk which predates the EU needs to be recognised too.
Amusing to see the cynical eurocrats using the internationally recognised border as another stick with which to beat the British on Brexit – as if they cared.
Just to bring matters back to reality. If Brexit does in fact happen. There won’t be anything special about Ireland. There will be a border. There will be border control. Varadker has neither the age or experience to say anything else. The civil service are the people who know. Varadker can spout idiotic soundbites all he likes, but he hasn’t a clue.
@Father Hody Commody: Very true but it will be the Belfast gombeens controlling it, not Varadkar….
Can we cut Northern Ireland out and push it towards Scotland?
Unique? Great big wall?
Very simple answer to the border. “get out brits”
An Irish solution to an EU problem, we will simply operate the notional border on a purely notional basis, repeat notional not national.
As long as the British pay for the border systems & infrastructure outlined on whatever map, avoid putting anything in place to shoot at, make sure the British & Irish paperwork, & import export tables tally( nice job for redundant Brussels staff), sure everyone will be able to carry on regardless. Carry on Regardless, a British comedy,& an apt motto for the Irish version of Brexit.
The practical reality is that the only effective way to monitor the movement of goods & people is at the UK arrival points, if they really want to do it.
I love the buzz words “ relationship is fragile “
Meaning : oh sheeeeeit is gonna go down!!
At least Varadkar has finally said something sensible it, eventhough we don’t want a border he shouldn’t leave it all up to the British god knows what feckin mess they’d make of it – I just hope the EU gives them such a big divorce bill for Ireland that thy finally decide to up sticks and leave permanently.
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