Kessler Syndrome, Epiphytes

The Kessler Syndrome is a term referring to the increasing space debris orbiting the Earth because of shrapnel from cataloged objects, namely from major satellite breakups. The term was coined by John Gabbard, a member of the North American Aerospace Defense Command (NORAD). After reading a paper by NASA scientist Donald Kessler about satellite collisions and its possible limitations to future satellite missions, Gabbard coined the phrase "Kessler Syndrome." In keeping with the implications of the organization he works under, Gabbard created the Gabbard diagram, a scatter plot charting the apogee and perigee of debris fragments against the orbital period. The Kessler Syndrome is meant to describe the dangers associated with the arbitrary collisions of cataloged objects, which causes a greater concentration of geocentric debris than that of the natural meteoroid concentration. The overall effect promotes positive feedback, an exponential growth of space debris as collisions become increasingly frequent due to the quantity of space debris already present. Today, data has been collected to support the prediction that the critical threshold has already been exceeded and collision cascading is a plausible long-term consequence. Debris has already exceeded the natural meteoroid count. The collision between the satellites Iridium 33 and Cosmos 2251 illustrate the Kessler Syndrome at work. The multiplication of space debris surpass that of atmospheric reentry rates, but the fortunate increase in solar activity and international orbital debris programs help to lessen the rate of debris collisions.

Epiphytes are autotrophs that grow on other plants but are not parasitic. They take water and nutrients from the air and the surrounding region. Epiphytic plants do not root in soil and thus are sometimes called "air plants." Epiphytes exhibit commensalism for they use other plants as physical supports but not as nutrient reservoirs, and so do not harm them. Many epiphytes reside in the hot, moist conditions present in the tropical rainforests. In this environment, epiphytes are typically found in the canopies where there is the most direct sunlight and a greater chance of pollination. Some epiphytes develop structures, such as cups or scales, that allow for the collection of rainwater. Thus, certain epiphytic plants may provide a small, watery ecosystem for small animals and insects. Epiphytic plants include ferns, bromeliads (e.g. pinapples), orchids, liverworts, mosses, and cacti. Lichen and algae are often considered epiphytic, but are not of the kingdom Plantae.