Investigate how astronomers sort galaxies, then earn your certificate.
Edwin Hubble was one of the most influential astronomers of all time. He set aside a career in law and, after serving in the military, turned to astronomy. He showed that the universe holds more than one galaxy, and that led him to sort galaxies into three groups by their shape.
Very common. They have bright centers with arms that wind outward, either loosely or tightly. Some have a bar of stars across the middle. Our Milky Way is a barred spiral.
Smooth and oval, a bit like an egg. They form few new stars, and some are enormous, hundreds of thousands of light-years across.
A little weird. They have no definite shape or structure. This is the group for shapes that fit nowhere else.
Score at least 80% on every mission to unlock your certificate. You can retry any mission.
Write two to four sentences in your own words. Use what you read in the briefing.
Move the sliders to change what your galaxy looks like. The classifier reads the shape the way an astronomer would. Complete the challenges on the right.
Pick a term on the left, then the description on the right that fits it. Wrong guesses lower your score.
Drag each galaxy card into the group that matches its shape. On a phone or tablet you can also tap a card, then tap a group. Look for arms, bars, smooth ovals, or no pattern at all.
Use the galaxies from your sort to answer these questions. Finish mission 4 first if you have not.
Claim: Galaxies are sorted by their ____, and the three main types are ____, ____, and ____.
Evidence: In the lab I saw that spiral galaxies ____. Elliptical galaxies ____. Irregular galaxies ____. For example, ____ was a ____ galaxy.
Reasoning: The evidence shows galaxies are grouped by ____ because ____. Irregular galaxies are the catch-all group because ____.
Score at least 80% on every mission to unlock it. Still needed: