Using Natural Celestial Bodies as a Power Source for Spaceships, Let Light Sails and Electric Sails Take Us Across the Universe |

The interstellar journey is an attractive and very challenging study, because the universe is far away, the nearest star “Proximity Star” is more than 4.2 light years away, and the fastest spacecraft “Navigator 1” is now 73,000 years old. . To get there, it is not realistic to want speeds like interstellar travel.

Traditional rockets accelerate by burning fuel. More fuel is needed at a faster speed, but the weight of the fuel also makes it difficult to accelerate the rocket, so it needs more fuel to accelerate. Basically, traditional fuel rockets cannot be used for interstellar travel.

The use of “light sailing” may be the solution, the principle is like a sailing ship in the sea, but the light sailing is not connected to air molecules but to photons, and uses the small impulse of photons to advance. Although this type of propulsion is weak, the universe is filled with brilliant celestial bodies, and the spacecraft can continue to gain momentum.

A recent study explored the use of these natural objects as an energy source for spacecraft, and calculated the feasibility of accelerating to near the speed of light, studying light candles and more innovative “electric candles”. The principle of electric candles is similar to that of light candles, but the surface of the candle is replaced by an invisible electric field, which receives charged particles to gain momentum. The ESTCube-1 launched in 2013 is the electric sailing satellite.

The researchers used the sun, massive stars, supernovae (SNe) and active galaxy nuclei (AGN) as light sources to power the sail. The luminosity of these light sources determines the maximum speed that the dinghy can reach. The sun is too weak, but the light from the massive stars can accelerate the spacecraft to a small percentage of the speed of light. Using SNe and AGN can even get close to the speed of light, close enough to achieve interstellar travel!

▲ The ratio between lightness and speed of Guangfan terminal. (Source: AAS NOVA, same below)

However, the spacecraft needs time to accelerate, and the author also studies the acceleration time required to reach speeds of 5%, 10%, and 20%, depending on the luminosity of the light source. For SNe, although the luminosity is extremely large, the duration of the explosion may not provide sufficient acceleration. In contrast, AGN’s maximum luminosity can be maintained for almost 100 million years, and the acceleration time of months or even years is not a problem at all.

▲ The relationship between luminosity and required acceleration time.

The author also mentioned that such light candles or electric candles cannot be built at this stage of industrial technology, but according to the theoretical feasibility and limitations of physics in interstellar spacecraft, perhaps advanced alien civilizations will also create such spaceships. Yes, we can find the huge surface of the candle!

(This article is reproduced with permission from the Taipei Planetarium; source for first image: NASA)

Further reading: