Okay, so the universe is so huge there must be some intelligent life out there, Kepler is finding lots of planets relatively nearby, and Voyager 1 has found some things about interstellar space to be careful about . . .

But if we want to send probes (or even humans!!!) to nearby stars--where do we aim our spacecraft?!? Is that type of interstellar travel even remotely possible?!?

Our Galactic Neighborhood

Okay, let’s roll out the map here and take a look at the nearby region of our Sun--let’s say 100 light years in all directions. Egads! That’s huge. Too many stars--there are 3,867 of them that we know of, not including our own Sun, but there are probably about triple that number that we don’t know about.

I can’t choose from that number, so let’s shrink it to 50 light years.

Wow! There are still about 2,000 stars within this range, but we can highlight some of the more interesting star systems and get a general overview map like at the link below:

http://www.atlasoftheuniverse.com/50lys.html

But thinking on it a bit more, 50 light years is still a hella long distance. At the speed of light, that’ll take about 50 years to reach. But there’s no feasible way for us to get up to the speed of light. Maybe, using technologies like light sails or some other technology that wouldn’t take too long to develop, we can get up to 20% the speed of light or so. Under that scenario, fifty light years would then take us 250 years to reach--way too long.

So, let’s scale it down again. Let’s limit our travels to 10 light years distant! That’s a 50 year trip at the outside at 20% light speed. The Voyagers have been operating for 40 years now, so that doesn’t seem unrealistic. Within 10 light years from the Sun, there are 7 star systems containing 11 stars, and 2 brown dwarf systems that we know of. Let’s start our search there, simply because we *might* be able to reach them in a reasonable timeframe.

But wait a second. Can we really reach 20% the speed of light? The answer is probably "Yes"!

Light Sails and Breakthrough Starshot

Okay, what are light sails? These are essentially spacecraft with thin sail-like mirrors or similar reflective surfaces that use focused laser light to propel them. An example illustration (courtesy NASA) is shown below.

One such project to make these was announced in April 2016, called ‘Breakthrough Starshot.’ Breakthrough Starshot is backed by venture capitalist, Yuri Milner, as well as Stephen Hawking, Mark Zuckerberg and many US universities (Cornell, Princeton, CalTech, UC Berkeley, and a lot more).

The goal? Propel a spacecraft (or fleet of spacecraft) weighing just a few grams to 20% the speed of light to reach nearby stars. Estimates are the program will cost $5-$10 billion and the goal is to launch the first craft by 2036. There is currently $100 million in funding for the project.

https://en.wikipedia.org/wiki/Breakthrough_Starshot

Yeah, yeah, yeah . . . there are always these “pie in the sky” projects that never amount to anything. But, times may be changing. What if I told you the project had already accomplished its first space mission?!?

It’s true. On July 26, 2017, Breakthrough Starshot launched the ‘Sprites’ prototypes attached to two other satellites. These 3.5 x 3.5 centimeter-sized prototypes weighing 4 grams contain solar panels, sensors, radios, and computers that a real mission would use. The radio systems they are using are evidently quite novel.

https://breakthroughinitiatives.org/News/12

The Sprites are currently in orbit and working perfectly. The initial technology test has been successful! And the team is very active at solving some of the problems that come with interstellar missions. Just look at the following page that contains discussions around a list of challenges the team is trying to solve. It’s pretty fascinating, even if I don’t fully understand half of the details they are talking about.

http://breakthroughinitiatives.org/Challenges/3

For example, one challenge is interstellar dust. When you travel at 20% the speed of light, a minute piece of dust (which there is a lot of out there in space) can hit a spacecraft and create a 4 mm hole in strong metal. How do you protect against that while keeping the spacecraft ultra-light?!?

Or, passing a planet in a star system, how do you take a stable photograph of it when you are literally traveling at 20% the speed of light? You are traveling the distance between the Earth and the Sun in about 42 minutes! How do you keep a camera pointed exactly at a distant object, whose position in the “sky” will constantly be changing (because of your huge speed) quite dramatically.

Final Analysis

So, we’ll see how far Breakthrough Starshot gets in coming years. This would be a huge breakthrough, with enormous advances in various technologies.

So, in the next essay, let’s think about where exactly we should head . . .

Previous Science Escape essays:

https://caucus99percent.com/content/science-escape-1-universe

https://caucus99percent.com/content/science-escape-2-our-interstellar-sp...

https://caucus99percent.com/content/science-escape-3-kepler-mission