# Would common people in central Europe in the 15th century notice that the whole Asia disappeared?

We have earth at the beginning of the 15th century, and suddenly the biggest continent disappears. There is nothing left of it, no animals, people, lands, anything.

I don't think the details of the reason to disappear is essential. I want to add that there are no noticeable catastrophes connected with the disappearance itself (there is not mega-tsunami or anything like that). But of course, any effect that the absence has on the climate and environment would follow.

I understand that some people would find out, but I don't see a reason why they would share this information with common citizens. Also, I am curious about how long it would take.

By central Europe, I mean approximately the same area where the Czech Republic is located.

By common people, I mean those who weren't in a position that would make them exceptionally informed about such things (for example, in the government, very well educated scholars, travelers, etc.). I imagine some farmer who lives his whole life with his family in the village and travels only to the nearest cities.

By knowing I mean that they know that part of land far in the east is not there anymore. And they have at least a vague idea of its size and location.

By Asia I mean the part of Euroasia east to the Ural mountains and Ural river. The Arabian peninsula, Anatolia, and the Levant also disappear.

By disappearing I mean that all the lands with everything on them are just gone. There is only an ocean now.

So:

Would common people in central Europe in the 15th century have noticed that the whole Asia disappeared? Would this message get to them?

If so, how long would it take?

• Also, what do you mean by disappeared? Like all the land there disappeared or just every individual alive? – cyber101 Jan 30 at 18:26
• I already answered, but then realized one other clarification is needed. Does the Arabian peninsula, Anatolia, and the Levant disappear? Those are part of Asia, but your Ural Mountain border doesn't help much with them. – tbrookside Jan 30 at 18:53
• @TGar - OK now that REALLY changes things. The Mediterranean is now part of the Pacific Ocean! – tbrookside Jan 30 at 19:12
• Climate change would be rather noticeable. Those harsh continental winters? They will be gone. Also, I don't know about the Bohemians and the Moravians, but the Romanians will immediately notice that their neighbors across the Black Sea, Circassia and Georgia and Armenia, are gone, and that their friends the Turks have suddenly lost their high and mighty demeanor... The Romanians will tell the Poles and the Hungarians, and the Hungarians will tell the Bohemians. – AlexP Jan 30 at 19:34
• How deep into the earth does the disappearance go? This is pertinent, because it determines the amount of new coastal land and the size of the tsunami created when the oceans pour into where Asia was. And, @user28434, people in France, as well as Central Europe, would certainly notice these things. – WGroleau Jan 31 at 17:16

People would notice it, but they wouldn't necessarily know what happened

I'm going to assume you meant that all of the land that makes up Asia just disappeared one day. To answer your question directly at first:

1. Europe is connected to Asia: so people at the arbitrary edge at which point Europe turns into Asia would disappear.
2. Traders would know - and traders gossip: Entire trade routes would fall apart - no more silk road! People often underestimate how connected the world was back in the good old days. Sure, no one knows about Chinese court politics, but everyone knows where silk is from. Speaking of which, international traders would immediately go bankrupt as their primary source of exotic goods just disappeared. So congrats, the single biggest source of luxury goods in Europe disappeared with all of its people too. All coastal/trading towns would find out about all of this (initially in disbelief) and freak out.

Now for the less intuitive stuff - climate and environment:

1. Sea levels dropping significantly: Asia is the largest continent on the planet - 9% of the world's surface area, or 36% of all actual land. So suddenly this is all ocean. The Indian and Pacific Oceans would have to immediately re-adjust themselves to fill up the massive void left by this disappearance, with the Atlantic, Arctic, and Antarctic oceans following suit after. By the Ural river definition, suddenly this river is a ocean coastline. Bringing me to my second point.
2. TSUNAMIS!!: Not accurate but hear me out. In order for the above water displacement to occur, it won't necessarily be a smooth process - all the ocean water in the world will slam into the the banks of the Ural river. Such effects will be less significant in let's say the coast of Spain. On the opposite side of things, the Native Americans in California will be pretty confused to see their coastlines increase randomly - as will everyone else later on.
3. Climate change: The largest chunk of land on our planet just disappeared - this is bound to have long-term consequences. I have no idea what these could be, but they'll probably be pretty massive. For one thing, the western half of Russia will have a beach now - not something anyone expected. This will mess with weather patterns for whatever is left of the world.

So yeah, changes would be pretty significant. Now what can anyone do about this? Up to you and your story tbh. My estimation is that (other than completely reclusive societies), pretty much everyone will notice something going wrong within a year. They may not know/understand the scale of what just happened, but within a year they will have seen the first climate effects of this disappearance. As word spreads, all of Europe will know that something crazy just happened. I'd assume that word would spread across Africa too (maybe not the Congo, but definitely the West African nations). The Native Americans on the west coast of North America would also notice - as would the Incans and Mesoamerican civilizations - but Iroquois would likely not notice immediately. Assuming that the Americas haven't been discovered, no one in the New World would know what happened.

