What is the scientific notation for the mass of Halley's Comet?

What is the scientific notation for the mass of Halley's Comet?

• A. 2.2 x 10^12 kg
• B. 2.2 x 10^15 kg
• C. 2.2 x 10^14 kg
• D. 2.2 x 10^13 kg

Answer: (C)

The idea being tested is recognizing the right scale for a celestial object's mass and expressing it in scientific notation. Halley’s Comet is a small solar-system body, so its mass is huge in everyday terms but still tiny compared with planets. Estimates place its nucleus mass around a few times 10^14 kilograms. Among the options, 2.2×10^14 kg fits that order of magnitude and is a plausible, commonly cited value for the comet’s mass. The other numbers differ by large factors, implying masses that are either far too small or far too large for a single comet nucleus given its size and density. So, 2.2×10^14 kg is the appropriate scientific notation for Halley’s Comet’s mass.

The idea being tested is recognizing the right scale for a celestial object's mass and expressing it in scientific notation. Halley’s Comet is a small solar-system body, so its mass is huge in everyday terms but still tiny compared with planets. Estimates place its nucleus mass around a few times 10^14 kilograms. Among the options, 2.2×10^14 kg fits that order of magnitude and is a plausible, commonly cited value for the comet’s mass. The other numbers differ by large factors, implying masses that are either far too small or far too large for a single comet nucleus given its size and density. So, 2.2×10^14 kg is the appropriate scientific notation for Halley’s Comet’s mass.