On to the stars

We call the people we send into space astronauts — sailors of the stars — and the Russians call theirs cosmonauts — sailors of the cosmos.

At the moment, we are scarcely out of our cosmic backyard, but we have ambitions. We have spacecraft that have now left the Solar System.

However it will be millennia before they pass another star. It is true that vacuum, extreme changes in temperature and radiation are problems we have to deal with when travelling in space, but the real one is time.

Landing the Perseverance rover on Mars has been a huge triumph. Getting there took months, and Mars is one of our nearest planetary neighbours in the Solar System. There are many volunteers willing to spend several months in a spacecraft, a while on Mars and several months getting back.

However, getting to the outer Solar System will take years, and getting to planetary systems of other stars will take centuries or millennia.

There have been suggestions as to how we can reach the stars. The first is to anaesthetize people so deeply they age much more slowly.

second is to build huge, self-supporting spaceships where generations pass, one after another until the remote descendants of those who set out get to actually set foot on those distant worlds.

Neither of those ideas is attractive.

The immediate thought is "Can we go faster?"

Obviously, the faster we go, the sooner we will get there. Unfortunately, there is a cosmic speed limit, the speed of light, 300,000 km/s. No material object can move through space faster than that.

At the moment our spacecraft move around at speeds in the region of 10 km/sec, so there is room for improvement there.

If we could move at, say 10% of the speed of light, we could get to Mars in a few hours and anywhere in the Solar System in a day or two.

Of course, there is no current space propulsion system capable of achieving that speed, but that is a purely technical problem and should eventually be soluble.

Even so, at that speed it would still take more than 40 years to reach the nearest star beyond the Sun. If we could reach 100% of the speed of light, it would still take four years, and tens, hundreds or thousands of years to explore our neighbourhood in our galaxy, the Milky Way.

Even more unfortunately, as we approach the speed of light, funny things happen to time. At 99% of the speed of light, a year as experienced by the astronauts would be seven years as experienced by our family and friends back home.

People have described interstellar distances as "God's Quarantine Regulations," and that seems right.

Science fiction writers solved the problem by invoking warp drive, or space warp, where space is folded in some way so that our travellers end up very close to their destination. Imagine two ants on opposite edges of a piece of paper getting together without walking by folding or warping the paper.

At the moment, warp drive and space warp remain in our imaginations.

Still, looking at the things we have achieved since the year 1900, who back then could have predicted the hi-tech world we live in now.

We are learning more and more about the structure of space and time, and every day seems to show us it is more complicated and less well understood than we thought the day before.

I think the only thing that will stop us reaching the stars is the possibility we will wipe ourselves out first, either as a civilization, or as a species.

The need to know what's on the other side of that hill or ocean is part of us.

  • At 09:37 Universal Time on March 20, the Sun will cross the equator, heading north. That is, 04:37 EST, or 01:37 PST, on the same date. On this day the Sun will rise exactly in the East, set exactly in the West, and will be above the horizon for 12 hours.
  • Mars is high in the southwest after dark.
  • The Moon will reach First Quarter on the 21st.


Comments are pre-moderated to ensure they meet our guidelines. Approval times will vary. Keep it civil, and stay on topic. If you see an inappropriate comment, please use the ‘flag’ feature. Comments are the opinions of the comment writer, not of Castanet. Comments remain open for one day after a story is published and are closed on weekends. Visit Castanet’s Forums to start or join a discussion about this story.

More Skywatching articles

About the Author

Ken Tapping is an astronomer born in the U.K. He has been with the National Research Council since 1975 and moved to the Okanagan in 1990.  

He plays guitar with a couple of local jazz bands and has written weekly astronomy articles since 1992. 

Tapping has a doctorate from the University of Utrecht in The Netherlands.

[email protected]

The views expressed are strictly those of the author and not necessarily those of Castanet. Castanet does not warrant the contents.

Previous Stories