WHAT’S OUR REACH?

If you started to travel, via a spaceship moving at 25,000 miles per hour, to Pluto when you were 25-years old, it would take you about 22 years to reach Pluto, and another 22 years to return. You would be 69 years old when you got back: a near-lifetime of travel, mostly surrounded by darkness. Most likely, this is not what you expected.

Only light, or other waves that have no intrinsic mass, can move at the speed of light. As an object (like a spaceship) approaches the speed of light, its mass rises ever more quickly, so that it takes more and more energy to speed it up further. It can never reach the speed of light, because by then, its mass would have become infinite, and by the equivalence of mass and energy (E = mc squared), it would have taken an infinite amount of energy to get there.

Thus, the science-fiction-generated fantasy (so prevalent in movies!) of humans traveling at the speed of light, from galaxy to galaxy, is not to happen!

THE VASTNESS OF SPACE

The universe consists of a million trillion trillion cubic light years and growing each second. [One cubic light year is enough to encompass our solar system]. 

Suppose you could select anyone of the cubic light years in space to explore, how would it look? 99 times out of a 100, you would find a pristine vacuum embedded in total blackness. Absolutely nothing would be visible to the unaided eye. The universe is almost entirely empty space. Galaxies, stars, and planets are scattered here and there in a lumpy way, not in a uniform way. 

Source: A manual written by me [circa 2010], for my college-level, introductory course for “Earth and Space Science for Liberal Studies Majors.” I taught this course for many years.

CORUNDUM: “IT’S ALL ABOUT THE COLOR”

The mineral corundum consists of crystalline aluminum oxide. Its hardness is 9, which is next to diamond at hardness of 10. Corundum’s crystals are hexagonal (six-sided), and they also leave no streak on a mineralogical “streak-plate test.” 

To most  people corundum is, indeed, “all about the color.” The two main varieties of corundum are: rubies, if the crystals are pink to blood-red corundum, and sapphires, if they are blue. Actually, the latter exhibits a wide range of colors depending on composition.

Pure corundum is colorless, but tiny amounts of impurities in corundum results in other colors: e.g., yellow to yellow brown, green, purple to violet [e.g., like some of those shown below], and even pure white.

Corundum occurs in metamorphic and igneous rocks, as well as alluvial deposits. It is found in many countries, especially Burma, Sri Lanka, Thailand, and India; as well as in North Carolina and Montana.

The pieces of rock containing purple to violet crystals shown here were found in a metamorphic muscovite schist in the San Gabriel Mountains, southern California. Some small rock samples were given to me by one of my students and, later, some other samples were given to me by one of my colleagues.

Figure 1. A piece (3.5 cm wide and 3 cm high) of muscovite schist containing small crystals of violet corundum. A weathered surface of this piece of rock is stained by iron and looks rusty to blackish. The crystals in this rock show parallel  alignment, caused by forces at the time of their origin.

Figure 2. Another piece of rock showing crystals of violet corundum.

                Figure 3. Several crystals of violet corundum in rock matrix.       

 Fig. 4. End and side views of extracted individual crystals of violet corundum. Crystal on the right is about 3 mm in length.

CACTI: GREAT DIVERSITY, BUT NO FOSSILS

The word “cacti” is the plural form of cactus. All cacti are spiny succulents. They are fleshy and store water. Importantly, they also have spines. Additionally, they are further characterized by having cylindrical to globular shape bodies.

[Note: there are also non-cactus succulents (e.g., “stone flowers”—see my previous post), which do not not have spines].

According to Duff (2017), there are 1750 recognized living species of cacti, and these species are further divided into 127 genera.

The timing of the origin of cacti has been speculated and grossly estimated as being Early Cretaceous, Eocene, or Oligocene, but these reports are very generalized (Griffith, 2004). Although Chaney (1944) and Duff (2017) reported on a single fossil cactus from Eocene rocks of the Green River Formation in Utah, their claims cannot be verified. 

To date, there is no substantiated fossil record of cacti. This is because they lack preservable mineralized tissue. Thus, they are unlike seashells, heavy vertebrate bones, or regular tree wood. What cacti do have internally, however, is much open space (voids) and lots of water. This so-called “wood” is commonly used in aquaria because the abundant “holes” in this cactus material provide places for fish to hide. Some representative examples of the "extremely porous"internal skeletons of cacti "wood" are shown below.

These figured pieces of "wood" are about three inches in diameter and four inches in height, except for the one on the lower right-hand corner--that piece of wood is about 2 inches in diameter and several feet in length.

PRICKLY PEAR CATCUS: GENUS OPUNTIA

This cactus goes by the moniker of “beaver tail cactus.” There are at least 100 species or so of this cactus, which is native to North and South America, and is especially common in the southwestern United States and Mexico. It has spread its distribution into the Mediterranean region, as well as Africa an Australia.