• How 1 and 2 would change depends on the post-event bathymetry, which the OP didn't specify. – gerrit Jan 31 at 12:11
• I agree - but I assumed only the land disappeared (wasn't replaced by an equivalent mass of ocean). If the OP would like to clarify that would be great, and I would change my answer accordingly. – cyber101 Jan 31 at 15:14
• I also find the idea of the ocean starting at the top of the mountain range quite amusing. The view from Gora Narodnaya must be veeery vertiginous :) – gerrit Jan 31 at 15:25

## Word of mouth says: "An act of God"

People living in France wouldn't see direct evidence of Asia disappearing - but they would hear about it soon enough! Eastern Europeans would see direct evidence of the land next to their houses disappearing. Such a catastrophe would immediately spread across the continent through word of mouth because of its religious implications. It would be considered an act of God, and the Catholic Church would be forced to interpret and report on its meaning. Your average European may not be educated or informed, but if all of Asia disappeared, that would be a big deal.

## Climate Change is Noticeable

Depending on how deeply you uproot the Eurasian continent, you'll see a lot of water flowing into the resulting cavity. Even if you don't want any natural disasters (which such a large flow of water would inevitably cause), imagine sea level all along the coast of Europe sinking permanently, presumably by several feet.

On top of that, water moderates climate. Whereas Eastern Europe once had hot summers and cool winters, it will experience a moderate climate with little seasonal variation - and potentially lots of precipitation.

• I assumed that Asia would be replaced by ocean water where ocean water should be, rather than air. – John Dvorak Jan 30 at 19:28
• An ocean where Asia was would also change the climate noticably. – Slarty Jan 30 at 20:37
• +1. If Jerusalem and all holy cites don't exist anymore, that would be a huge news for Europe. – Alexander Jan 31 at 0:14
• Don't forget that almost half of the Ottoman Empire has also disappeared (1450AD, Anatolia is about half of the Ottoman Empire). The news would spread like wildfire... – John Hamilton Jan 31 at 7:36
• @MatthieuM. well, at the beginning of 15th century nobody in the old world had any potatoes, they only arrived in the late 16th century. – Peteris Jan 31 at 12:47

Common folk in 15th century Europe surely would notice if Asia vanished, though it might take a while.

How?

They'd notice that their "betters", the wealthy and the nobility, quit having new silk garments made (because there was no new silk to make them from).

Servants in the mansions and palaces would notice first, then the word would pass from them to the other commoners (via marketplace gossip, casual mention to relatives, and so forth). Eventually, there would be an increase in plantings of linen and hemp, imports of cotton from Egypt and possibly planting of cotton in southern Italy or Greece, Lebanon, Syria, and so forth (some of Turkey has the right climate, but it's technically in Asia by the old borders).

Ethiopians and Arabs were drinking coffee by this time, and without tea to begin importing along the Silk Road, coffee might tend to invade Europe a couple centuries earlier than it did in our history, because everything in life is better with caffeine.

Those who make a livelihood from mining and trading amber would find most of their market dried up, because the caravans that once carried amber as part of they trade goods against silk stopped.

There would likely be a large number of smaller effects, but these are the most immediately noticeable: the ones that have a large effect on expensive goods.

In the end, it might take as long as ten years before the reason for the change was known, when silk/amber caravans started to return with the same goods they'd left with, to report that they'd come unexpectedly to untraveled sea east of, say, Persia (or Turkey, or wherever the actual break occurred). As noted in comments, however, depending exactly where the break actually occurs, the Holy Land (on the Mediterranean side of the Arabian peninsula) vanishing would result in notice reaching France and England as rapidly as people could travel to make the trip from the Bosporus -- possibly as little as a few weeks.

• Point of order: This answer doesn't address the "knowing" criteria defined in the post. The common people would know that trade stopped. They would have no way of knowing it was because Asia wasn't there anymore. Not that they would really care, for that matter. – Morris The Cat Jan 30 at 18:39
• They'd know a whole lot faster and more directly than that. The disappearance of the Holy Land would be huge news. I'd guess it to be "as long as it takes someone on a fast horse to get there from Istanbul". – Mark Jan 31 at 3:18
• I'm not convinced that wealthy persons would "stop" wearing silk. That fabric is durable and lasts for decades; they would continue wearing the garments they already had. Also, any change in the clothing of the wealthy might easily be dismissed as another fashion fad. – DrSheldon Jan 31 at 5:44
• Rumours would start spreading with the return of the first caravan that had to turn around because the was a coast where there was land before. So the first sign would not be lack of tea and silk, but rumours. – toolforger Jan 31 at 8:20
• @JamesKhoury Sleep is for when you don't have enough caffeine, isn't it? – Zeiss Ikon Feb 3 at 12:04

Yes

The 15th century Europeans had two qualities which would ensure that everyone knew about this. The first is that they knew that Asia existed, and regularly traded with it. The second quality is that they had quite a powerful religious organization in the Church.

