Before we can answer this question, we need to decide what poverty is. I think that any reasonable definition of poverty would imply a lack of income or assets, so this is the definition I will use: poverty is a relative or absolute lack of income and/or assets.
So, why is poverty like a vacuum? Because neither poverty nor a vacuum is a ‘something’; both are a lack of something. In the case of a vacuum, there is a relative or absolute lack of material (atoms) in the space in question. In the case of poverty, there's a relative or absolute lack of income and/or assets. The point is, in both cases we are not dealing with a ‘something’ but a lack of something. Poverty is not like smallpox or food. Poverty is a shortage of something—income or assets.
To overcome a lack of income or assets, one acquires income or assets, just like to cure a vacuum one introduces molecules into the space. How does one acquire income? One method is stealing, but this will put you in jail. A second method is printing money (counterfeiting), but this will also put you in jail. You can also be given money, but getting large sums this way is unlikely. The usual way to obtain income and accumulate assets is to do something for someone else that they wish done and for which they will be happy to pay you money. This is usually called a job. (In this sense, even Bill Gates has a ‘job’.)
Therefore, it can be seen that poverty is the natural state of affairs. If you do nothing, you will not acquire monetary income and/or assets and therefore you will be in the state called poverty. How rapidly and how far you go from this state depends on how much you do for others (customers or employers) and how valuable these others consider your contribution. (If you don’t like their valuations, you seek a better job or business.)
Can one go from a state of non-poverty to poverty? Of course. One can lose his job or one can lose assets through such things as unfortunate investments, lawsuits, etc. But this should be a temporary state. When one gets a new job (does something for others that they want and will pay for), one again moves away from poverty.
Moral Implications
Now that we understand the nature of poverty a little better, are there any moral implications of poverty (or wealth, for that matter)? No! You must know why someone is poor or wealthy before you attempt a moral assessment.
One person refuses to work for money (get a job). Another person helps people who cannot or will not pay for his services and gives most of what he does receive to others (a missionary). A woman’s husband has left her and she is limited in the kind of job she can take on because she has small children at home. Another person keeps getting fired from jobs because of theft. You are likely to have a different moral perspective on the situation of each of these people.
What about your opinion of people who are wealthy. First, are we talking about a rich drug dealer or are we talking about someone like Edwin Land, who provided people who wanted them with both polarizing lenses and with the ‘instant camera’ which gave people a picture immediately without need for later development of the film. Morally, it makes a difference why someone is rich or poor, not whether they are rich or poor.
Now when someone implies that a continuing state of poverty is something that ‘happens’ to some people, like catching smallpox, you can explain it to him. And when you hear people imply that the poor are morally superior to the wealthy, or vice versa, you can enlighten them that you need to know why they are rich or poor before you can make any moral assessment.