Chart assignment
Charts to read and discuss
Read each chart, then answer its questions. Every chart shows its source and date; open it for a table of the numbers and the data to download.
Chart 1 of 2 · Space
How do astronomers find planets around other stars?
The interactive chart needs JavaScript. The numbers are on the chart's page.
As of November 2026, 4,785 of the 6,451 confirmed exoplanets, about 74%, were found by the transit method: a telescope sees a star dim slightly as a planet passes in front of it. Radial velocity, which spots a star's slight wobble as a planet tugs on it, found 1,204. Only 98 have been photographed directly (imaging).
Questions to discuss
- In one sentence of your own, what does this chart show?
- Find the biggest change or difference in the chart. What might explain it?
- Who collected these numbers, and how recent are they? What else would you want to know before drawing a conclusion?
Source: NASA Exoplanet Archive, Planetary Systems Composite Data (Public domain (NASA data); this research has made use of the NASA Exoplanet Archive, operated by Caltech under contract with NASA) · Data as of Nov 4, 2026
Open the chart and its numbersChart 2 of 2 · World
How much carbon dioxide does each country emit per person?
The interactive chart needs JavaScript. The numbers are on the chart's page.
In 2024, people in the United States emitted 13.6 tonnes of carbon dioxide each, in China 9.3 and in India 2.2, against 4.7 worldwide. The highest figure was 82.8 tonnes in Palau, then Qatar (47.3) and Bahrain (23.9). Search 203 countries and territories. The figures count carbon dioxide from burning fuel, industry and other sources, but not from changes in land use such as cutting forests; in a small country, a few power plants, refineries or fuel sales spread over few people can make the figure very high.
How to read this chart
Each bar is the carbon dioxide a country put into the air in a year, divided by its population, in tonnes per person. The dashed line is the world. A country can emit a lot in total but little per person if it has many people, and a tiny country with a refinery or power plant can top the list.
Questions to discuss
- Compare the United States, China and India. Which emits the most per person, and is that the one that emits the most in total?
- Why might some small countries have the highest figures on the chart?
- Which seems fairer for comparing countries' share of the blame for climate change, total emissions or emissions per person? Why?
Source: World Bank, World Development Indicators: Carbon dioxide (CO2) emissions excluding LULUCF per capita (t CO2e/capita) (CC BY 4.0 (credit the World Bank)) · Data as of Dec 31, 2024
Open the chart and its numbersTeachers: make your own chart assignment, or change this one. Free, no account needed.