Category Science

HOW DID THE UNIVERSE BEGIN?

Although nobody can be sure how the Universe began, most scientists believe that it was horn from an enormous explosion 13 billion years ago. This explosion, called the “Big Bang”, was the point where space and time came into existence and all of the matter in the cosmos started to expand. Before the Big Bang, everything in the Universe was compressed into a minuscule area no bigger than the nucleus of an atom. The Big Bang was an unimaginably violent explosion that sent particles flying in every direction. A process called cosmic inflation caused the Universe to expand into an area bigger than the entire Milky Way in less than a second. Moments later, the temperature began to decrease, and the Universe began to settle down. Stars and galaxies began to form roughly one billion years after the Big Bang.

Initially, the universe was permeated only by energy. Some of this energy congealed into particles, which assembled into light atoms like hydrogen and helium. These atoms clumped first into galaxies, then stars, inside whose fiery furnaces all the other elements were forged.

This is the generally agreed-upon picture of our universe’s origins as depicted by scientists. It is a powerful model that explains many of the things scientists see when they look up in the sky, such as the remarkable smoothness of space-time on large scales and the even distribution of galaxies on opposite sides of the universe.

But there are things about this story that make some scientists uneasy. For starters, the idea that the universe underwent a period of rapid inflation early in its history cannot be directly tested, and it relies on the existence of a mysterious form of energy in the universe’s beginning that has long since disappeared.

“Inflation is an extremely powerful theory, and yet we still have no idea what caused inflation or whether it is even the correct theory, although it works extremely well,” said Eric Agol, an astrophysicist at the University of Washington.

For some scientists, inflation is a clunky addition to the Big Bang model, a necessary complexity appended to make it fit with observations. This wouldn’t be the last addition.

“We’ve also learned there has to be dark matter in the universe, and now dark energy,” said Paul Steinhardt, a theoretical physicist at Princeton University. “So the way the model works today is you say, ‘OK, you take some Big Bang, you take some inflation, you tune that to have the following properties, then you add a certain amount of dark matter and dark energy.’ These things aren’t connected in a coherent theory.”

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WHAT DOES THE UNIVERSE CONTAIN?

The Universe contains quite literally everything — from you and me to the most distant stars. It is everything and anything that exists, occupying an unimaginably vast area. Distances in space are so immense that light from the furthest galaxies takes over 10 billion light years to reach Earth, even though light travels fast enough to go round the Earth several times every second. Everything that you can see in the night sky lays our Universe, from the Sun to far-off gas clouds like the Eagle Nebula (right).

The Universe is everything we can touch, feel, sense, measure or detect. It includes living things, planets, stars, galaxies, dust clouds, light, and even time. Before the birth of the Universe, time, space and matter did not exist.

The Universe contains billions of galaxies, each containing millions or billions of stars. The space between the stars and galaxies is largely empty. However, even places far from stars and planets contain scattered particles of dust or a few hydrogen atoms per cubic centimeter. Space is also filled with radiation (e.g. light and heat), magnetic fields and high energy particles (e.g. cosmic rays).

The Universe is incredibly huge. It would take a modern jet fighter more than a million years to reach the nearest star to the Sun. Travelling at the speed of light (300,000 km per second), it would take 100,000 years to cross our Milky Way galaxy alone.

No one knows the exact size of the Universe, because we cannot see the edge – if there is one. All we do know is that the visible Universe is at least 93 billion light years across. (A light year is the distance light travels in one year – about 9 trillion km.)

The Universe has not always been the same size. Scientists believe it began in a Big Bang, which took place nearly 14 billion years ago. Since then, the Universe has been expanding outward at very high speed. So the area of space we now see is billions of times bigger than it was when the Universe was very young. The galaxies are also moving further apart as the space between them expands.

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CAN WE PROVE THERE WAS A BIG BANG?

The idea of the “Big Bang” was first suggested in the 1920s by an astronomer named Edwin Hubble. He discovered that the Universe was expanding and suggested that it must have been much smaller in the past. The most convincing argument for the Big Bang lies in the presence of cosmic back-ground radiation. This is an echo of the energy released by the Big Bang, and was detected in 1965 by two astronomers. Scientists believe that the only possible source of this radiation is the dying heat of the Big Bang.

The Big Bang theory may be nice but it has to pass the judgment of observation. Nature and experiments is the final judge of the correctness of scientific ideas. Though some details of the Big Bang still need to be perfected, the general scheme of an early hot universe with a definite beginning is accepted by most astronomers today. Even so, we have to be open to the possibility that future observations could show it to be wrong. The observations given below are sometimes said to be “proof” of the Big Bang theory. Actually, the observations are consistent with the Big Bang theory, but do not provide proof. Recall from the discussion that scientific theories cannot be proven to be correct. As of now, the Big Bang theory is the only one that can explain all of these observations.

