Most pictures of galaxies that you see, such as the beautiful images from the Hubble Space Telescope, are optical images. These are made using telescopes which detect light in the same wavelength range that our eyes see. However, scientists can design telescopes which use different parts of the electromagnetic spectrum, such as shorter-wavelength ultraviolet light or longer-wavelength infrared and radio emission.
The planet Vulcan? Hey, wasn't that just a made-up planet Gene Roddenberry created for Star Trek? Not at all, gentle reader. For a period of many years in the late nineteenth century, some, if not all, of the world's astronomer's believed in the existence of a planet Vulcan that orbited the Sun inside the orbit of Mercury.