Many people are getting resettled after the recent school vacation week and while, according to a recent news story, one of the most popular vacation destinations for Mainers is Florida — same ocean, just much warmer — there are many oceans to visit farther afield.

In addition to our vast Atlantic Ocean, the other three official oceans are the Indian, Pacific and Arctic, with the Antarctic Ocean sometimes counting as a fifth. There are many seas on top of that like the Mediterranean, the Caribbean, the Adriatic and the Red Sea to name a few. Some of these, like the Red Sea, are less hospitable to life than others.

The same could be said of the Red Planet — that’s where a recent inspection of some high-resolution photographs have revealed the likelihood that there was once an ocean there. There has long been debate about whether other planets, including Mars, could have once supported life or even might in the future. In the case of the ocean on Mars, it would have been there somewhere in the 3-4 billion years ago range. A variety of evidence points to its existence, including sedimentary deposits that are similar to those found along the shores of Earth’s currently existing oceans.

What makes this particularly interesting is that the existence of an ocean means the possible existence of life. The origins of many of planet Earth’s earliest life forms can be traced back to our oceans. Tiny microbes and other single-celled organisms evolved in those briny environments where land meets sea. The same may have been true on other planets. Apparently, if there were creatures that once lived on Mars, the ocean they experienced would have been a relatively calm one surrounded by sandy beaches — perhaps not too far off from those that many Mainers seek out in Florida.

Oceans provide much of the building blocks for life on a planet, but freshwater is a necessity for many as well. The ocean on Mars is thought to have been fed by small rivers and streams. The photographs taken with the Perseverance rover showed ancient river deltas in addition to an ocean basin.

Old oceans may seem like a thing of another planet. But Earth is full of plenty of oceans that no longer exist. They have shaped our landscape as well as the life around them, some of which incongruously still exists. What is known as the Western Interior Seaway once split North American in half and went through a part of the country where it is now hard to imagine there could ever have been an ocean. A funny reminder, however, is the fact that pelicans still live in some of these now desert and mountainous environments. That’s despite the fact that the ocean hasn’t been there for over 100 million years.

While, in reality, Mainers aren’t flocking to Mars for the sandy beaches, it is interesting to think about both how crucial oceans are to planetary life and how immense and permanent they can seem on our own planet.

Susan Olcott is the director of strategic partnerships at Maine Coast Fishermen’s Association.