Let’s say you really care about the American space program. You want the United States to return to the Moon, go to Mars, and maybe capture an asteroid. You hope we might put a submarine in Europa’s subsurface ocean or possibly deploy aerostats above Venus’s acid clouds. Oh, and don’t forget about the James Webb Space Telescope!

Let’s say space exploration is a top priority for you. In fact, let’s say it is your #1 political issue. So how should you vote?

On Monday, I made the argument that Republicans are generally more pro-NASA than Democrats. But that doesn’t mean we, as space enthusiasts, have to vote Republican (thank goodness, especially this year). In fact, Republicans tend to set goals for NASA that sound exciting but are perhaps a little too ambitious; you could argue that Republicans just set NASA up to fail. Meanwhile Democrats don’t seem to object to space exploration, but they’d prefer to spend federal dollars elsewhere.

This puts us space policy voters in an awkward position. What do you do when you care about a political issue but that issue doesn’t fit neatly into either the Republican or Democratic camps?

One option is to join an advocacy group (also known as a special interest group). Here are three influential organizations that lobby Congress in support of space exploration:

• The Mars Society: The Mars Society is focused on one and only one goal: colonizing Mars. Specifically, they advocate for the Mars Direct plan developed by Robert Zubrin. Under that plan, either NASA or a partnership between NASA and foreign space agencies would establish a small outpost on Mars within ten years. Subsequent missions would then expand that outpost into a full-fledged colony. Click here for more on the Mars Society.
• The National Space Society: The National Space Society, or N.S.S., supports human settlement all across the Solar System, not just on Mars. Their plans include the Moon, Mars, orbital space stations, the asteroid belt… basically they want humans to set up shop wherever possible. Click here for more on the N.S.S.
• The Planetary Society: The Planetary Society has some pretty big names behind it. It was founded by Carl Sagan and is currently headed by Bill Nye the Science Guy. They’re more focused on robotic space exploration than human space flight, and they’ve done a pretty respectable job convincing Congress to not slash NASA’s planetary science budget (or at least not slash it by too much). Click here for more about the Planetary Society.

Obviously joining any of these groups costs money, but you don’t have to spend zillions of dollars. Small contributions can make a surprisingly big difference for these kinds of organizations.

I just recently rejoined the Planetary Society after letting my membership lapse for a few years. I don’t have much money to spare, but I care enough about space exploration that I want to support it where I can. Also, their quarterly magazine is pretty informative.

I think many people get frustrated with American politics because some issues (like space policy) just don’t seem to fit into the two-party system. So if there’s a political cause you care about, especially if it’s not clearly identifiable as a Democrat issue or a Republican issue, consider joining an advocacy group. Voting is not the only way you can make your voice heard.

It’s an election year here in the United States. As a blogger, I’m pretty sure I am legally obligated to rant about politics during an election year. Also, as I continue my research about space, I am becoming increasingly aware of how American politics and space exploration are intertwined.

First off, our Solar System is divided between red planets and blue planets.

The partisan divide on space exploration might surprise you. Republicans, famous for wanting to reduce spending everywhere possible, tend to support NASA; Democrats, who generally support more government spending, usually try to cut NASA’s budget.

As an example, you may recall that Newt Gingrich, former Republican Speaker of the House, not only wanted America to return to the Moon but also wanted to make the Moon America’s 51^st state. Meanwhile, President Barack Obama put and end to the space shuttle program.

I want to be fair here. When the Obama Administration canceled the space shuttle program, I was disappointed, but that decision paved the way for private companies like SpaceX to get into the space exploration game, which will probably be a good thing in the long run. And as much as I do want America to return to the Moon, that whole 51^st state idea was a bit kooky.

Still, Republicans are generally more supportive of NASA than Democrats (except when NASA is doing climate change research). Please do not assume that this makes me a Republican. I have strong opinions about a number of other political issues. Space exploration actually ranks pretty low on my list of priorities when I vote in federal elections.

Fortunately, you don’t have to vote Republican to show your support for space exploration. There are other options, which I’ll review in greater detail on Wednesday.

You may remember that the Voyager 1 spacecraft officially “left the Solar System” back in 2012, bidding us all a fond farewell.

Specifically, Voyager 1 crossed a boundary known as the heliopause, beyond which the solar wind no longer blows. Out there is true interstellar space, in the sense that the ionized particles Voyager encounters and samples are more likely to come from other stars or other sources than our Sun.

However, Voyager 1 has not quite left the Solar System.

This depends a bit on how we define our terms (as so many things do in science), but by one fairly conventional definition, anything that orbits the Sun (or, like the Moon, anything that orbits something that orbits the Sun) is part of the Solar System. So taking that into account, just how big is the Solar System, and where exactly does the Solar System end?

• Earth: By definition, Earth orbits the Sun at an average distance of 1 astronomical unit (AU). Obviously the Solar System is larger than 1 AU.
• Neptune: As the most distant known planet, Neptune orbits the Sun at distance of roughly 30 AU. Neptune’s orbit is an important boundary line in astronomy, but it’s definitely not the end of the Solar System.
• The Kuiper belt: The Kuiper belt, the region Pluto calls home, extends from 30 AU to about 50 AU.
• The heliopause: Voyager 1 crossed the heliopause at about 121 AU.
• Voyager 1: As of the writing of this post, Voyager 1 is just over 134 AU from the Sun.
• Sednoids: By definition, sednoids come no closer to the Sun than 75 AU, but they’re free to travel much, much farther away than that. Sedna, the first known sednoid and the object for which this category of objects is named, reaches a maximum distance of about 936 AU from the Sun.
• Planet Nine: If such a planet exists (and that’s still a pretty big if), its orbit is estimated to range somewhere between 200 and 1,200 AU from the Sun.
• The Oort cloud: The Oort cloud has not yet been observed directly, but its existence is inferred from the orbits of long-period comets. It is believed the Oort cloud exists somewhere between 2,000 and 200,000 AU from the Sun.

By the way, Alpha Centauri is 4.35 light years away, which equals about 275,000 AU. If the Oort cloud does extend all the way out to 200,000 AU, that means our Oort cloud and Alpha Centauri’s Oort cloud might overlap (assuming Alpha Centaur has its own Oort cloud).

It would be interesting to know how two overlapping Oort clouds interact with one another and how many comets, asteroids, dwarf planets, etc have been exchanged from one cloud to the other. If only we had a space probe that could go check on that.