Q: What’s out there?

A: “Billions”

~ Carl Sagan (1980)


What's out there?

The universe is a very big place. For an idea of just how big, check out this excellent website, which shows the scale of objects in the universe ranging from quantum foam to the entire universe itself. The possibilities out there are greater than we know and perhaps even greater than we can imagine.  More and more exoplanets (planets around other stars) are being discovered every week. Click here to see the latest tally.

Tau Zero is especially interested in habitable planets, and more specifically, how far we would have to travel to reach one. These data affect how we will design interstellar craft.

Personally (Marc Millis speaking), I would like to see the first habitable planet discovered named “Destiny.” 

Before reaching our Destiny, so to speak, what other destinations are worth visiting, and why?


What We Know is Out There

In terms of lightspeed flight time

½ day      
Voyager-1 (first interstellar craft)

1 day 
Exiting the bow shock of our sun and into open interstellar space

2 months 
Gravitational lens focal point of our sun begins

½ year 
Middle of the Oort cloud

4.2 yrs
Nearest neighboring star, Proxima Centauri

4.4 yrs
Nearest neighboring star system known to have planets, Alpha Centauri (Binary, 2-sun system)

Understanding the Universe by Envisioning Flight Through The Universe

What is spacetime made of? What can we learn about the unsolved physics of spacetime by contemplating flight through the cosmos?


Our motion through the universe can be measured by looking at the Cosmic Microwave Background.  Its waves get blue-shifted in the direction we are heading, and red-shifted in the direction we are coming from.  While cosmologists ponder the anomalous homogeneity of this background, space travelers can use it as an absolute reference frame for motion through the universe, and as clues for deciphering the stuff of space.


"To explore strange new worlds, to seek out new life and new civilizations..."

~ Star Trek


Estimated distances to new worlds, new civilizations, in terms of lightspeed flight time (For trip times at contemporary spacecraft speed, tack on 4 zeros [decimal places] to these estimates):

20 yrs Possibly nearest habitable planet

90 yrs Peak probability of habitable planet location

500 yrs Possibly nearest civilization

2000 yrs Peak probability of nearest civilization location

Image: Artist’s conception of potentially habitable exoplanets, with Earth and Mars to scale.

Credit: The Habitable Exoplanets Catalog, PHL @ UPR Arecibo.

Probability of Distance to Habitable Planets and Civilizations


These numbers are just provisional estimates at the moment.  Claudio Maccone, a Tau Zero practitioner, has been converting the simplistic Drake Equation and Fermi Paradox into more insightful, statistical forms. One of the projects that we would like to finish is to update these estimates to include the latest, most reliable data.

Content Contributors

  • Marc Millis
  • Paul Gilster

The Tau Zero Foundation is a 501(c)3 non-profit organization dedicated to pioneering advancements toward interstellar flight.