Thus there are two unknowns (albedo and size), which can be determined by two independent measurements (of the amount of reflected light and emitted infrared heat radiation). TNOs are so far from the Sun that they are very cold, hence producing black-body radiation around 60 micrometres in wavelength. This wavelength of light is impossible to observe on the Earth's surface, but only from space using, e.g. the Spitzer Space Telescope. For ground-based observations, astronomers observe the tail of the black-body radiation in the far infrared. This far infrared radiation is so dim that the thermal method is only applicable to the largest KBOs. For the majority of (small) objects, the diameter is estimated by assuming an albedo. However, the albedos found range from 0.50 down to 0.05, resulting in a size range of 1,200–3,700 km for an object of magnitude of 1.0.
thus there are two unknowns (albedo and size) which can be determined by two independent measurements (of the amount of reflected light and emitted infrared heat radiation) tnos are so far from the sun that they are very cold hence producing black-body radiation around 60 micrometres in wavelength this wavelength of light is impossible to observe on the earth's surface but only from space using eg the spitzer space telescope for ground-based observations astronomers observe the tail of the black-body radiation in the far infrared this far infrared radiation is so dim that the thermal method is only applicable to the largest kbos for the majority of (small) objects the diameter is estimated by assuming an albedo however the albedos found range from 050 down to 005 resulting in a size range of 1200–3700 km for an object of magnitude of 10