What is a galaxy ?

A galaxy is a group of stars, dark matter, nebulae and other astronomical objects. Most of them contain billions of stars and are tens of thousands of light years in diameter.

Galaxies are divided according to its shapes - elliptical galaxies (uniform), spiral galaxies (mostly thin disks with spiral arms) and irregular galaxies (with no definite structure).

Spiral galaxy centers around a focal point, which is generally spherical and bulges externally from the disks. The gravitational center of a galaxy is the hub, which is characterized by a massive black hole. Spiral arms surround the hub, which are grouped-up waves of gases and stars orbiting the center.

An elliptical galaxy has a large hub on the center but without the arms similar to the spiral galaxy. These galaxies feature yellowish to reddish stars. Irregular galaxies mostly have no distinct structure, but they often have distorted elliptical or spiral shape.

There are approximately a hundred billion galaxies in the universe. Most of these galaxies occur in huge agglomeration called “galaxy superclusters”. With the study of the spiral galaxies’ rotation, astronomers have discovered that most of the universal matter is not made up of gas or stars. Instead, it is made up of a dark matter, an invisible matter that still exerts gravity.

How can I protect my eyes while watching a solar eclipse ?

Regardless of age, a solar eclipse is an event worth waiting for, especially if you are very much fortunate to witness a total eclipse. However, direct eye contact with an eclipse may be dangerous for your eyes because the sunlight causes retinal damage. There are numerous ways to enjoy an eclipse without compromising your sight, ranging from using indirect observation with a pinhole camera to wearing glasses specifically made to protect your eyes while witnessing an eclipse.

Most of us are aware that looking directly at the sun can cause damage to our retina, and if you look at the sun long enough, this damage may lead to blindness. In an annular or partial eclipse, the sunlight is still dangerous enough to cause damage in our retina, but in a total eclipse, you can directly look at the sun but as soon as the eclipse makes even a little movement, it becomes a hazard.

You will need special glasses if you want to look directly at an eclipse. Eclipse glasses filter more of the sun’s ray than any regular sunglass. These glasses allow you to stare at the sun for several minutes. You can also use welding glasses to look directly at the sun during an eclipse. There are science stores where you can purchase eclipse glasses.

Another way to watch an eclipse is through a mirror. Cover most of the mirror’s surface, leave about an inch, and angle it in the eclipse projecting into a flat surface. This way, you will be watching the eclipse in projection. Remember to be cautious when using this process; you might accidentally flash the reflection of the eclipse in someone else’s eyes.

Lastly, you can watch an eclipse using a pinhole camera. You can create your pinhole camera by cutting a small hole in a piece of cardboard. Then, face the sun backward and hold your paper with hole over a clear sheet of white paper. Make some adjustments and you will see the sun’s image. You can move the top sheet to change the focus until you get a clear image of the sun.

What caused the evolution of primates to modern man ?

Approximately seven million years ago, the African apes or the common ancestor of humans and chimpanzees came into being. Sahelanthropus tchadensis or the African ape diverges from the rest of the great apes, including gorillas and orangutans. They all display different forms of communication and culture not only on their own tribe. They also show empathy and suggest theory of mind. Sahelanthropus tchadensis is the oldest hominin ancestor considered related to modern human.

Around three to five million years ago, ancestors of humans evolved from chimpanzees with the species called Australopithecus afarensis. The exact timeline is a little sketchy due to the little fossil evidence of chimpanzees. It is known that they live in rainforest environment where bones are not well preserved. Our ancestors moved and began to colonize plains about three million years ago. This migration triggered adaptation such as bipedalism. The first human to walk upright are the Australopithecus.

Homo habilis are the first genus homo member who uses tools; they lived about two to three million years ago. Using a one-sided stone as a tool in almost everything, lessen the load of their teeth that made the molars shrunk. Then, the game became scarcer and the spear throwing was developed. Some homo members are forced to migrate out of Africa about two million years ago.

One of the reasons that triggered human evolution was violence and sexual selection. If a band of early humans assaulted another band, killing all males and mating with all the females, their genes carries on to the next generation. It is vital not to have an idealistic view about the evolution of man, as it is not the way things actually work. The way we eat became less specialized as well, as we adapted to make full use of both gathering and hunting to get nutrients. 250,000 years ago, Homo sapiens appeared, capable of making advance tools and axes, allowing them to survive different kinds of environments and were able to scatter across the globe.

