... I would assume that they are not as good unless they emit some super cosmic space rays that make your plants grow bigger
Cosmic background radiation is mainly composed of infrared radiation in the microwave range of the electromagnetic spectrum that are the thermal remnants of the Big Bang. Smaller numbers of gamma or X-rays with the occasional high-energy neutrino also bombard our planet frequently.. No known plant on earth responds to these wavelengths, rather they have evolved to take advantage of the visible wavelengths (Red Yellow Green Blue etc..) because the sun emits the visible spectrum in high concentration. Sorry for debunking your theory Creek!
Use the Sun to grow your dope whenever possible, if not MH or HPS are your best bet followed by CFLs because they have been proven to work time and time again.
If you are feeling adventurous, try a LED grow, but don't buy into the cheap ebay lights. Rather get or build a second-generation type, such as
"The penetrator" which has two frequencies each of blue and red high output LEDs, and some orange LEDs thrown in as well. LED grow lights are the future of our hobby because of their super-high efficiency, adjustable spectrum, marginal heat production, and decreasing cost, but many people are selling substandard systems that
will not grow a respectable crop. Do your research before buying anything!