Cacti have rounded pads (also called cladoes, which are modified stems, are not leaves). Many species have a “fuzzy appearance,” because of the numerous spines on the surface of the pads. The length of its spines and their spacing are quite variable among the different species. It is a perennial plant, with new segments (rounded pads) emerging from, and branching off, from old pads (Fig. 2); thereby, producing a characteristic stacking pattern.

Figure showing cladoes (the biggest one is about 7 inches in length) of a prickly cactus.

Determination of the various species of the prickly pear cactus is difficult because of the hybridization among these species. This cactus can grow up to 15 feet tall (4.5 m), but most are three to eight feet tall.  

The prickly pear flowers bloom in late spring to early summer, and they can be yellow, orange, pink, or red in color. Bees and hummingbirds are attracted to these flowers. The fruit of the prickly pear cactus is edible.

Shown here are a few prickly pear flowers that bloomed in early May. This image was taken in mid May, 2025.

GOLDEN BARREL CACTUS: GENUS FEROCACTUS

Ferocactus acanthodes is an unbranched, slow-growing cactus that can live up to 30 years, with “oldtimers” reaching up to 2 meters tall. It is very efficient at storing water in its body. Also, Ferocactus acanthodes cactus is heliocentric as it can lean toward the sun. 

This specimen is slightly bigger than a basketball.

OLD MAN CACTUS: GENUS CEPHALOCERUS

Cephalocereus senillisis also referred to as the “Bunny Cactus” or the “White Persian Cat” cactus because of the fuzzy, white coatings on its spines. This Central American perennial cactus, which is cultivated in the USA, can be up 49 feet tall. 

Image of an "Old Man Cactus" about 4 feet tall in total height.

SAGUARO CACTUS: GENUS CARNEGIEA

Carnegiea gigantea is the only species belonging to this genus. This cactus is tree-like (up to 40 feet tall; note: these very slow growing giant-sized saguaro are called “Cardon” cactus. They can have a long life span, up to 150 years. Their arms start to grow around 75 to 100 years of age, but some never grow arms (these straight sided-specimens are called “spears.” Saguaro cacti are native to the Sonoran Desert in Mexico (including, based on my personal observations, some parts of Baja California Sur, Mexico.) Saguaro also occur in southern Arizona, southern California (Whipple Mountains), and in Sonora (Mexico) (Wikipedia, 2025).

Figure 8. An immature (at least 20 years old) saguraro cactus living in a front yard of one of my neigbor’s yard in northern Los Angeles County, southern California. [This is rather far north for this cactus].

This example of a saguaro cactus is about 8 feet tall. The horizontal white area near the top of the photo is a gutter on the side of a house.

References Cited

Chaney, R.W. 1944. A fossil cactus from the Eocene of Utah. American Journal of Botany 31(8):507-528.

Duff, R. 2017. the naturalhistorian.com   

https:/the naturalhistorian.com > 2017/07/12 > cacti-bi

Wikipedia. 2025.

A SUCCULENT THAT LOOKS LIKE A ROCK

Succulents are plants with parts that are thickened, fleshy, and engorged. They do not have spines. The word “succulent” is derived from the Latin word sucus, meaning juice or sap. [Note: succulents do not constitute a formal taxonomic category]. 

An interesting and unusual example of a succulent is Pleiospilos nelii mesembs, commonly known as the “split rock” succulent. It resembles a rounded fractured stone that is about 4 inches tall and 8 inches wide. This kind of succulent is commonly referred to as a “living stone.” In the fall, it blooms with a flower consisting of many light-orange petals, or in some varieties, with orange-white-magneta color. As this succulent grows, it will open slightly and eventually widen its “split area” to allow new growth.

Figure 1. Three views of the same individual Pleiospilos mesembs (a stone plant) (width 34 mm, height 30 mm, [equivalent to about 1.5 inches wide and 1.25 inches high].

Kingdom Plantae

Family Aizoaceae  [according to some experts, the family is Mesembryanthemaceae]

Genus Pleiospilos (there are several species)

Species nelii

Subspecies mesembs

Please remember that Pleiospilos is a succulent but not a cactus! Cacti are succulents characterized by having spines.

THE GREAT HORNED OWL

Bubo virginianus, a large-size owl can be up to 25 inches in length, has a wing span of up to three feet wide; with females being somewhat larger than males (Wikipedia, 2025). It has widely spaced ear tuffs, and its body feathers are mottled brown above, lighter below.

Two views of the same Great Horned Owl observed in northern Los Angeles County, Southern California.

It is native to the Americas, from 68 degrees latitude north to 54 degrees south): including North America [but not north of the high Arctic tree line], Central America, and to the Straits of Magellan in Chile in South America. It can live in forests, wetlands (including marshes and mangroves), deserts, and urban areas. It prefers scrub areas, woodlands, deserts, canyons, and bottomlands. The northern population may migrate south during winter months. And this owl can live at elevations from sea level to 11,000 feet in elevation. It can live in hollow trees, caves, rock ledges, abandoned nests of other birds, or even man-made structures.

