Time Travel

What is time travel? Is it possible? Time travel is the concept of moving between different points in time in a manner analogous to moving between different points in space, either sending objects or information backwards in time to some moment before the present or sending objects forward from the present to the future without the need to experience the intervening period at the normal rate. It is quite a thought evoking topic and therefore I have decided to include it under Term 3's Physics topic on my Science E-Portfolio. Many believe that time travel is possible, as there is a scientific hypothesis that as long as an object would be faster than light, it could travel through time. However, Albert Einstein once said that “the speed of light was the traffic law of the universe.” This means that nothing can travel faster than light.  Is this true?

                The speed of light is approximately 186282 miles a second. It is supposedly the fastest of any matter, energy, or information known in the universe. Our modern day technology is constantly improving, and thus scientists have new means to try out such experiments, such as trying to make objects move at the speed of light, using advanced machinery.

Another supposed way of time travel is via wormholes. A wormhole is a hypothetical topological feature of space-time that would be, fundamentally, a "shortcut" through space-time. The theory of general relativity predicts that if traversable wormholes exist, they could allow time travel. This would be accomplished by accelerating one end of the wormhole to a high velocity relative to the other, and then sometime later bringing it back; relativistic time dilation would result in the accelerated wormhole mouth aging less than the stationary one as seen by an external observer, similar to what is seen in the twin paradox. However, time connects differently through the wormhole than outside it, so that synchronized clocks at each mouth will remain synchronized to someone travelling through the wormhole itself, no matter how the mouths move around. This means that anything which entered the accelerated wormhole mouth would exit the stationary one at a point in time prior to its entry. However, a wormhole is thought to have an extremely strong gravitational field, which will cause objects to compress into long thin shapes, which is also known as ‘spaghettification’. In the most extreme cases, such as these worm holes, the stretching is so powerful that no object can withstand it. It is thought that it may not be possible to convert a wormhole into a time machine in this manner; the predictions are made in the context of general relativity, but general relativity does not include quantum effects.

I have found in a news article, that Hong Kong physicists say they have proved that a single photon obeys Einstein's theory that nothing can travel faster than the speed of light, demonstrating that outside science fiction, time travel is impossible.

The Hong Kong University of Science and Technology research team led by Du Shengwang said they had proved that a single photon, or unit of light, "obeys the traffic law of the universe". They said on their website that Einstein claimed that nothing could go faster than light. Professor Du's study demonstrates that a single photon, the fundamental quanta of light, also obeys the traffic law of the universe just like classical electro-magnetic waves. The possibility of time travel was raised a decade ago when scientists discovered superluminal (faster than light) propagation of optical pulses in some specific medium the science team said. It was later found to be a visual effect, but researchers thought it might still be possible for a single photon to exceed light speed. Professor Du, however, believed Einstein was right and determined to end the debate by measuring the ultimate speed of a single photon, which had not been done before.

Quoted from them,

"The study, which showed that single photons also obey the speed limit c, confirms Einstein's causality; that is, an effect cannot occur before its cause," the university said.

"By showing that single photons cannot travel faster than the speed of light, our results bring a closure to the debate on the true speed of information carried by a single photon," said Du, assistant professor of physics.

"Our findings will also likely have potential applications by giving scientists a better picture on the transmission of quantum information."

Reflections:

I feel that this topic is indeed intriguing, as time travel is an extremely complex topic under physics, which is why I find it very puzzling yet interested to find out more because of this. I believe that although it seems impossible to travel through time even with today’s modern day advanced technology, it will become possible in the near-future when our future society’s scientists explore deeper into the secrets of light and wormholes and find out more important information which might aid us in finding a way to travel through time. Although our current scientists have yet to find a matter or energy which can travel at the rapid speed of light, or find a way to enter wormholes without getting spaghettified and instantly being stretched apart, I have high hopes for the future scientists and our future technology, and I believe that it is possible to travel through time in the future.