This is how I see the timeline: Asia disappears. A few weeks or months pass, and a traveling merchant band shows up to traverse the Silk Road, only now it ends in a vast ocean. They find this odd, and check around to see if this was some kind of a freak inland sea, but nope, it's water as far as the eye can see. They head back and when the irate nobility is asking for their silk, they explain that China disappeared, what could they expect?

Now, the nobility don't believe them, but when every merchant shows up saying the exact same thing, some king of some country (Spain and Portugal are likely candidates at this point) sends an expedition, and wouldn't you know it, but the area which was formerly China is now an ocean. This isn't going to happen overnight, maybe it'll even take upwards of fifty to eighty years, but this will happen. And that's when the Church gets involved. They can't not know about this with the power they had at the time and a massive chunk of landmass turning into ocean has only one conceivable explanation - it's an Act of God.

At which point the tale of how this far-off land full of heathenous non-believers got wiped off the map via divine retribution gets added to the Church's repertoire of stories, and thus all the common people in Europe would find out.

• a traveling merchant band shows up to traverse the Silk Road, only now it ends in a vast ocean — merchants usually haven't "traversed" the Silk Road, they just traveled back and forth between "trade posts" on the Silk Road buying and selling goods. Only goods were going all the way through, not the people. Well, except Marco Polo, but he was a weird fellow, and is known exactly for going all the way to the China and back. – user28434 Jan 31 at 12:14

This is kind of a mixed ball of stuff here.

As for the hypothetical village, peoples in villages didn't get around much. It's sort of accepted that the bulk of the population in a village was pretty stationary, with folks living their entire lives never travelling much more than 30 km from where they were born.

Yes, there are traders, nomadic people like the Romani, and the occasional story hero running away to seek fame, glory, and wealth. These would of course be the first to know that some sort of disaster happened to the east. Depending on where your village is, exactly, They will probably know of something within months of it happening.

Here is the thing. If they know, do they care? A typical villager is not going to be worried about goods coming along the silk road. They want to know if they are going to have an adequate harvest. They care that the cow is giving milk. If the local lord gets cranky because he can't buy silks and spices, that could cause an impact on the local village, but that's about it.

Of greater importance would be changes to local weather. I'm no climatologists, but the local climate will be impacted in one way or another. That said, the local peasants are not going to be able to connect the disaster in Asia to why they are getting warmer weather and more rain.

So, yeah, they will know something big happened, but they probably won't care because it happened more than 30 km away. To them, that may as well as be on the other side of the planet.

• Actually medieval people were quite mobile; they did pilgrimages, to places as far away as the westernmost part of Spain (St Jacob's pilgrimage) and Jerusalem. Actually a year of travelling and learning abroad was mandatory for any craftsman. -- Not everybody would do this, but everybody would know somebody who did. – toolforger Jan 31 at 8:22
• @toolforger The Journeyman system (I think you refer to that) didn't mandate going abroad AT ALL. It just meant that a apprentice, before becoming a master, had to work under at least 1 other master than his original teacher. This could be close to home, even the house next door. Journeymen could and would travel to nearby towns/cities, but most didn't get much further than that. Going abroad was NOT mandatory. – Tonny Jan 31 at 11:45
• I think they'd care, even if the weather didn't change. Traders would spread word that vast kingdoms far to the East had all sunk beneath the waves. This would probably be taken by European Christians as a sign that the world was about to end. – user3153372 Jan 31 at 15:43
• @user3153372 possibly, but then again an inadequate harvest, sour milk, unlikely flocks of birds and other such signs were also signs that the world was going to end. It depended far more on how hysterical the village clergyman was. Remember this is a response to news that is not verifiable to the bulk of the commoners as it required long distance travel. That part of the world is in the same place as "Here be Dragons" labels on the maps. It's so far away as to not be real. – Paul TIKI Jan 31 at 17:41

Bringing the Pacific Ocean all the way to the Urals would have a profound impact on travel and geopolitics even if there were no associated weather changes.

The central European powers might consider the states of India, Bactria, Central Asia, and the far East irrelevant, but the powers immediately bordering central Europe would not. Poland-Lithuania and the Ottoman Empire effectively now have no strategic threat to their rear - but they also have no Asian-facing trade.

The Europe / Arabia / Africa landmass that remains is also now circumnavigable.

The common people might not notice any change in their day to day lives at first, but if suddenly the Ottomans drive on Czech territory, or if following the Reconquista the Portuguese and the Spanish are suddenly sailing on the Pacific coastline of Russia, they might eventually get caught up in the wars that will result as the new power situation moves towards equilibrium.

