Well, to continue the side track (but an integral part of what is going to happen in the next months) Thus far in the world's modern history, only small countries default on their payments and obligations. They have sold Bonds to companies and large investors (pension funds etc.) promising to pay the Loan + n Interest at a fixed date in the future. Typically five or more years and these are considered safe investments because countries don't go bust.
However if, in order to meet payment, the country has to print yet more money? They devalue their currency. If the Corporate investors do not get the full amount that they are expecting? They cannot meet their obligations and the Dominoes start to fall. If a company has debts that are more than the value of it's assets and income, it goes bust. What happens when a country cannot pay it's debts?
Of course, it may not happen...
What matters is that - when considering the next months and years, this may not be a Recession of the kind that we have seen in the last 50 years. We have already seen that the US Fed dropped interest rates very quickly and it had almost zero impact on the market. Which is no surprise, although the fed might be. So, in the first few weeks of the crisis they have fired off their big guns - and the markets still continue to fall.