Question

Each of the following describes some futuristic scenario that, while perhaps entertaining, may or may not be plausible. In each case, decide whether the scenario is plausible according to our present understanding of science or whether it is unlikely to be possible. Explain clearly; because not all of these have definitive answers, your explanation is more important than your chosen answer. A brilliant teenager working in her garage discovers a way to build a rocket that burns coal as its fuel and can travel at half the speed of light.

Short answer

The scenario is implausible according to current science.

Step-by-step solution

Examine Current Rocket Technology

Currently, rockets use various types of fuels, including liquid hydrogen and RP-1 (a highly refined form of kerosene). These fuels are used because they have high energy efficiency and produce a lot of thrust necessary to launch a rocket into space. Coal, on the other hand, is a solid fuel that doesn't have the necessary energy density or efficiency for space travel as compared to current rocket fuels.

Understand Speed of Light Limitations

According to the theory of relativity, no object with mass can travel at the speed of light. Speeds approaching half the speed of light are incredibly high and require enormous amounts of energy. The problems associated with propulsion at such high speeds include increased mass as per relativistic physics and the need for immense amounts of propellant to sustain such speeds.

Evaluate the Feasibility of Home-Built Rockets

Building a simple rocket in a garage is theoretically possible with available materials and knowledge. However, creating a rocket that could reach speeds close to half the speed of light is currently beyond our technological capabilities and infrastructure, especially for an individual without significant resources and advanced facilities.

Analyze Scientific Plausibility

Putting all these points together, it becomes clear that a coal-powered rocket capable of reaching half the speed of light is implausible based on our current scientific understanding. The energy requirements, physics constraints, and limitations of current materials make this scenario unlikely.

Key concepts

Rocket Technology

Rockets are fascinating pieces of technology used to propel objects into space. They operate by expelling exhaust gas at high speeds to push the rocket in the opposite direction, following Newton's third law of motion. Most modern rockets use liquid or solid propellants with high energy efficiency. For instance, liquid hydrogen combined with liquid oxygen is common in vehicles like the Space Shuttle.

These fuels are selected due to their high energy density, which is essential for producing the necessary thrust. Thrust is what allows rockets to overcome Earth's gravity. Coal as a rocket fuel is impractical because it does not provide sufficient energy density needed for such a task.

• Current fuels are optimized for high-energy and high-thrust production.
• Rockets must overcome Earth's gravitational pull, demanding high efficiency.
• Coal, being less efficient, cannot match modern fuel standards for space travel.

Energy Density

Energy density refers to how much energy is stored within a given amount of fuel. It is a crucial factor in selecting propellants for rocket technology as it influences the amount of thrust produced.

Liquid hydrogen, with its light weight and high energy yield, provides a perfect example of an ideal rocket fuel with high energy density. On the contrary, coal's energy density is significantly lower.

Consider the following:

• High energy density fuels store extensive energy in small volumes.
• Higher energy density leads to more efficient propulsion systems.
• Coal's energy density doesn't suffice for the rigorous demands of space travel.

Speed of Light Limitations

When discussing high-velocity travel, such as approaching the speed of light, physics imposes several constraints according to Einstein's theory of relativity.

As objects speed up and approach the speed of light, their mass effectively increases, requiring more and more energy for further acceleration. This makes reaching half the speed of light require exponential energy increases and significant technological advancements, which our current understanding and technology do not currently support.

• Relativistic effects become significant at high speeds.
• Energy requirements soar as speed approaches the speed of light.
• The mass increase is a limiting factor for vast speed travel.

Scientific Feasibility

The feasibility of scientific proposals must be balanced against our current understanding and technological abilities. While the concept of a garage-built coal-powered rocket shooting across the cosmos is thrilling, our scientific principles and technology don't yet allow it.

Creating such a rocket necessitates overcoming substantial hurdles including energy supply, material strength, and propulsion capability. Given these demands, alongside the limitations outlined by current science like relativity, such a scenario remains within the realm of science fiction for the time being.

• Projects must align with established scientific laws and technologies.
• While ambitious, garage-built rockets approaching light speed are implausible today.
• The energy and technology gaps are substantial barriers to these achievements.