Edited in response to OP's clarification that Anatolia and Arabia are also gone:

The Ottomans are gone; Mecca and Medina are gone. Islam is destroyed, effectively. The Italians have direct access to the East African coast. The Black Sea and Mediterranean are both now part of the Pacific Ocean. The Dnieper empties into the Pacific! The European powers basically now rumble for dominance of what amounts to "the world".

• Asia having disappeared, what Ottomans are you speaking about? Most of the population of the empire and most of its wealth were in Asia. (And there was no "Czech" territory in the 15th century. Bohemian, yes, Moravian, yes, but "Czech", nope. – AlexP Jan 30 at 19:29
• @AlexP OP originally did not specify that Anatolia was gone. He indicated that everything east of the Urals was gone. Anatolia and the Levant got wiped out in response to my request for clarification above. That led me to revise my original answer. And OP asked what people in the area of the modern Czech republic would notice, so I referred to that territory in my answer. – tbrookside Jan 30 at 19:52

### Yes, they would notice

They would notice within a couple months at least, a few decades at most, depending on the exact part of the century.

The 15th century was when the printing press was invented, and it spread fast.

Also in the 15th century the Portuguese developed caravels and one dude called Vasco da Gama made an amazing discovery: they could sail from Lisbon to Calicut in a little less than a year, by passing through the Cape of Good Hope in Africa.

The round trip from Portugal to India by ocean was just a few weeks longer than a round trip from, say, Rome to India by horse. But when you have boats instead of carts, you can bring one or two orders of magnitude more goods back to sell to your european homies. Portugal instantly became a trade power, and in a parallel universe their national anthem would go "They see me sailin', hey hatin'...". Notice that the portuguese were not the only ones trying to pull this off. Columbus found the Americas while trying to one-up Vasco, so you already had people in the oceans searching for new routes to Asia.

Granted, those voyages were all near the end of the century. Vasco reached India in 1498, the same year when Columbus thought he had reached India.

So if your story is happening on the beginning of the century, it will take time. But if it's end of century, you'll have a lot of western Europe navigators scratching their heads and asking "what the fornication?". In a couple months books detailing such sorcery would have reached the centralmost parts of Europe.

By the way, this is a hunch... But I think people around the areas closer to the vanishing Asia would desperately run west and spread the news. If I were a 15th century peasant and the land before my eyes became sea, I would think it would be an announcement of Gog and Magog coming to end the world. I would surely make my way to holy Rome as fast as I could. And while one swallow alone doesn't make a summer, if you have a massive immigration like that central europeans are bound to take notice.

• But when you have boats instead of carts, you can bring one or two orders of magnitude more goods back to sell to your european homies. — also, you wouldn't need to deal with Ottomans in the Middle East(which you will have to pass on the way there) and their taxes and tariffs. – user28434 Jan 31 at 12:18
• @user28434 you have to deal with storms, piracy and vitamin C deficit instead. Not a great deal if it wasn't for 100x the profit. – fraxinus Jan 31 at 15:00
• @fraxinus, you can get bad weather, robbers and illnesses of all kinds while walking on land too. – user28434 Jan 31 at 15:47
• @user28434 yeah but fraxinus's got a point. Bad weather at sea is much more dangerous than on land. Also you don't get hurricanes on the bulk of continental Europe AFAIK. Last but not least, those guys didn't know what they would find - I think half of Magellan's crew (post South America) died of starvation on the Pacific because there was no food to fin anywhere. – The Square-Cube Law Jan 31 at 15:49

Most common people in central Europe in the 15th century wouldn't be likely to notice for quite a while if EVERYTHING more than a hundred miles from where they were born vanished.

The only people who would be likely to notice your proposed scenario would be people directly involved in the Silk Road trade, and even they wouldn't be able to easily tell the difference between "Everybody in Asia disappeared" and "Bandits in Afghanistan are killing everybody who tries to travel through there."

• I strongly disagree that such a large-scale change would go unnoticed. While not everyone in Europe trades with Asia, everyone experiences its climate impacts. – Zxyrra Jan 30 at 18:43
• @Zxyrra the question specifies "common people" knowing that land isn't there anymore. Would they notice something was different? Yeah probably. Would they have any way to connect "The weather is different" to "The pacific ocean is a couple thousand miles closer now"? I don't see how. Europe experienced MASSIVE climatic impacts from the Tambora eruption in the 19th century, but your average European had no idea what caused it, or where. – Morris The Cat Jan 30 at 18:47
• If Central Europe gets monsoons, that wouldn't go unnoticed. – Alexander Jan 31 at 0:10
• @MorrisTheCat: Sure, the climate would change (the Himalayas direct the jet stream), but no person from that era would attribute such a change to geography. – DrSheldon Jan 31 at 5:50
• They would quickly notice scarcity of metals. Perhaps in just a month or so. Not only gold and silver, but iron too, were usually mined and traded farther than 100 miles. – Juraj Feb 6 at 12:50

# Yes, everyone on earth would notice it

If the whole land mass of Asia suddenly disappeared then this would soon be very noticeable because of the extreme wind speeds as air and water from the rest of the planet fills up the void. Cities within a hundred kilometers from the Asian border would be blown away, a large part of the world population would be killed within minutes or hours, and central Europe would have some serious storm going on for weeks after.

