The reason for this is that ultraviolet light does not get through our Earth atmosphere, not even at the altitudes an airplane flies. The Hubble has made many discoveries in these areas of astronomy. The Hubble has been able to peer into deep space and see back into time, viewing the ancient universe as it was billions of years ago.
Infrared light is given off by less energetic processes in space in general.
The surfaces and atmospheres of planets and moons can be seen in the infrared too. Also clouds of gas will be seen which will give birth to new stars, and it will see the winds that will be springing up from stars just born. The chemical elements and molecules, like H2, CO, CO2, H2O, and the more exotic molecules will be seen floating in space clumped together into clouds by gravity. Milky Way Galaxy has been forming in the past and what it will be churning-out in the future. Sometimes these clouds hide interesting objects within.