Final answer:
For mapping the births of new stars, infrared wavelengths are most effective because they penetrate through the dense gas and dust in stellar nurseries better than visible light, allowing clearer observations of star formation.
Step-by-step explanation:
The births of new stars have been best mapped recently using infrared wavelengths. This is because regions where new stars form, often referred to as stellar nurseries, tend to have a high density of gas and dust. These materials can obscure the light from these regions at visible wavelengths. However, infrared radiation, which has longer wavelengths, can pass through the dust with much less attenuation, providing clearer images of the new stars. Furthermore, radio waves which also have long wavelengths, can pass unimpeded past the interstellar dust grains, making radio observations another method for studying these regions.
Consequently, for searching new star formations, infrared and radio observations are much more effective compared to ultraviolet, visible, or X-ray wavelengths. This is because the latter are more susceptible to being scattered or absorbed by the interstellar medium, which makes it difficult to detect the birthplaces of stars.