It would take some time before anybody still alive could tell what happened, but they would definitely notice that something happened.

Actually, this might well be a Everyone Dies(tm) scenario...

• I was searching for this answer... Note also that the world ocean level would substantially drop. – RonJohn Jan 31 at 17:57
• Yes, tm by Dave Consiglio. – Peter Mortensen Feb 1 at 10:23

They would know something was wrong, but not what it was for a little while

Climactic Effects:

Asia is the largest landmass on earth, and thus it’s massive size has a considerable effect on the climate due to how much heat is reflected by land compared to water. Magically removing Asia would mean that the waters of the Pacific and Indian Oceans would suddenly border the Urals, which would then lead to massive warm and wet oceanic conditions flowing into Eastern Europe rather than the cold and dry continental climate. The Czech farmers could get hit with massive rain or snow storms depending on the time of year and the exact changes in wind, which could easily lead to crop failures. A failed crop is a major reason to either leave or seek help, which would cause them to learn the truth given time.

Sea Level Drop:

Asia is again a lot of land, and if it is suddenly gone then all of the water around it is going to flow into the continent sized hole. This would lead to perhaps the largest drop in sea levels to ever occur, which would lead to a collapse of ocean ecosystems and fisheries, and would force formerly coastal people to move. Many people would move inland to a more familiar world, and they’d even end up in Czechia given how it wouldn’t take long for refugees to make the trek.

As people move, so does information

### Don't forget the Ottoman Empire

Most answers focus on the Far East. However, the Ottoman Empire was a big player in European politics, having conquered vast territories in the South-East of Europe and was in the process of pushing onward.

The question is based on late medieval Bohemia. Which was directly bordering Hungary. Which in turn was directly bordering the Ottoman Empire, being in near-constant warfare. So the disappearance of the majority of one of the biggest superpowers in the area (and a possible collapse of the rest of it) would certainly be felt in Hungary, and Bohemia is right next door.

How would simple peasants notice? The vast majority of the armies back then consisted of peasants forming a fighting group leaded by their lords in the summer, then returning to their fields for harvest when the fighting season ended. I wouldn't be surprised if many Bohemians took part in Hungarian-Ottoman wars, either as mercenaries or as allies. Especially as Bohemia and Hungary shared a ruling dynasty for some time in the 15th century.

Huricanes / typhoons.

These things are unknown in Europe because Europe has Asia to the east and the tropical cyclons generally start over the water and move to the west. Now Europe has rather large ocean (pacific + what was Asia) and all the circular atmospheric phenomena, probably even stronger than in east Asia, because they have more ocean to grow in. These things are Noticeable.

So your question poses the situation of the world as it was in the 15th Century, plodding along, until in the blink of an eye, everything east of the Urals, the eastern shore of the Mediterranean, Black and Red Seas, and north of the Indian Ocean, is - poof - just gone. No land, no animals, no people, just a massive hole down to bedrock where Russia, China, Mongolia, India, the Arab world and Southeast Asia used to be.

First and foremost, the Egyptians, Greeks, Macedonians and southern Slavs are going to notice almost immediately that the land on the other size of the Gulf of Suez, the eastern Mediterranean, the Aegean and the Black Seas is gone, taking with it many of these cultures' close allies and deadly enemies. Egypt, by the 15th Century, was part of the Ottoman Empire which was very near its peak territorial claim, including most of the Islamic world west of Persia, as well as Greece, Bulgaria, Serbia, Crimea and a few other strongholds on the northern side of the Med in Europe. These settlements would find themselves suddenly and irreversibly cut off from their power center in modern-day northeast Turkey. North Africa by this time was largely settled by Suuni Arabs, who would also have lost their homeland in the Arabian Peninsula (including the holy shrines of Mecca and Medina). That would be offset, probably with very little celebration, of an end to the Sunni-Shi'ite divide that had made the Persians sworn deadly enemies of just about every other Muslim in the known world for nearly 500 years. The Greeks, already living under fairly brutal Turkish occupation at this time, would be looking across what used to be the Dardanelles, expecting to see modern-day Turkey including the other half of Constantinople, and instead, there's a massive hole in the earth filling with the Mediterranean and Black Seas (we'll get to that). So, geographically close civilizations to the borders of what we call Asia are going to see a difference pretty much immediately, and the most immediate effects would turn the Balkans and what's left of the Muslim world completely upside down.