What are microbial insecticides ?

Microbial insecticides are a new type of pesticide that works by infecting insects with viruses, fungi, bacteria or amoeba. Although the safety of using microbial insecticides has been widely debated, some believing it to be a dangerous practice. The application of microbial insecticides is actually safer than other pesticides as each type of microbial insecticide only kills one particular species. As a result, it does not affect animal population, except interrupting the food chain by killing a certain insect in one area.

Bacterial microbial insecticides are used in different types of insects; one type is used in controlling crop-eating caterpillars, while another can be used in killing mosquito populations. Viral microbial insecticides usually work by initially making insects sick, then killing the particular insect species. The levels of results depend largely on the virus used. Amoebic insecticides typically do not kill insects, but forces them to reach sexual maturity or shorten their lifespan. Fungal microbial insecticides are usually used for cockroaches to spread a disease throughout its population.

Since microbial insecticides aim in killing a particular species, it is not effective in dealing with infestations involving several types of insects. Also, the effect of microbial insecticides are affected by outdoor elements like sun exposure, rains or snow. As such, spraying microbial insecticides before a heavy rain may reduce the effects and may not kill all insects in a given species.

Some environmentalists are concerned about the safety of using microbial insecticides. However, many of them prefer to use these kinds of insecticides, so that people can get rid of dangerous insects, while keeping beneficial insects existing in the environment.

How long will the universe last ?

The most accepted guess of modern cosmetologists regarding the earth’s existence is that it would last for a very long time, along the lines of a googolplex (1 followed by thousands of zeroes) years. Since people are afraid that the end of the universe means the end of human existence, this question has long been asked.

Since it is widely known that the universe continues to expand, current signs suggest that not only is the universe expands continuously, it is happening at a faster rate. Many experts report that the dark energy or the universe-wide pressure causes this occurrence.

The question of the universe’s lifespan is related to the overall geometry of the universe as it measures the overall density of the universe. If the density of the universe is more than omega, the universe is considered “close” with a spatial geometry. If the density of the universe is equal to omega, it is considered “flat” and the rate of expansion would slow down and approach zero in time. If the density of the universe is less than omega, it is considered “open” and the universe would expand indefinitely regardless of a presence of dark energy.

The current state of the universe is flat. Studies show that the universe would expand even with just enough dark energy. If the expansion continues for an indefinite period, stars, atoms, galaxies, local clusters and galactic super clusters would rip apart.

Which animals are smartest ?

Intelligence is defined as the ability of achieving complex goals within complex environments. Just like humans, some animals are more intelligent than others are. Octopuses have been called the most intelligent among invertebrates, while the intelligence of pigs and squirrels has also been studied. Below is a list of the smartest animals alive today:

1) Chimps – Chimpanzees have always been cited for their intelligence. Chimps make and use tools in acquiring foods. Studies have also shown that chimps have very sophisticated hunting methods that involve rank, influence and cooperation. Although they can be deceptive and manipulative, chimps can easily learn symbols, numbers and the human language. In fact, some chimpanzees have even outperformed college students in remembering numbers.

2) Great Apes (gorillas and orangutans) – Great apes have learned the basics of the American Sign language and even taught it to one another. They also performed basic computer functions that involved problems with colored shapes.

3) Cetaceans (whales and dolphins) – In the water, whales and dolphins reign as the smartest animals above any other aquatic animals. They can create mental images and communicate with fellow dolphins or whales, even at great distances using “songs”.

4) Elephants – Elephants have great memories and are capable of communicating over great distances. Like humans, elephants have death rituals and even grieve over their dead family members or companions.

5) Parrots – The only non-mammal animal considered as one of the smartest animals alive are parrots. They are capable of producing short comments and initiating conversations. A popular parrot named N’kisi has even learned 971 words and does not simply repeat what humans say, but also uses the word “know” five times in proper context.

6) Cats and dogs – The human’s favorite pet, cats and dogs, can understand a human’s emotions through tone of voice and facial expression. They can easily be trained to perform both simple and complex tasks such as potty training.

Studies are being conducted every year to learn animal intelligence and include more animals into this list.