But be honest, aside from that, what's new?

Our traveller stares out through the double-glazed window which keeps heat in and noise out. The house is toasty warm yet the heating hasn't been on for a while, but the roof and wall insulation is invisible to them. One room over, the cutlery is being cleaned in a dishwasher so quiet our traveller doesn't consciously register that it is running at all. The buttons on the telephone reflect that the exchange has electronic switching instead of human operators plugging in wires, but this is not obvious.

Were it night time, they could marvel at the switching speed and brightness of the LED bulbs. If they stayed longer perhaps a year with no power cuts would interest them. A ride in the car outside would not reveal disk brakes, power assisted steering, crumple zones, fuel injection, catalytic converter or make clear the Interstate Highway routes. Air conditioning they might feel, but GPS and dashboard camera might pass as uninteresting blank boxes. They can't compare the smoothness and quietness of the vehicle, or the reliability of motoring with 1950, or the convenience of calling a breakdown truck when the mechanic has a cellular telephone in the cabin.

Glancing at the clock on the wall, our traveller cannot tell it has a quartz movement and a small battery, and has not needed adjusting or winding in several years. Overhead, radioactive material ionizes air and causes a current between charged plates, but the traveller is unaware of smoke detectors. A device able to cook food using microwave energy is mistaken for a traditional oven and dismissed. The orchestra is still playing in the house, this time not from a radio with a small choice of stations, but from an internet service with several million songs, but the workings are invisible and therefore unnoticed. The speaker came over the Pacific Ocean, for an amount of money that would drop jaws if known, but jaws stay still.

Our traveller does not contract the Polio virus, but thinks nothing of it. They undergo no CAT or MRI scan, experience no painless dentist visit. Nor do they realise they even have DNA which could be tested for anything. Out on the road, a Lithium Ion battery powered vehicle moves past the window, but attracts no attention. Far overhead, a space station orbits, footprints exist on the lunar surface, and a spyplane passes by on the edge of space while travelling faster than the speed of sound. Ordinary invisible impossibilities. Straight through our traveller's head passes digital video signals, from a radio controlled plane; they will be received by a small antennae and then shown to a hobbyist wearing a head-mounted display. At the same time, digital television signals - once passing through an undersea optical fibre - cross the room and move towards a hiking group on a nearby hill, people wearing light yet dry artificial fabrics and carrying an entire tent in a small backpack.

Passing the affordable yet durable Ikea furniture, mistaking it for more expensive items with worse fire resistance, mistaking the DVD and BluRay collection for a bookshelf of glossy-spined texts along the way, our traveller does not order a takeaway, does not explore the wide range of foreign cuisine foods in the freezer, or notice the absence of sewing machine and thread in the cupboards and become curious about the changes to clothing which makes home repair unnecessary. Hot water comes on demand as in 1950, but the lack of water tank makes no difference to the effect.

The clean air act of 1956 makes London air more breathable. The air has no leaded gasoline fumes. For whatever that's worth to our traveller, who is only looking for macro scale changes immediately apparent to a glance from a person from 1890. But not looking very closely, for a desktop calculator, a biro, an absence of logarithm book, few stamps for letters, and spectacles so thin and light with lenses personalised one could hardly believe it, are too subtle for a quick glance to take in. Struck with an idea, they decide to take a look in the workshop - garage, shed, place where tools will be - and there they are, garden tools, same as ever, painted hobby soldiers quietly not made of lead, a soldering iron, and of course a bicycle. But they don't pick it up to notice how light and strong the frame is, or observe the LED lighting as anything noteworthy. A treadmill puzzles them for a moment - they guess what it is, but why is it here? Several things like it, does the house owner run a gymnasium?

What they do see is a wall of bright plastic tubs, one apparently containing a dismembered Christmas tree. They aren't made of wood, or cardboard, and they aren't painted. The material is unusual - were these anywhere in 1950? This isn't a Bakelite telephone, for sure. Inside, small and thin and very very light bags - some coloured, some transparent, a label, "plastic". Suddenly they notice it everywhere they look. That wasn't like 1950. Some things are hanging from the wall by means of a scratchy rope which sticks to itself. Superglue, white-out correctional fluid, WD-40, unfamiliar products to a house of 1950.

Somehow still unimpressed, they walk back past the non-stick cooking items, past the CFC-free energy efficient refrigerator, past the gas cooker which needs no matches to light it, past the Mandelbrot fractal design on a mug, over the Penrose tiling on the floor, noticing the "broken" headphones with their missing wire, unaware of the electronic music they aren't playing. There's no note on the fridge reminding anyone to feed the cat, as a timed food dispenser does that. Instead our traveller recoils at a picture - a coloured woman sitting next to a white man, in a restaurant, both smiling. No sign of argument or police removing her from the premises. She's holding - drinking from? - something bizarre, a cylinder of metal with a ring top. Behind her, two golden arches on the wall. On the table a child playing with a toy vehicle with a skirt instead of wheels.

Puzzled again, the traveller looks around at the sheer amount of stuff in the home, how wealthy are these people?