Secondly, and somewhat less immediately but ultimately much more critically, if Asia's really just gone, the rest of the world is going to notice an immediate and very severe drop in sea level. How much? Depends on how deep this new ocean is.

As a very simple estimate, what geographers consider Asia proper, which includes the Arabian Peninsula, Turkey, the Levant and everything east of the Black Sea, is approximately 17.1 million square miles. The total surface area of all saltwater oceans and seas is about 139.4 million square miles. So by literally wiping Asia off the face of the Earth, you've increased the oceans' surface area by about 12% (yeah, only that much, from the world's largest continent; the oceans are big). Flip the fraction, and the world's oceans are about 8 times more surface area of the world than Asia.

So, if we have some fun with this, and posit that whomever or whatever removed Asia in the blink of an eye didn't think to replace the continent's subsurface volume with seawater, then by that same token, for every 8 feet deep your soon-to-be Asian Ocean is, the world's oceans get a foot lower. The average depth of the world's oceans is about 12,000 feet, so if we assume that the Asian continent is removed to that depth below sea level, the water required from the rest of the world's oceans would lower global sea levels by a whopping 1,500 feet.

In reality, it would be quite a bit more than that, because we're only thinking about the portion of the Asian continent that is above sea level now. If we also include the continental shelf region, which would include the relatively shallow South China Sea and shallow areas of the Indian, Pacific and Arctic Ocean, that's a lot more cubic miles of volume removed from the Eurasian Plate (and other smaller ones like the Yangtsze, Amur, Sunda, Indian and Arabian Plates) which would lower the ocean that much more. You could very easily drop global sea levels by half a mile or more.

This would be extremely noticeable to Middle Age Europe. Within a few hours of Asia's disappearance, one could walk from Calais to Portsmouth across what used to be the English Channel, making the British Isles a permanently-connected part of Norman territory. Within a couple of days, you could walk from Tunisia to Sicily and then to Italy without getting your feet wet, and a few more hours after sunrise, you could do the same across Corsica and Sardinia after the last little bit of deeper water drains. The Med is deceptively deep in places, 17,000' at its deepest in the Ionian Sea between Sicily and Greece, but quite a bit of it would be firm dry land within a week.

Further north, the Baltic Sea dividing continental Europe from Scandinavia is only 1,500' deep, and much shallower at the mouth of the sea between the Jutland and present-day Sweden. It's unlikely the Baltic would fully drain for this reason, as the northern Baltic deepens significantly, but it would be an inland salt sea, much like the deeper areas of the Mediterranean.

Randall Monroe did a What If on the topic of draining the ocean that would probably be of use. Let's see... Yes, here we are. Here's what the world would look like if the oceans were 500 meters lower (a little more than 1600', in the lower range of our predicted ocean level drop):

... and here's the world after a 1km drop in ocean levels (about 3200', the upper end of a back-of-the-envelope estimate for lost crust volume replaced by water):

(Source: Drain The Oceans - XKCD What If)

Basically, take these maps, and erase Asia.

The Nordic people would see massive gains in land area, offset by the fact that their fjords are dry. The British Isles would have stopped being islands 400m of drainage ago, and they, along with a lot of currently-underwater shelf to the south of the Channel, would be under a renewed Norman invasion (the British Fleet's defeat of the Spanish Armada wouldn't make the Brits a dominant world power for another 150 years or so).

The draining of the seas would happen pretty fast, as there would be a ridiculously large area of former Asian shoreline for the seas to drain into. I'd expect seafaring vessels in the Mediterranean and northern Scandinavia to be in for quite a ride east, one they very well may not survive. We are talking about a hole 12,000 feet deep where Asia used to be, after all, so sea floors above that level around the former Asian continent would turn into mile-high waterfalls.

Another slightly interesting thing will happen within hours of the continent's disappearance; as inrushing water, converging on all sides, meets in the middle of the former continent. As if a massive drain in ocean levels weren't enough, within a few hours, the leading edge of each bordering ocean or sea will collide in a fantastic fountain of seawater. A few hours after that, any coastal towns unlucky enough to have villagers exploring the dozens of miles of new beach created will get to experience a tidal wave of the backwash from this mid-sea collision, as the fountain settles back down to (rapidly-decreasing) sea level. So on top of the roughly billion people you just disappeared on the continent itself, add in another few thousand over-curious villagers washed into oblivion by the aftermath.

When everything calms down, there will be some lasting effects far beyond the creation of new land bridges in Europe and Australasia. Without Asia and the Middle East, Europe would not have picked itself back up out of the Dark Ages that consumed most of the first millenium AD and quite a bit of the second. To be fair, most of the developments borrowed from the Far East were a few centuries old in Europe by the Renaissance, however Renaissance Europe continued to benefit from trade and diplomacy with the Ottomans and points east through the Reformation years. It's very likely that this massive disruption in the world order could plunge Europe right back into the Dark Ages, as long-distance trade collapses (all the port cities now being several miles inland, and not all the water routes replace by land bridges), making the Renaissance a dim spot of light in what could end up being more than a millenium of stagnation of human progress in science and technology.

