In 2012, James Cameron, creator of Avatar and Titanic, became the first person to reach the Challenger Deep. When he arrived at the deepest spot on Earth at 7 miles below sea level, he spent hours mapping the region and taking photos and samples.

“As human beings, we’re drawn to absolutes—the deepest, the highest, the coldest, the farthest.” he says. “And as a storyteller and curious monkey, I just wanted to see what was there.” The answer is obvious—plastic and more. “Our so-called civilization is using the ocean as its toilet,” Cameron says. “Unless this changes, ocean ecosystems are going to continue their rapid collapse.”

Despite decades of environmental studies, the impact of plastic and other forms of pollution on oceans are not entirely understood. Initial studies appear to indicate that ingesting them-either directly or indirectly-could cause disease. Plastics can also release poisonous substances into the water, which could potentially impact animal populations.

But plastic is just one of the problems facing oceans that have yet to be fully understood. “Plastic waste in the ocean is horrifying but is only the most obvious of our many deadly waste streams, which include carbon that’s heating the atmosphere and making the ocean acidic, and the run-off nutrients from all the world’s agriculture, which is causing anoxic dead zones the size of countries,” Cameron says.

Oceans, like the rest of the world, are impacted by the burning of fossil fuels and the release of greenhouse gases like carbon dioxide-about 30 percent of which is absorbed by the sea. This absorption causes ocean acidification, where the pH level is altered to become more acidic. As a result, it’s harder for some creatures to form shells and skeletons and countless species at the base of the food web can struggle to survive, which, scientists say, has the potential to cause huge disruptions to entire ecosystems. Indeed, ocean acidification is thought to have played an important role in Earth’s worst-ever mass extinction event 252 million years ago.

The effect of climate change on the world’s oceans will likely worsen in coming decades. Last June, scientists announced carbon dioxide levels had reached the highest levels since human records began. The last time carbon dioxide levels were this high was during the Pliocene era, between 3 and 5 million years ago, when global temperatures were about 4 degrees Celsius warmer than they are today. Current climate models suggest that if greenhouse gas emissions continue on their current trend, we may be on course to see 4 degrees of warming by 2100.

As a result, understanding the role oceans have on global systems is becoming more and more important.

Theory of mind refers to the ability to understand the desires, intentions and beliefs of others, and is a skill that develops between 3 and 5 years of age in typically developing children.

Theory of mind is damaged in some people with autism(自闭症). One of the earliest tests for theory of mind is the false-belief test developed by Simon Baron-Cohen and Uta Frith. In the classic version of the test, a little girl named Sally puts a ball into a basket and goes out for a walk. While she is away, another little girl named Anne takes the ball out of the basket and puts it into a box. When Sally comes back, she wants to play with the ball. Where, the children are asked, will Sally look for the ball? Children with autism, unable to take an alternative perspective, would assume Sally has reason to believe that the ball has moved.

In 1985, Baron-Cohen, Frith and Alan Leslie reported that children with autism systematically fail the false-belief test. The researchers concluded that autism leads to a delay in the development of theory of mind, and that people with autism have difficulty understanding the mental states of others.

However, researchers stress that it is important to distinguish false-belief tasks, which rely on language, from completely-developed theory of mind, which is more deeply damaged in people with autism. Some children and adults with autism can pass false-belief tests, for example. But they show more difficulty with theory of mind tasks that do not allow them to reason through a problem. For example, a 2011 study reported that highly intelligent young adults with autism tend not to weigh intention and outcome when engaged in moral reasoning.

Finally, much research suggests that different aspects of language are important for developing theory of mind. These include communication in social contexts, such as between mother and child or in peer interactions with words and concepts referring to mental states and complex grammar, especially sentence structures used to express mental states.

The ocean bottom, a region nearly 2.5 times greater than the total land area of the earth, is even today largely unexplored. Until about a century ago, the deep ocean floor was completely inaccessible and hidden beneath waters averaging over 3,600 meters deep. Totally without light and in the case of intense pressures hundreds of times greater than at the earth’s surface, the deep-ocean bottom is a strange environment to humans, in some way, as fighting and remote as the outer space.

Although researchers have taken samples of deep-ocean rocks for over a century, the first detailed global study of the ocean bottom did not actually start until 1969, with the beginning of the National Science Foundation’s Deep Sea Drilling Project(DSDP). Using techniques first developed for the offshore oil and gas industry, the DSDP’s drill ship, the Glomar Challenger, was able to maintain a steady position on the ocean’s surface and drill very deep waters, taking samples of rocks from the ocean floor.

The Glomar Challenger completed 96 voyages in a 15-year research program that ended in November 1983. During this time, it sailed 600,000 kilometers and took almost 20,000 samples of rocks around the world. Those samples have allowed geologists to reconstruct what the planet looked like hundreds of millions of years ago and to make out what it will probably look like millions of years in the future. Today, largely on the strength of evidence gathered during the Glomar Challenger’s voyages, nearly all earth scientists agree on the theories of plate tectonics (构造学) and continental drift that explain many of the geological processes.

The sample of rocks drilled by the Glomar Challenger has also provided a climatic record stretching back hundreds of millions of years. The information of past climatic change can be used to predict the future climate.