Continental tropical air masses and thunderstorm formation in Texas

Earth Science

Air Mass

The Texas A&M University (1996-2007) claims that the Continental Tropical air mass is probably what's developing in the state of Arizona. These represent dry, hot air masses being created over southwest U.S. and north Mexico. The air mass makes its way into the U.S. via western Texas, New Mexico, and Arizona, and typically moves in the east to northeast direction, carrying dry, hot air to the state of Texas. The precipitation direly needed in summer months is often brought by the thunderstorms and rain showers that form.

Thunderstorms

As per the Texas A&M University's (1996-2007) explanation, a majority of thunderstorms take place during the evenings or late afternoons, following maximum warming by radiation. During late afternoons, instability will probably be at its peak, on account of daytime heating, which increases the PBL (planetary boundary layer)-middle layer temperature gradient. With occurrence of daytime heating, the capacity of the air to evaporate the water vapor content increases. Increased moisture facilitates higher instability levels and increased latent heat liberation.

Cold Fronts

Cold fronts arise when large cool-air masses come in contact with warm air masses, with the former advancing on the latter. Warm air is undercut by cooler air, and gets pushed upwards. A distinct line is formed by cumulonimbus clouds along the warm-cool air-mass boundary. With passage of a cold front, clouds will roll past and temperature in the atmosphere might drop noticeably. Stormy winds, rain, and the occasional thunderstorm may ensue with a cold front's passage (Texas A&M University, 1996-2007).

Black Holes

Black holes are spatial regions in which gravitational force is strong enough to prevent light from escaping. Powerful gravity arises due to compression of matter into a very small space. The compression may happen towards the last phase in the life of a star. A few black holes result from dying stars. As light cannot penetrate, one cannot see black holes (National Aeronautics and Space Administration (NASA), 2014).

Stars and Their Fates

NASA's (2014) general opinion is that with increase in size of stars, their lifespan decreases. Complete exhaustion of core hydrogen content of stars stops their nuclear reactions. The core collapses and heats up further. Hydrogen fuses in a crust about the core. Outer layers are pushed outwards, leading to expansion and cooling (Red Giant formation). For large-enough stars, more interesting nuclear reactions ensue, consuming helium and producing various heavier elements. However, gradually, the nucleus become progressively more unstable, and variations lead to pulsation and throwing off of outer layers. Their fate from here onward will depend on core size.

The Life of a Star

How stars die almost completely relies on its size (Holland & Williams, 2016). Stars with low mass live the longest, spending most of their lifetime in the 'main sequence' stage. With time, they simply cool to the White Dwarf/Black Dwarf stage. Their life is least violent. The sun and other stars of medium mass have roughly a fifteen-billion-year lifespan, with the initial two-thirds of their life spent in the 'main sequence' stage. After their hydrogen content exhausts, they burn helium, becoming red giants. Ultimately, they become unstable and their outer shells escape (planetary nebula), leaving 'White Dwarf' stars, which, ultimately cool down to 'Black Dwarf' stars. Largest mass stars live the shortest and are highly explosive. With time, they grow highly unstable, and transform into hypergiants/supergiants. Eventually, they rip apart into supernova, leaving behind neutron stars or black holes (Holland & Williams, 2016).

Terrestrial and Jovian Planets

The solar system's planets are either terrestrial (Venus, Earth, Mercury, and Mars) or Jovian (Saturn, Jupiter, Uranus and Neptune). The former have relatively small masses and sizes, with solid rocky exteriors, and metal-containing interiors. Being nearer in proximity to the sun, they are warmer compared to Jovian planets, which are cooler, heavier and larger, without solid surfaces. Sometimes termed as gas giants, Jovian planets mostly comprise of gases, with small quantities of rocky matter available deep within their cores (National Aeronautics and Space Administration, 2014).

Pluto's Demotion to 'Dwarf Planet' Status

The International Astronomical Union demoted Pluto to dwarf-planet status in 2006. Planets are celestial bodies orbiting about the Sun, with ample mass for their self-gravity for overcoming rigid physical forces to assume hydrostatic equilibrium (almost round) shape, clearing their orbit's neighborhood. While Pluto met one condition, the condition of 'clearing its neighborhood' (i.e., ejecting or 'vacuuming up' surrounding large objects) was pivotal. As Pluto's orbital space is shared with Kuiper Belt Objects, it was demoted to the dwarf planet category (National Aeronautics and Space Administration, 2014).