The galaxies (or galaxy clusters) are systematically moving away from us such that the farther away galaxies are moving faster away from us. As a result of General Relativity this means that space itself is expanding carrying the galaxies with it. Both the Big Bang Theory and its major competitor, the Steady State Theory, could explain it. Recall that the Steady State Theory used the perfect cosmological principle while the Big Bang uses the cosmological principle.

The cosmic microwave background radiation can be explained only by the Big Bang theory. The background radiation is the relic of an early hot universe. The Steady State theory could not explain the background radiation, and so fell into disfavor.

The amount of activity (active galaxies, quasars, collisions) was greater in the past than now. This shows that the universe does evolve (change) with time. The Steady State theory says that the universe should remain the same with time, so once again, it does not work.

The number of quasars drops off for very large redshifts (redshifts greater than about 50% of the speed of light). The Hubble-Lemaitre Law says that these are for large look-back times. This observation is taken to mean that the universe was not old enough to produce quasars at those large redshifts. The universe did have a beginning.

The observed abundance of hydrogen, helium, deuterium, lithium agrees with that predicted by the Big Bang theory. The abundances are checked from the spectra of the oldest stars and gas clouds which are made from unprocessed, primitive material. Even better observations are those made of light from very distant quasars that have passed through gas in regions of the universe where are no stars that could have contaminated the gas. The intervening intergalactic primordial gas imprints its signature on the quasar light giving us the composition of the primordial gas. All of those places have the predicted relative abundances.

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Thwarting insects and plant diseases

  •  Poison rose black spot with tomatoes

It’s long been known that roses grown next to tomatoes are less likely to fall victim to black spot. Make a fungicide by snipping tomato leaves from a plant and processing them in a blender with a little water; use enough leaves to make 2 cups (500ml) slurry. Combine with 1.5 litres water and 2 tablespoons cornflour and mix well. Store the solution in the fridge, marking it clearly with a warning label. Spray your rosebushes once a week with the fungicide.

  •  Repel caterpillars with onion juice

Spray cabbage and other vegetables that are targeted by caterpillars with onion juice and watch them take a detour. To make a spray, peel 2 medium-sized onions, grate them into a large bowl and add 4 litres water. Let the mixture sit overnight, then strain it into a spray bottle. To make the plants smelly enough to repel the pests, you may need to spray the leaves twice.

  • Soup-can stockades

To keep cutworms and other crawling pests from reaching newly planted seedlings, use soup cans as barriers. Cut the top and bottom out of a can, wash it well, then place it over a seedling. Twist it until the bottom is 5cm underground and your tender seedlings will gain protection from all directions. Paper cups with the base cut off can be used in the same way.

  • Fight fungus with bicarbonate of soda

Keep powdery mildew, black spot and other fungal diseases from infecting your fruit trees, vegetables, gardenias, roses, etc., with a bicarbonate of soda solution. In a large spray bottle, combine 1 teaspoon bicarbonate of soda, 1 teaspoon washing-up liquid and 1 litre warm water. Shake well and spray plant leaves and stems on both sides to discourage fungal diseases from taking hold.

Credit: Reader’s Digest

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The pleasure of the patio

  •  Bleach out pots

When repotting patio plants, sterilize flowerpots and planters to keep your precious newly purchased plants from succumbing to fusarium wilt or leaf curl. First plug the drainage holes with clay or putty. Then scrub off any caked debris with a scrubbing brush or toothbrush. Rinse the pots and fill with a solution of 1 part household bleach to 4 parts water. Let it stand for 2-3 hours. Discard the bleach in the laundry sink (not the garden), rinse the pots with fresh water and let them air-dry.

  • A bubble wrap warmer for camellias

Camellias grown in containers are particularly sensitive to the cold because of their shallow roots. When winter comes, wrap the camellia pot with thick plastic bubble wrap or several sheets of newspaper and secure the wrap with gaffer tape. Turn the pot so that the tape is out of the sight line of visitors.

  •  Polystyrene pellets as a drainage aid

Instead of putting rocks or pot shards in the bottom of a patio planter, fill the bottom quarter with the polystyrene pellets used for packing. What do they have over rocks? They make the planters lighter and allow you to use less potting soil.

  •  Plastic raincoats for exposed furniture

When heavy rain is forecast and you don’t have enough indoor space to bring your patio or garden tables and chairs inside, cover them with plastic dry-cleaning bags.

  •  Bubble away rust with vinegar and bicarb

If you have a concrete patio and metal furniture is leaving rust stains, try pouring full-strength white vinegar on the stains, top the puddle with a little bicarbonate of soda and leave it for about 10 minutes before wiping it off with an absorbent cloth. Older rust stains may need two or three more applications before they disappear.

  •  Wicker basket to hanging plant

Finally, here is a use for the wicker basket you have had stuck in the back of the cupboard for years. First use varnish to weatherproof the basket, then line the inside with a plastic garbage bag with a few drainage holes poked in it. Dig up four or five of the plants in your flowerbed, transfer them to the basket and you’ve made a hanging planter for the patio.