The New World wouldn't be colonized by the Spanish, as Spain's naval might would likely collapse fairly quickly in the 1400s with the loss of its existing ports after the Great Asian Disappearance, far earlier than the defeat of Philip's Spanish Armada by the British in 1588. The British would have some trouble too; no longer isolated by the English Channel and with most Southern English ports now landlocked, we'd very likely see the French and Germans both steamrolling the Brits in competing bids to control the newly-appeared land. The Nordic peoples would be in slightly better shape, especially Norway; their port facilities would be stranded high up in the mountains, but the Scandinavian fjords are natural deepwater ports. The Swedes' and Finns' ports are cut off from the North Sea and Atlantic by the new Jutland Land Bridge, but the Norwegians would be among the least affected, still able to travel to Greenland, Iceland and Nova Scotia. With English and Spanish exploration stymied, we really could be celebrating Eriksson Day instead of Columbus Day, as the Nordic explorers would have an extra hundred years or more to colonize present-day New England and Virginia. As long as they made a lasting peace with the Native Americans, and avoided smallpox (never endemic in Scandinavia, so Native Americans north of the Rio Grande weren't fully exposed to it until English colonization in the 17th Century), it's very likely continental Europeans would never take hold in the New World, and a combination of Native Americans and Nordic settlers would dominate modern-day North American civilization.

Dropping sea levels and a change in climate have already been covered. But I have the impression that removing enormous amounts of planet stuff should influence plate tectonics. After all, planet stuff is comparably heavy (although the upper layer must be the lightest part, since the heavier stuff mostly sank to the ground when it was still molten.

Anyway. You remove gigantic amounts of heavy planet stuff, so you reduce the pressure on the relevant tectonic plate(s), which, as we know, swims on molten planet stuff, so this plate will be pushed up (due to the messed-up equilibrium), which should cause some really, really impressive earthquakes in all the fault zones and the border regions of the plate in question.

And massive earthquakes tend to get noticed.

At that time Russia was a tributary of the Golden Horde which ruled partially in Europe and partially in Asia.

At that time the Ottoman Turks were expanding from Asia into Europe, and had already moved their capital to Adrianople in Europe.

The Ottomans besieged Constantinople for 12 years from 1390 to 1402, and Emperor Manuel II traveled to western Europe to ask for help. The Ottomans also finished conquering Bulgaria in the 1390s. The Bulgarian capital Tarnovo was captured in 1393, and Tsar Ivan Shishman was beheaded when the Ottomans captured Nicopolis in 1395. The other Bulgarian Tsar, Ivan Sratsimir of Vidin, joined a crusade with western Europeans, Hungary, and Wallachia, but the crusade was crushed at the Battle of Nicopolis on 25 September 1396. The Ottomans then captured Vidin and Ivan Sratsimir, ending Bulgaria, though Constantine II and Fruzhin claimed the imperial titles and sometimes controlled small parts of Bulgarian territory.

Meanwhile, diplomatic relations between the all conquering, cruel, and terrifying Sultan Bayezid I and the even more all conquering, even crueler, and even more terrifying Tamerlane broke down. At the Battle of Ankara on 20 July 1402 the hitherto invincible Ottoman army, with contingents from European vassal states, was crushed by the army of Tamerlane, and Bayezid was captured.

The Ottoman state fragmented into several rival states led by sons of Bayezid who escaped. The "Byzantines" and Italian merchants ferried Ottoman warriors across the straits from Asia to Europe. believing they might need the help of those Ottoman warriors if Tamerlane of the mega massacres invaded Europe. That turned out to be an error, since Tamerlane turned eastward and never again came that far west. But the "Byzantine" Empire and eastern Europe did have a respite from Ottoman invasions for a while.

Eventually the Ottomans resumed their march of conquest, later in the 15th century. Hunyadi Janos, Skanderbeg, and Dracula became national heroes of their respective countries due to their active, and sometimes successful, resistance to the Ottomans.

The Hungarian army was crushed and King Louis II killed, at the Battle of Mohacs in 1526. The future Emperor Ferdinand I became King of Bohemia and King of part of Hungary. The Ottomans continued to raid and sometimes invade Europe. Vienna was besieged in 1529 and 1683, and then the tide turned and Hungary was reconquered from the Ottomans in the Great Turkish War of 1683-1700.

All the Habsburg lands, including Bohemia, and all the Holy Roman Empire, including Bohemia, contributed to the Great Turkish War.

At that time the Khanate of the Crimea, an Ottoman Vassal, was constantly sending raiding parties to capture slaves from eastern Europe, while the Barbary States in north Africa, also Ottoman vassals, were constantly capturing European ships and raiding the coasts of the Mediterranean and even occasionally as far as Ireland and Iceland.

