5.9Chapter 5: The Earth in Space

Using planetary data — Alhussan Physics - Stage 7 Revision Notes & Topical Questions

5 min read 9 parts Lesson 9 of 11 1 quiz

📚 Alhussan Physics - Stage 7 Hub / Topical Revision

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Lesson summary

Physics 5.9 Using planetary data — Day Length, Year Length and Axis Tilt — Alhussan International Academy — Physics (Stages 7–9) notes: Distinguish primary from secondary sources of data and use planetary data tables to answer questions.Data = observations or measurements recorde…

Primary source
Use in astronomy
Importance
Similar tilt
Small tilt
Large tilt

Part 1 of 7Primary and secondary sources

Data

Data observations or measurements recorded in an experiment

Recording

Recording scientists record data in tables and display them using charts or graphs

Primary source

Primary source experiments and fieldwork are primary sources, where you collect the data yourself

Secondary source

Secondary source a book or the Internet contains data that other people have collected

Use in astronomy

Use in astronomy questions about planets cannot be answered by experiments in a laboratory, so secondary data are used

Part 2 of 7Checking data

Importance

Importance data must be checked whether they are primary or secondary

Methods of checking

Repeat an experiment.
Look at more than one secondary source to check that the data are the same.

Part 3 of 7Day length and year length

1Day

Day the time a planet takes to spin once on its axis, which is 24 hours on Earth

2Year

Year the time a planet takes to go once around the Sun, which is 365 days (1.00 year) on Earth

3Question

Question the data can be used to find whether day length on other planets is related to year length

Part 4 of 7Spin time and orbit time of the planets

Planet	Time to spin once on its axis (hours)	Time to go once around the Sun (years)
Mercury	1416 (59 days)	0.24
Venus	244 days	0.69
Earth	24	1.00
Mars	25	1.88
Jupiter	10	11.86
Saturn	11	29.46
Uranus	17	84.01
Neptune	16	164.80

1Year length

Year length it increases from Mercury to Neptune, so planets further from the Sun take longer to go once around it

2Day length

Day length there is no simple relationship between the time to spin once and the time to go once around the Sun

Part 5 of 7Seasons and axis tilt

Cause

Cause seasons on Earth are due to the tilt of the Earth's axis

Tilt data

Tilt data the angle at which the axis of each planet is tilted can be found on websites and compared

No tilt

No tilt a planet with no tilt, such as Mercury (0°), has no seasons

Similar tilt

Similar tilt planets with a tilt close to the Earth's 23.5° have seasons similar to Earth's

Small tilt

Small tilt a planet with a small tilt, such as Jupiter (3.1°), has seasons that are hardly noticeable

Large tilt

Large tilt a planet with a very large tilt, such as Uranus (97.9°), has seasons very different from the Earth's

Part 6 of 7Axis tilt of the planets

Planet	Angle of tilt (°)
Mercury	0
Venus	177.4
Earth	23.5
Mars	24.0
Jupiter	3.1
Saturn	26.7
Uranus	97.9
Neptune	28.8

Retrograde spin

Venus (177°) and Uranus (98°) have tilts shown with a second angle of −3° and −82° in the diagram

Not to scale

Not to scale a diagram that is not to scale cannot show real sizes or distances

Part 7 of 7Presenting secondary data

Diagrams

Diagrams data are not always presented in a table, so numbers taken from a diagram can be put into a table

Re-displaying

Re-displaying secondary data may need to be shown in a different way, such as on a chart or a graph

Units

Units table headings should include units such as hours, days and years

Key terms

Term	Meaning
Data	Observations or measurements recorded in an experiment.
Primary source	Experiments and fieldwork, where you collect the data yourself.
Secondary source	A book or the Internet, containing data other people collected.
Day	Time for a planet to spin once on its axis.
Year	Time for a planet to go once around the Sun.
Axis tilt	Angle at which a planet's axis is tilted, which causes seasons.

Avoid these mistakes

Thinking a year is the time to spin once — a day is one spin and a year is one orbit.

Assuming data in a book are always correct — check more than one source.

Thinking a diagram that is not to scale shows real sizes or distances — it does not.

Thinking only experiments give data — fieldwork is also a primary source, and books and websites are secondary sources.

Last updated: 18 October 2026