  •  Discourage mosquitoes

To stop mosquitoes and other insect larvae from breeding in birdbaths or water features, put a few drops of vegetable oil on top of the water. The oil spreads to form a film over the surface, ensuring that mosquito larvae won’t be able to breathe through the water’s surface. Renew the oil every week throughout summer.

  •  Herbal mosquito repellents

Steep a few pennyroyal or fleabane leaves in hot water and let them sit for 4-6 minutes. Strain the solution into a spray bottle and spray onto patio plants to repel mosquitoes. Or do the same with some garlic cloves. Simmer about 8-10 peeled garlic cloves in 2 cups (500ml) cooking oil for about an hour. Cool, strain into a spray bottle, then you’re right to spray away.

Credit: Reader’s Digest

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Successful strategies for insect pests

  •  Fool codling moths with fake apples

The larvae of these moths attack fruit such as apples and pears, but you can make sure that codling moths never lay eggs by luring them with fake apples — red Christmas tree balls hung in fruit trees. Start by threading a 30-cm loop of string through the ball holder, and then knot it two or three times. Spray the ‘apples’ on all sides with an adhesive insect spray and hang three or four on fruit-tree branches. The codling moths will home in on the red targets and get stuck.

  •  Bottle up wasps

Wasps follow their noses to sugar, so set them a sweet trap. Slice 7cm off the top of a large plastic soft-drink bottle and set it aside. Create a hanger by poking holes on either side of the bottom of the bottle, near the top. Thread 45-60cm string through the holes and triple-knot the ends. Place the cut-off piece with the neck attached into the bottle upside down to form a funnel and tape it tightly.

Pour sugar water into the bottle (use 4 parts water to 1 part sugar, dissolved) and hang your contraption on the branch of a tree that is frequented by wasps. Wasps trying to reach the liquid will be unable to escape from the bottle and then drown.

  •  Repellents in your herb rack

We love herbs and spices, but most garden pests find them unpalatable or even lethal. Sprinkle any of the following around your plants and watch leaf-hungry pests go elsewhere to dine.

  1.  Ground cinnamon
  2.  Ground cloves
  3.  Cayenne pepper
  4.   Black pepper
  5.  Chilli powder
  6.  Hot curry powder
  7.  Garlic powder
  8.  Dried lemon thyme
  9.  Dried bay leaves, crumbled.
  •  Repel aphids with aspirin

The active ingredient in aspirin, salicylic acid, is produced by plants as a natural protection — and that works to the gardener’s advantage. Experiments have shown that plants watered with a weak aspirin-and-water solution not only repel aphids and other sucking insects, but also promote strong plant growth.

To make a systemic solution, fill a bucket with 20 litres water and drop in 3 aspirin tablets. Stir until the tablets dissolve. Water plants as usual with the solution or pour it into a spray bottle to spray the plants’ leaves and stems on all sides. Thereafter, apply the aspirin water every two weeks.

  •  Send insects to a mothball chamber

If whiteflies, mealy bugs or other insect pests are attacking houseplants, then consider instituting death-by-mothball. Put an affected plant (pot, saucer and all) into a clear plastic dry-cleaning bag. Water the plant and drop 5-6 mothballs into the plastic bag.

Next, tie the bag closed with a twist tie, then move the bagged plant to a bright, though not directly sunlit, spot. Let it sit for a week before taking the plant from the bag and returning it to its usual place. If necessary, repeat the treatment until all of the pests have given up the ghost.

  •  Attract pests with warm colours

Paint milk cartons red, orange or yellow, coat with petroleum jelly or an adhesive insect spray, then put them at 4-m intervals in the garden. Flying insects will fly into them and get stuck. To kill aphids in particular, forgo the petroleum jelly and simply fill yellow container three-quarters full of water. The little green insects will zip straight to the container and end up in a watery grave.

  •  Let toads do it

Toads are among the most insect-hungry garden visitors. Attract them by placing a broken flowerpot or two in a shady spot, and then sink a dish filled with water and rocks into the soil so that any visiting toads will stick around.

  •  Get rid of squash vine borers with kerosene

You can prevent squash vine borers from attacking zucchini and pumpkins even before you seed these plants. Soak the seeds in kerosene overnight. The seedlings and mature plants will be able to repel borers — but the kerosene won’t infiltrate or affect the fruits.

  •  Eradicate earwig with vegetable oil

Earwigs are extremely partial to clematis, chrysanthemums, dahlias and gladiolus — so how do you give the hungry little creatures the brush-off? Not with a broom but with oil, an earwig favourite. Pour a pool of vegetable oil onto a saucer, leave it on the ground among your flowers and the earwigs will crawl into the saucer and drown.

  • Protective fabric-softener sheets

Keep mosquitoes from dive-bombing you as you work in the garden by tucking a few fabric-softener sheets into your clothing, or wipe the sheet directly onto your skin. Another great idea is to dab a little vanilla extract onto your pulse points and around your neck — it might be attractive to humans, but it will drive away the mosquitoes! Or, if you’re eating outdoors, put small bowls of water, with a squirt of lemon-scented detergent in them, nearby.

Credit: Reader’s Digest

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