They live to be about 28 years old in the wild and up to 50 years in captivity. 

They can fly as fast as up to 40 mph. They have giant cat-like eyes that do not move but can see in shades of black, gray, and white. Some have limited color vision. Females are larger than males, but males have a deeper sounding hoot. They can hoot all night to solidify their pair bonding (they general mate for life). They are most active at dawn and dusk. They can carry up to 10 pounds of weight.

The can attack any medium-sized mammal. Their talons can exert great pressure, enough to severe the spine of their prey. 

Their call is: "hoo, hoo-hoo, hoooo-ho"; the male’s pitch is higher than that of the female. 

Active at dawn and dusk + night; they sleep during the day. Thus, they are rarely seen; and also because of their excellent camouflage.

They live for 20 to 30 years.

GEOLOGIC RANGE OF OWLS: Their earliest geologic occurrence (a few bones) of owls, is a single species of Ogygoptynix, of late Paleocene (Mayr, 2002). A few bones of Eocene owls are also uncommon. Barn Owl dates back to the Miocene (25-20 million years ago (Wikipedia).

GEOLOGIC RANGE OF THE GREAT HORNED OWL: Fossil bones of late Pleistocene Bubo virgianus have been found at Rancho La Brea Tar Pits in southern California (Madan et al. 2019).  

ACKNOWLEDGMENT:

The owl shown here was seen and photographed by my youngest daughter, in the morning during mid-April, in northern Los Angeles County, southern California. Sightings at that time of day one are rare!                                          

REFERENCES CITED

Madan and two others. 2019. Stasis in the smaller owls from Rancho La Brea during the last glacial-interglacial climate change. Palaeontolgia Electronic 22.3.70, pp. 1-12.

Mayr, G. 2002.A  owl from the Paleocene of Walbeck, Germany. Mitt. Mus. Nat.kd. Berl. Geowiss 5, pp. 283-288. (pdf available online for free). 

North America Wildlife---Reader’s Digest.

Wikipedia. 2025.

WHITE-CROWNED SPARROW, NORTHERN LOS ANGELES COUNTY, CALIFORNIA

Lately, I ventured into observing and recording a diverse range of aquatic birds living in northern Los Angeles County, southern California (see one of my recent blogs), but I held off researching terrestrial birds. Yet, the latter are a treasure right before my eyes. So, stay tuned to my blog! Who knows what species of animal or plant will turn up next! 

Having diverse flower gardens, in both front and back yards of my home, has made them “bird havens.” Plus, we have a sturdy hedge in the front yard, and a tall brick wall in the back yard. These provide some protection against wandering predators. Such a yard stands out in glaring contrast to most other homes in my neighborhood. Mostly, they are usually nothing more than the standard grassy yard ± a few shrubs and/or a few flowers.

I could no longer ignore some small birds that regularly visit, early every morning, the garden in my front yard. These birds are Zonotrichia leucophrys (Foster, J.R., 1772). This species, which is also known as the “white crowned sparrow” (Burton, 1999), “caught my attention” because of its striking head pattern of black and white stripes.

This species is just one of the very diverse group of western sparrows, which are native to North America and also widespread from Alaska through California, Baja California, and northern Mexico; but not along the eastern seaboard of the United States. This species is a common bird in southern California (Los Angeles area), Oregon, and Washington. For more details, go to https://www.allaboutbirds.org/guide/White-crowned_Sparrow/overview 

The west-coast population of this species of sparrow is stable and not threatened. This small bird (5.5 to 7 inches in length) is very active and does not stay in one spot for very long at all! It is difficult to get a photo of it. A small group (about 10 individuals) usually visits my garden every morning (March) and at the same time. They stay for only about a few minutes, quickly searching the ground for seeds, especially those shed by the adjacent borage plants (see one of my earlier posts about this plant). These small birds hop and flutter about so quickly that it is very difficult to take a photograph that is not blurred. I finally realized that I should just take a rapid succession of images and hope for the best. That worked OK, but the images are somewhat blurred when enlarged. Nevertheless, these images (as shown here) clearly show that the population of this bird that visits my garden is characterized by having has a central white stripe down the center of the head. These sparrows apparently migrated away by early April, and they have been replaced, in a much less way, by a few occasional but different sparrows with brown heads.

Also, if you are interested in seeing other photos of this species, I recommend the internet site, available (for free), at https://ebird.org > species > wchspa 

Fig. 1. A white-crowned sparrow in the garden in the front yard of my home.

Fig. 2. A white-crowned sparrow next to a borage plant in the same garden.

References:

Burton, R. 1999. The Audubon Backyard Birdwatcher. 329 pp.

ebird.org

7.fs1.hubspotusercontent-na1.net 

https://www.allaboutbirds.org/guide/White-crowned_Sparrow/overview