Seth Shostak, senior astronomer for the SETI Institute in California, thinks there's a reason we haven't yet found proof of alien life: politicians. And unfortunately, Shostak thinks this will be the reason we don't find evidence in the future.

Although space is rampant with possibilities of alien life, the problem with getting out there and finding it comes down to one major issue: it's expensive. And with budgets shrinking for national space programs, thanks to politicians, it's getting harder than ever to prove that there's life outside of Earth.

However, with an unlimited budget, many scientists believe we'd have proof within our lifetimes.

We weren't always so adamant that life existed beyond the stars, but NASA's Kepler mission changed that. The spacecraft's mission was to find exoplanets, or planets outside our solar system orbiting their own star, rather than our Sun. To date, Kepler has confirmed the presence of nearly 1,000 such planets, some which could be nearly identical to our Earth. That suggests that other Earths are out there, and those other Earths could be teeming with life.

Kepler data suggests that there are probably more of these Earth-sized planets and that as many as one in five stars could host such a planet. Considering the vast number of stars out there, there could be tens of billions of other Earths waiting for discovery.

So why aren't we out there looking for them? It all comes down to money. Searching for alien life is expensive. So we've focused our efforts nearby, particularly on Mars. Although we don't believe Mars currently hosts any alien life, even microbial, there's a chance that it once did. We currently have a vehicle on Mars studying it and NASA is also planning another mission in 2020.

However, even NASA's budget has seen cuts recently. So although the agency wants to explore Mars further, it is not feasible with their current level of funding, at least according to the National Research Council.

"Absent a very fundamental change in the nation's way of doing business, it is not realistic to believe that we can achieve the consensus goal of reaching Mars," says Mitch Daniels, the former Indiana governor and co-chair of the committee.

This means that we also can't pursue potential life on the Jupiter moon Europa, which is one of the most likely candidates in our universe for sustaining life. We already know the planet contains water, which is one of the fundamental things needed for life.

Better spacecraft and telescopes, along with equipment that can pick up radio signals from the skies, requires money that isn't being freed up for such projects.

In 2015, the NASA budget was only $2.5 billion. This may seem like a lot, but spread out over its various missions in science, astrophysics and the James Webb space telescope, it is very little, about one-thousandths of the total U.S. federal budget. SETI, whose primary goal is searching for alien life, has an even smaller budget.

However, there is hope on the horizon. Many privately-owned companies are getting in on space exploration, including Elon Musk's SpaceX. Without having a government to answer to, at least when it comes to money, SpaceX, and other organizations like it, may help us find E.T. after all.