Earthquakes and Tsunamis

What is an earthquake? Why does it even occur when our ground is solid? Well, an earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. It is an important area in Physics, and therefore I have decided to include in under Term 3's Physics topic in my Science E-Portfolio. The seismicity or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time. Earthquakes are measured using observations from seismometers. The moment magnitude is the most common scale on which earthquakes larger than approximately 5 are reported for the entire globe. The more numerous earthquakes smaller than magnitude 5 reported by national seismological observatories are measured mostly on the local magnitude scale, also referred to as the Richter scale. These two scales are numerically similar over their range of validity. Magnitude 3 or lower earthquakes are mostly almost imperceptible and magnitude 7 and over potentially causes serious damage over large areas, depending on their depth. The largest earthquakes in historic times have been of magnitude slightly over 9, although there is no limit to the possible magnitude. The most recent large earthquake of magnitude 9.0 or larger was a 9.0 magnitude earthquake in Japan in March 2011, and it was the largest Japanese earthquake since records began. Intensity of shaking is measured on the modified Mercalli scale. The shallower an earthquake, the more damage to structures it causes, all else being equal. At the Earth's surface, earthquakes manifest themselves by shaking and sometimes displacement of the ground. Earthquakes can also trigger landslides, and occasionally volcanic activity. Earthquakes usually occur in neighbouring countries of Singapore as well, such as the recent Sumatra earthquake in Indonesia, which happened in 2007. Singapore faced tremors from this earthquake, and vibrations could be felt from structures built on artificial reclaimed land, such as One Raffles Quay.

What is a tsunami, then, and how is it related to an earthquake? When the epicenter of a large earthquake is located offshore, the seabed may be displaced sufficiently to cause a tsunami. It is derived from a Japanese term, which also means ‘harbour wave’.  Tsunamis are also known as tidal waves, and are extremely common in earthquake prone countries. They are caused by underwater explosions of any sort, be it volcanoes, bombs, meteorites or earthquakes.

A tsunami can be generated when the sea floor abruptly deforms and vertically displaces the overlying water. Tectonic earthquakes are a particular kind of earthquake that are associated with the Earth's crustal deformation; when these earthquakes occur beneath the sea, the water above the deformed area is displaced from its equilibrium position. More specifically, a tsunami can be generated when thrust faults associated with convergent or destructive plate boundaries move abruptly, resulting in water displacement, owing to the vertical component of movement involved. Movement on normal faults will also cause displacement of the seabed, but the size of the largest of such events is normally too small to give rise to a significant tsunami. A tsunami can be humongous, giving it its name as the ‘tidal’ wave. Tidal waves usually travel up to 700km/h and can rise as high as up to 30 metres as it approaches land, and apart from capsizing large ships, it can destroy structures on land and kills many people.

Reflections:

I feel that although earthquakes and tsunamis destroy our structures and kill many innocent lives, they are inevitable as they are part of nature, being natural disasters which come about naturally. I believe this is an interesting topic in physics, as it is amazing how an earthquake can cause a tsunami, such a large and titanic wave which causes much devastation even on land. These tidal waves can even bring down small buildings and tear down houses, as I recently saw in documentaries i=of the recent 2011 Japan earthquake and tsunami incident. Although this was extremely devastating and killed many and caused many to lose their homes in Japan, I am impressed by the Japan citizen’s calm reactions towards this shocking incident, and I feel that this is the way that everyone should react when facing such an incident, as such natural disasters are inevitable and neither can we blame nature for this happening. However, I am interested to find out more on such occurrences, as I am extremely intrigued by how earthquakes are formed, as it is an interesting part of physics, when the tectonic plates underground can shift and cause such massive destruction. Overall, I believe that earthquakes and tsunamis are extremely interesting, although deadly.

Cockroaches- Key to Future Antibiotics

While I was looking through some science magazines, there was an article about cockroaches going to be used in future antibiotics. Currently, British scientists hope that one of the hardiest insects around, the cockroach, may be used in future antibiotics. As they live in dirty and unhygienic environments, such as sewers and garbage dumps, they have developed a sort of immunity against bacteria over the years.
After going through tests, scientists have discovered that the tissue from the brains and nervous system of the cockroaches had killed more than 90% of the tested bacteria without damaging any human cells. The scientists were not surprised that the insects could naturally secrete their own antimicrobial drugs.
As cockroaches live in unsanitary and harsh environments, they often encounter many different types of bacteria. It would therefore be logical that they developed themselves against micro-organisms.
This topic interests me, as the thought of how an insect as dirty as the cockroach could be used in antibiotics to treat humans is shocking, yet the results of doing that would be very effective.