X-ray picture of
the Sun

Solar Images from the Yohkoh Satellite

These images come from the Yohkoh satellite, a solar observatory orbiting the Earth from 1991 to 2001.

Yohkoh detected the X-rays produced by the Sun's hot outer atmosphere. During most of 1992, Yohkoh also made visible (or "White Light") images of the Sun. We have provided White Light images stamped with the date and time of the observation; the date stamps have been left off of the provided X-ray images. The idea of this activity is to use what you have learned about magnetic active regions to match the X-ray pictures with the respective simultaneous White Light images. In this example, one White Light image is shown with three X-ray images. Can you tell which X-ray picture was taken on the same day as the White Light image? (Note: It may be easier to see the features on these images if you view them at full size. If you have a PC, right-click on the image and select "View Image". If you have a Mac, hold the mouse button down for a few seconds and then choose "View Image".)

White Light Picture
X-ray Picture 1
X-ray Picture 2
X-ray Picture 3

The White Light Picture shows two rows of spots, one just above the solar equator and another below. Which of the X-ray pictures has something similar? X-ray Picture 1 displays some activity on the far left-hand side, and another large active region just to the right of the center of the Sun's disk. X-ray Picture 2 displays a lot of activity on the far right-hand side of the Sun, and some more activity below and to the right of disk center. Only X-ray Picture 3 shows two rows of activity extending from left to right, which corresponds pretty well with the White Light Picture. If you said that X-ray Picture 3 was made at the same time as the White Light Picture, then you're right! Both were made on October 05, 1992.