5.6 - Astrophysics and Cosmology

Understand that a gravitational field is a region where a mass experiences a force.

Use - gravitational fields to connect the rule to the data and decision in the question.

This matters because - gravitational fields determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply - gravitational fields to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: - Gravitational fields is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Understand gravitational field strength g = F/m and use this relationship.

Use - gravitational field strength to connect the rule to the data and decision in the question.

This matters because - gravitational field strength determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply - gravitational field strength to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: - Gravitational field strength is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Use Newton's law of gravitation F = Gm1m2/r².

Use - newton’s law of universal gravitation to connect the rule to the data and decision in the question.

This matters because - newton’s law of universal gravitation determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply - newton’s law of universal gravitation to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: - Newton’s law of universal gravitation is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Derive and use g = Gm/r² for the gravitational field due to a point mass.

Use - gravitational field due to a point mass to connect the rule to the data and decision in the question.

This matters because - gravitational field due to a point mass determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply - gravitational field due to a point mass to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: - Gravitational field due to a point mass is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Use Vgrav = −Gm/r for gravitational potential in a radial field.

Use - gravitational potential in a radial field to connect the rule to the data and decision in the question.

This matters because - gravitational potential in a radial field determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply - gravitational potential in a radial field to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: - Gravitational potential in a radial field is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Be able to compare electric fields with gravitational fields.

Use - electric and gravitational fields comparison to connect the rule to the data and decision in the question.

This matters because - electric and gravitational fields comparison determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply - electric and gravitational fields comparison to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: - Electric and gravitational fields comparison is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Be able to apply Newton’s laws of motion and universal gravitation to orbital motion.

Use - orbital motion to connect the rule to the data and decision in the question.

This matters because - orbital motion determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply - orbital motion to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: - Orbital motion is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Understand what is meant by a black body radiator and be able to interpret radiation curves for such a radiator.

Use - black body radiation curves to connect the rule to the data and decision in the question.

This matters because - black body radiation curves determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply - black body radiation curves to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: - Black body radiation curves is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Be able to use the Stefan-Boltzmann law equation L = σAT4 for black body radiators.

Use - stefan-boltzmann law to connect the rule to the data and decision in the question.

This matters because - stefan-boltzmann law determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply - stefan-boltzmann law to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: - Stefan-Boltzmann law is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Use Wien's law λmaxT = 2.898 × 10^−3 m K for black-body radiators.

Use - wien’s law to connect the rule to the data and decision in the question.

This matters because - wien’s law determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply - wien’s law to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: - Wien’s law is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Use radiation intensity I = L/(4πd²), where L is luminosity and d is distance from the source.

Use - radiation intensity from luminosity and distance to connect the rule to the data and decision in the question.

This matters because - radiation intensity from luminosity and distance determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply - radiation intensity from luminosity and distance to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: - Radiation intensity from luminosity and distance is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Understand how astronomical distances can be determined using trigonometric parallax.

Use - distance by trigonometric parallax to connect the rule to the data and decision in the question.

This matters because - distance by trigonometric parallax determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply - distance by trigonometric parallax to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: - Distance by trigonometric parallax is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Understand how astronomical distances can be determined using measurements of intensity received from standard candles (objects of known luminosity).

Use - distance by standard candles to connect the rule to the data and decision in the question.

This matters because - distance by standard candles determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply - distance by standard candles to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: - Distance by standard candles is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Be able to sketch and interpret a simple Hertzsprung-Russell diagram that relates stellar luminosity to surface temperature.

Use - hertzsprung-russell diagram to connect the rule to the data and decision in the question.

This matters because - hertzsprung-russell diagram determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply - hertzsprung-russell diagram to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: - Hertzsprung-Russell diagram is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Understand how to relate the Hertzsprung-Russell diagram to the life cycle of stars.

Use - hertzsprung-russell diagram and stellar life cycles to connect the rule to the data and decision in the question.

This matters because - hertzsprung-russell diagram and stellar life cycles determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply - hertzsprung-russell diagram and stellar life cycles to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: - Hertzsprung-Russell diagram and stellar life cycles is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Understand how the movement of a source of waves relative to an observer/detector gives rise to a shift in frequency (Doppler effect).

Use - doppler effect to connect the rule to the data and decision in the question.

This matters because - doppler effect determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply - doppler effect to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: - Doppler effect is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Use redshift z = Δλ/λ ≈ −Δf/f ≈ v/c for a source moving relative to an observer, and Hubble's law v = H0d for cosmological distances.

Use - redshift and hubble’s law to connect the rule to the data and decision in the question.

This matters because - redshift and hubble’s law determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply - redshift and hubble’s law to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: - Redshift and Hubble’s law is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Understand the controversy over the age and ultimate fate of the universe associated with the value of the Hubble constant and the possible existence of dark matter.

Use - age and fate of the universe to connect the rule to the data and decision in the question.

This matters because - age and fate of the universe determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply - age and fate of the universe to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: - Age and fate of the universe is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.