Sonoran Desert in the context of "Saguaro"

The Kitt Peak National Observatory (KPNO) is a United States astronomical observatory located on Kitt Peak of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono Oʼodham Nation, 88 kilometers (55 mi) west-southwest of Tucson, Arizona. With more than twenty optical and two radio telescopes, it is one of the largest gatherings of astronomical instruments in the Earth's northern hemisphere.

Kitt Peak National Observatory was founded in 1958. It is home to what was the largest solar telescope in the world, and many large astronomical telescopes of the late 20th century in the United States.

The international boundary separating Mexico and United States extends from the Pacific Ocean to the Gulf of Mexico. The border traverses a variety of terrains, ranging from urban areas to deserts. It is the most frequently crossed border in the world, with approximately 350 million documented crossings annually. Illegal crossing of the border to enter the United States has caused the Mexico–United States border crisis. It is one of two international borders that the United States has, the other being the northern Canada–United States border; Mexico has two other borders: with Belize and with Guatemala.

Four American Sun Belt states border Mexico: California, Arizona, New Mexico and Texas. One definition of Northern Mexico includes only the six Mexican states that border the U.S.: Baja California, Chihuahua, Coahuila, Nuevo León, Sonora and Tamaulipas. The total length of the continental border is 3,145 kilometers (1,954 miles). From the Gulf of Mexico, it follows the course of the Rio Grande (Río Bravo del Norte) to the border crossing at Ciudad Juárez, Chihuahua, and El Paso, Texas. Westward from El Paso–Juárez, it crosses vast tracts of the Chihuahuan and Sonoran deserts to the Colorado River Delta and San Diego–Tijuana, before reaching the Pacific Ocean.

The Fauna (pl.: faunae or faunas) is the whole of animal life present in a particular region or time. The corresponding terms for plants and fungi are flora and funga, respectively. Flora, fauna, funga and other forms of life are collectively referred to as biota. Zoologists and paleontologists use fauna to refer to a typical collection of animals found in a specific time or place, e.g. the "Sonoran Desert fauna" or the "Burgess Shale fauna". Paleontologists sometimes refer to a sequence of faunal stages, which is a series of rocks all containing similar fossils. The study of animals of a particular region is called faunistics.

Thermal lows, or heat lows, are non-frontal low-pressure areas that occur over the continents in the subtropics during the warm season, as the result of intense heating when compared to their surrounding environments. Thermal lows occur near the Sonoran Desert, on the Mexican Plateau, in California's Great Central Valley, in the Sahara, in the Kalahari, over north-west Argentina, in South America, over the Kimberley region of north-west Australia, over the Iberian Peninsula, and over the Tibetan Plateau.

On land, intense, rapid solar heating of the Earth's surface causes the heating of the lowest layers of the atmosphere, via re-radiated energy in the infrared spectrum. The hotter air is less dense than surrounding cooler air and rises, leading to the formation of a low-pressure area. Elevated areas can enhance the strength of the thermal low because they warm more quickly than the atmosphere which surrounds them at the same altitude. Over water, instability lows form during the winter when the air overlying the land is colder than the warmer water body.

The Dark Energy Spectroscopic Instrument (DESI) is a scientific research instrument for conducting spectrographic astronomical surveys of distant galaxies. Its main components are a focal plane containing 5,000 fiber-positioning robots, and a bank of spectrographs which are fed by the fibers. The instrument enables an experiment to probe the expansion history of the universe and the mysterious physics of dark energy. The main DESI survey started in May 2021. DESI sits at an elevation of 6,880 feet (2,100 m), where it has been retrofitted onto the Mayall Telescope on top of Kitt Peak in the Sonoran Desert, which is located 55 miles (89 km) from Tucson, Arizona, US.

The instrument is operated by the Lawrence Berkeley National Laboratory under funding from the US Department of Energy's Office of Science. Construction of the instrument was principally funded by the US Department of Energy's Office of Science, and by other numerous sources including the US National Science Foundation, the UK Science and Technology Facilities Council, France's Alternative Energies and Atomic Energy Commission, Mexico's National Council of Science and Technology, Spain's Ministry of Science and Innovation, by the Gordon and Betty Moore Foundation, by the Heising-Simons Foundation, and by collaborating institutions worldwide.

The Tohono Oʼodham Nation is the collective government body of the Tohono Oʼodham tribe in the United States. The Tohono Oʼodham Nation governs four separate sections of land with a combined area of 2.8 million acres (11,330 km), approximately the size of Connecticut and the second-largest Indigenous land holding in the United States. These lands are in the Sonoran Desert of south central Arizona and border the Mexico–United States border for 74 miles (119 km). The Nation is organized into 11 local districts and has a tripartite system of government. Sells is the Nation's largest community and functions as its capital. The Nation has about 34,000 enrolled members, most of whom live off of the reservations.