Topic: What is wait calculation? Approximately when will we reach Proxima Centauri Using the wait calculation?
Wait calculation was introduced by Andrew Kennedy in “Interstellar travel” which is actually more difficult than interplanetary spaceflight; the distances between the planets in the solar system are less than 30 astronomical units (AU) whereas the distances between stars are typically hundreds of thousands of AU, and usually expressed in light years”. Accordingly, it is the travel between planets, usually within a single planetary system.” The Wait calculation and the incentive trap of progress”, in the journal of the British interplanetary society (JBIS) .”
The closest star to our solar system is Proximal Centauri, which is why it makes sense to plot an interstellar mission to this system first. It is a part of a triple star system called Alpha Centauri, Proxima is about 4.24 light years from earth. Alpha Centauri is actually the brightest star of the three in the system the other two stars are alpha centauri A and B, part of a closely orbiting binary 4.37 light years from earth whereas Proxima Centauri is an isolated red dwarf about 0.13 light years from the binary. It is extremely distant from the other two stars, orbiting them at a distance of around 1.2 trillion miles. Proxima Centauri burn their fuel at a much lowe rate and can therefore exist far longer. it was discovered in the year 1915 by the Scottish born astronomer Robert Innes. At a maximum velocity of 56,000 km/hr, deep space would take over 81,000 years to traverse the 4.24 light years between earth and Proximal Centauri.
If we want to send a probe six light years to the star at that speed, probably looking at a travel time of 12,000 years. It’s a lot of time but then better than 70,000- year plus travel time to the Centauri stars. 12,000 years is too many, especially in an age that regards maximum mission time as the lifetime of a researcher working on the project. If we launch that kind of mission, it would inevitably be passed enroute by a faster spacecraft. And that’s the conundrum.
For the waiting calculation, we can see that any civilization may prefer to wait until growth produces a travel time that approaches the minimum since this will also be the minimum expended energy. Successive generations will have less and less time to wait for the minimum, but , given that the average long term rate of growth does not change appreciably, any attainable velocity will lie on the same curve and the point in time where the minimum occurs does not change.
Future generations may approach this minimum point with heightened anticipation if they only have the capability to make a single launch, since leaving at any other time than the minimum is risky. Many of the trips to the more remote stars planned for the future, using the technological techniques that are expected to be available, will take place at velocities of around 0.02cand may thus take thousands of years than hundreds. Consequently, that is the fear that leaving earlier than the minimum will mean that future generations will not only arrive at these destinations earlier, having had an easier trip, but may squander all the fruits of the landfall before the original voyagers arrive.
If the civilization has the capability to make several launches, then they could make use of the spread of arrival times to encourage individuals to leave on the basis that others would either be there first to welcome them or be following close behind bringing with them the future technologies. These are referred to the wait calculations. To put the time scale to perspective, it would be over 27,00 human generations to reach Proximal Centauri.
Proxima centauri is 4,243 light – years away. Another way of understanding the vastness of interstellar distances is by scaling: one of the closest stars to the sun, Alpha Centauri, can be pictured by scaling down the earth – sun distance to one meter. On this scale, the distance to Alpha Centauri would be 271 kilometers. The fastest outward bound spacecraft yet sent, Voyager 1, has overed 1/600th of a light year is currently moving at 1/18,000th the speed of the light. At this rate, a journey to Proxima Centauri would take 80,000 years. Some combination of great speed and long travel time are required. The time required by propulsion methods based on currently known physical principles would require years to millennia.
Interstellar Medium: A major issue with traveling at extremely high speeds is that interstellar dust and gas may cause considerable damage to the craft, due to the high relative speeds and large kinetic energies involved. Various shielding methods to mitigate this problem has been proposed. Larger objects are far less than common, but would be more destructive. The risks of impacting such objects, and methods of mitigating these risks, have been discussed, but many unknowns remain.
If we trust in the continued expansion of civilization, the risks of being overtaken are real. All civilizations, including earth are caught in this incentive trap of growth. And it is an important consideration since it is perfectly possible that the colonization of space will be a competitive venture between disparate cultural groups. In which case, getting the waiting calculation wrong may be fatal since, after the minimum has passed.
Written By: Nidhi Kulhari
CP 9TH A.