And if all the land and people in Asia, and a large part of the populations of the Golden Horde and the Ottomans, disappeared around 1401, what would happen? Would that be better or worse for eastern Europe? Would the Ottomans be too weak to continued invading and conquering Europe, or would they turn all of their energies into invading Europe since they could no longer invade Asia?

So The disappearance of Asia would certainly be big news in Bohemia, even if most Bohemian peasants probably had only a vague notion of where Asia was. And if later news indicated that the Ottomans were a lesser threat, or a greater threat, that would be important news to everyone in Bohemia, since in real history the Bohemians were eventually taxed to pay for anti Turkish warfare to keep the Ottomans as far from Bohemia as possible.

• You mean the beginning of the 15th century was 1401, surely? – Martha Jan 31 at 18:24
• @Oops!. I have corrected that. The question asked for the beginning of the 15th century (the 15th century is 1401-1500) and I used the conditions at the beginning of the 15th century, but I wrote the 14th century. – M. A. Golding Feb 2 at 18:17

Just ignore the bits about the dragon taking off and you still have your answer: basic planetary destruction at worst, entirely planetary surface remodeling at best.

If you suddenly whisk away several billion cu km of rock (all the lands with everything on them are just gone), the rest of the planet isn't going to just sit idly by. People in central Europe won't notice, but the waters of the Arctic, Pacific, Indian & Mediterranean will suddenly begin to flood into the about 200 km deep hole in the planet. Water + 1000 deg rock = loads of explosively ejected steam.

They might notice weird effects as the crust's isosasty is suddenly disequilibrated: sudden pressure release over an area of 44 1/2 million sq km means the mantle shoots up and Europe & much of Africa sink.

Pressure relieved on the planetary core will cause it to explode.

End of all central Europeans and their momentary curiosity over the day's events.

There would be a dramatic effect on the climate, though it’s hard to say exactly what it would be without access to a climate modelling supercomputer. The dividing line between Europe and Asia is a bit arbitrary, but east winds would only be travelling over hundreds of miles of land instead of thousands, making the climate less extreme. And the Himalayas affect the climate of the whole world.

# No, at least not what actually disappeared.

What if China and its silk was still there? What if just the land in the middle disappeared and China, Mongolia and half Russia was still there? Big difference in size and economic perspectives.

And they have at least a vague idea of its size and location.

If we were talking about knowing that some land disappeared I'd say sure, like many others have. It could be religion when it tries to explain what happened. It could be someone who knows and explains to the farmers why the climate has changed. Or it could travel through gossip and merchants, it's a huge news that will be shortly confirmed by the climate after all.

But while we know that the whole thing disappeared, they'd have no way of knowing it. Maybe everything disappeared but China, making it an island. If it were any other state with lower trading importance they may just assume that it was gone, but in this case people would probably still have hope that maybe only the land in between was gone. And if Europe was still there, maybe also the other side of the continent was still there too.

But they couldn't just go there blindly hoping to find something. From the nearest point to halfway through China there are roughly 4000 km. It took seven years for Columbus to find someone who financed his travel which was, according to his estimation, of roughly the same length (3860 km). The difference is that in that case there were estimations (even if bad) while in our case there are none. In the worse case there is no land at all (they don't know that it's actually like this) and the ship is neither able to go around the earth nor able to return back.

At most they'd be able to reach the border of current China and return back, but even there, there is a big piece of land afterwards that they'd have no way to know if existed. To see if their trading partner was fully gone they'd need to travel 12000 Km in the worst case, which is way beyond what they could do at the time (or willing to do due to the costs and danger).

It's important to notice that the potential disappearance of the whole continent would prevent both Columbus' voyage and the discovery of the sea route to India below Africa. This would probably prevent the Age of Discovery from happening and also inhibit the development of long transoceanic travels far away from any land.

For this reasons it'd take more than two centuries before anyone is actually able to tell the size of what is gone and even there they'd probably just check for China and assume everything else was gone too. This would allow for islands of the size of Europe to be overlooked (like the whole east Russia), but we are not interested in precise knowledge. I'd personally say much more than two centuries, but we are already far too deep into an alternative timeline for that.

It would be the news of the century, and spread as fast as a messenger could ride to every corner of Europe. The Ottoman Empire -- aka "The Terrible Turk" was the biggest threat to Christian Europe.

Losing your neighboring threatening superpower would be a huge event. The church bells would ring out in every city, town and village, the news would be shouted form every pulpit and echoed in every street. "The LORD God has smitten the heathen, just as He smote the unbelievers in Noah's day. Mighty is the LORD!"

Expect mass pilgrimages to see the new edge of the world, and new sea trading routes to spring up overnight. And Europena poltics would change completely without a common enemy - or an Ottoman Empire to trade with.