Historical Events  Science
Historical Events  Science
Rat

Alternate:
Fleas on rats were responsible for the Black Dealth Plague

Current:
Fleas on rats were not responsible for the Black Dealth Plague

The mother of all pandemics

The recent covid-19 global pandemic is  causing serious problems worldwide, but it's nothing compared to the Black Death of the Middle Ages.

The plague swept Eurasia, North Africa and Europe killing up to 200 million people in just 4 years. It's known it was caused by a highly infectious bacteria, and the popular idea of how it spread was via the fleas on rats. Samples from plague victims graves suggest this is the case, since the fleas are still present on the bodies.

However, it's the rats which getting the blame for something they didn't do. In particular, some studies have shown the rate of spread couldn't have been as fast as it was if it were the rats alone. This is because most rats live their entire life around 100 feet from where they were born. They are not natural migratory animals. Also, the sheer number of rats required to cover the areas infected meant there must have been large numbers of dead ones literally everywhere, and there are no reports of these either.

What is known, however, is that the humans of the day had incredibly poor hygiene... 

Historical Events  Science
Goldfish

Alternate:
Goldfish have a 3 second memory

Current:
Goldfish have at least a 6 month memory

Smarter than you think

Most people think goldfish only have a 3 second memory, but the truth is very different.

Science has shown they can remember things for at least 5 months, and are smarter than is generally given credit for at problem solving too. in an experiment, which by the sounds of it anyone can easily repeat, a red Lego block was dropped into the bowl of ordinary pet goldfish just before food was sprinkled on the surface of the water above the block. The fish soon learned the arrival of the block meant food, and swam towards it. Then, feeding resumed normally with no block, only to resume 1 week later. Sure enough, the canny fish swam straight to the block as soon as it was dropped in.

Historical Events  Science
Pythagoras

Alternate:
Pythagoras created The Pythagoras Theorem

Current:
Pythagoras did not create The Pythagoras Theorem

Hypotenuse squared

It sounds like a joke - who invented the Pythagoras theorem?

Certainly, the name popular today comes from the famous ancient Greek mathematician, but of course its the formula itself that's under question.

Most people who studied any level of mathematics at school would have been taught the familiar "square of the hypotenuse is equal to the sum of the squares of the adjacent side of a right angled triangle". Or, perhaps more familiar, a2 + b2 = c2. However, the idea is wasn't known about before Pythagoras cannot be true, since it is referenced in m,any works pre-dating him by many years, and in several different situations too.

Historical Events  Science
Mars

Alternate:
Mars was always thought to have no ice caps

Current:
The ice caps of Mars have always been known about

Water on Mars

The search for life beyond earth has intrigued mankind since humans first gazed up at the stars.

Mars was first properly observed by Galileo in 1610, and from then on better and better observations have been made right up to sending landers to its surface. Along with all this research has been the quest to find evidence of life there, and the assumption that for it to exist, water must too, has been part and parcel of this from the start.

The problem is that it's now being shown that the ice caps have been known about since Galileos discovery, where he documented these and various darker regions, even giving some their names. Yet many hear about the Mars ice caps and think they must be a new discovery, or else they must have clearly been misinformed regarding the presence of water on the planet.

Historical Events  Science
Food pyramid poster

Alternate:
The US Food Pyramid poster was in classrooms from the 1970s onward

Current:
The US Food Pyramid poster was in classrooms from 1992 onward

On the classroom wall

Most Americans are familiar with the Food Pyramid, a graphic showing the optimal number of servings for various food types which appeared in most schools for decades.

The image is actually a standard, and was introduced in 1992 by the US Dept of Agriculture, USDA, and titled the "Food Guide Pyramid".

This comes as quite a surprise to many people who were at school way before that date, but still remember it exactly as seen today.

Historical Events  Science
Ostrich head in sand

Alternate:
Ostriches bury their heads in the sand

Current:
Ostriches don't bury their heads in the sand

Nothing to see here

Are ostriches getting a bad rap?

The general consensus is that when they get scared, they react by sticking their heads in the sand. This idea is very widespread, particularly in cartoons which people see when they are children, and hence get this image reinforced many times whilst they are young.

A moments thought would show this is unlikely, if for no other reason than it would prove an evolutionary disadvantage since predators would quickly latch onto this behaviour and wipe out the entire species.

Sometimes from a distance it might appear an ostrich has it's head in the sand, but it is only reaching down to feed.

Ostriches are not only fast runners, but can actually hold their own in a fight, so the idea they can't handle themselves when stressed is a little wide of the mark.

Historical Events  Science
Covid-19

Alternate:
TV showed panic and people dropping in the streets in Wuhan

Current:
TV did not show panic and people dropping in the streets in Wuhan

Covid-19: TV showed Wuhan mass panic?

2020 was the year of the global lockdowns due to the Covid 19 pandemic, with the sign of everyone wearing a face mask becoming the new normal.

When the outbreak was first reported, it was shown to be from Wuhan with reports of it suspected to have originated in a bat. However, there are also reports that the TV at the time showed much more, with mass panic and people falling in the streets as the army moved in to control the chaos. Whilst there are some reports from this time online, none of the kind people remember seeing are available now. Certainly, as Covid spread throughout the world, its effects, whilst serious, were nothing like as dramatic anywhere else.

Is this a 2020 Mandela Effect, or is something else going on such as censorship after the event?