1261

General Science / Re: How does crowdsourcing work in scientific projects?

« on: 02/11/2015 08:48:23 »

I guess crowdsourcing has always been used by scientific journals to peer-review papers submitted for publication.

There was recently another type of crowdsourcing scientific research in Australia.

The MOPRA telescope is mapping molecular dust clouds in the plane of the Milky Way. But the government decided not to fund them to finish the task they had set themselves.

So they appealed to the general public, and managed to raise enough money to finish their initially planned survey (and a little bit more). So they survive another year, and will start to map molecular dust clouds further outside the plane of the galaxy (hopefully detecting any that might be heading our way...). http://mopra.org/

Crowdfunding is a little different than traditional science grant applications (eg "What design will be print on the T-Shirts?" and "How much should we charge to 'name' a molecular gas cloud?").

Crowdfunding has been used by the Planetary Society to fund a pilot solar sail, and another project proposing a satellite looking for Near-Earth Asteroids is also looking for public funding.

I guess anything that inspires the public to dip into their pockets to help science is a good thing (and more productive than the horse race that will have most Australians dipping into their pockets tomorrow).

1262

New Theories / Re: Can the speed of light be faster than time itself?

« on: 02/11/2015 08:26:31 »

Thebox, are you saying that anything that travels faster than (1035) mph is travelling faster than time?

What does  travelling faster than time mean?

So it seems that this question is not about Einstein's relativity, but it's all about the speed of the Terminator: the day/night dividing line (not the time-traveling cyborg).

So with the deduction that the speed of the terminator at the equator is 1035 mph, this means you could get in a rocket, and travel faster than the terminator, and make the Sun "rise" in the west!

This has already been done. But they cheated, because at high latitudes, the terminator moves slower - and at the equinox at the North and South Poles, it does not move at all!

On one occasion, the Concorde supersonic passenger jet picked up passengers after their midnight New Years Eve celebrations in London, and delivered them to New York just in time to do it all again! They did not turn inside out, become frozen, become gods, or even zombies (although they may have felt like the latter the next morning).

In the extreme, a polar explorer could easily do a quick jog around the South Pole in 5 minutes, but its not like they will get any younger, or can change the future or anything.

1263

Chemistry / Re: Does burning candles improve air quality?

« on: 30/10/2015 23:50:53 »

Many smelly organic chemicals are flammable, so if they pass by a flame, they are likely to be broken down into non-smelly chemicals like H₂O and CO₂. However, they are also likely to  produce more noxious substances like NO_x and SO₂.

Incomplete burning of the wax can also create nanoparticles of soot, which may find their way deep into your lungs and cause irritation.

But if you are so familiar candles that you "like" the smell, or you find them "romantic", then you probably will overlook some of the negatives.

1264

Physics, Astronomy & Cosmology / Re: What is the largest possible rest mass of the photon?

« on: 30/10/2015 07:44:28 »

It is very hard to detect radio waves using an antenna which is much smaller than the wavelength. So in practice, it is hard to measure propagating radio waves with a frequency of < 1Hz, where the wavelength is larger than the Earth.

However, the Sun is effectively a low-frequency transmitter, producing 1 cycle of radiation from its solar magnetic field about every 22 years (approximately). The amplitude of this 22-year cycle is reflected in the 11-year sunspot cycle. However, due to the size of the Sun's magnetosphere, only a small fraction of the energy in this oscillating magnetic field would be released as freely-propagating EM waves.

1265

Physics, Astronomy & Cosmology / Re: Could you become a God by traveling at the speed of light?

« on: 26/10/2015 11:16:26 »

Imagine with me if we can move as fast as time what will happen, time will get slower and slower and when you reach to its speed times stops for you [/size][/font]
This seems to be talking about some type of time dilation.
I can see a couple of problems with this speculation:
- If you wish to make some changes in the frame of reference of Earth, moving very rapidly relative to Earth will make it appear to someone on Earth that time is moving slowly for you, and you are aging slowly.
- But from your viewpoint, everything is happening at the usual rate, so you aren't long-lived at all!
- From either frame of reference, if you are moving very rapidly, that gives you little visibility of what is happening on Earth, and little opportunity to change it in a controlled way.]

at the very least we can change the course of time

[/size]Time travel has always been a favorite topic of science fiction (some of them more serious than Terminator or Doctor Who), because then you can dream up all sorts of mayhem in which to engage.
[/size]
[/size]But so far, anything more than unidirectional time travel has remained out of our grasp; some claim that it is impossible, as it would violate the principle of Causality (which seems to be a good principle, in the absence of a time machine or faster-than-light warpdrive).

1266

Geology, Palaeontology & Archaeology / Re: When during human evolution did the first scientist appear?

« on: 25/10/2015 20:25:13 »

when chemical entropy changes near neurons and synapses new states of matter will appear that reflect this value.

In humans, neurons in the brain operate pretty much at 37C (if it diverges by more than a few degrees, you die).

When a nerve impulse propagates through a neuron, the temperature remains at 37C (because the brain has an effective liquid-cooling system).

No new states of matter appear because the temperature does not approach 0C (where ice could appear) or 100C (where steam could appear) or the air pressure on Mars (where steam could appear). The neuron operates in a liquid water environment.

The only change of state is the transient depolarization/repolarization change which propagates through the cell, plus possibly some more permanent adjustment in the synaptic linkage to adjacent nerves.

1267

Physics, Astronomy & Cosmology / Re: Do photons and massive particles behave the same in double slit experiments?

« on: 25/10/2015 03:22:50 »

Quantum effects have been demonstrated for particles as large as buckeyballs (C₆₀).

There is a claim that the dual-slit effect has been demonstrated on molecules having over 800 atoms.

1268

Physics, Astronomy & Cosmology / Re: is it possible to change the rotational speed of earth?

« on: 24/10/2015 02:10:52 »

Yes. The earthquake that destroyed Fukushima changed the rotation of the Earth by a measurable amount.

Less dramatically, Earth's tides are affecting the rotation of the Earth.

Humans are a long way from wielding the energies involved in all of Earth's tides or a large earthquake.

1269

Physiology & Medicine / Re: Why can't we remember everything?

« on: 24/10/2015 01:59:50 »

The human brain and sensory system has a very impressive form of data compression.

For example, to provide a video display that fills the human visual field with the maximum resolution of human vision would require somewhere around 2Gbps.

However, the processing in the back of the eyeball reduces this to an estimated 100kbps in the optic nerve. It is this compressed data stream that is processed by the brain to recognize people we know, and the child about to step in front of our car.

Similar processing occurs in our ears.

It takes previous experience to recognize these patterns - recognizing a mother's language and food appears to start before birth, and recognizing a mother's face and scent occurs in the first few months after birth.

The human brain does not store a video recording of these data streams, but integrates this with previously stored events. It is thought that this occurs by strengthening certain synaptic links, and weakening others. When we recall an event, our brain fills in the gaps with what "probably" happened, based on the sum total of our previous experiences.

These linkages are not permanent, but are revised every time we recall an event, and the memory can be changed by the context at the time we recall it. This undoubtedly saves a lot of neurones!

1270

Physics, Astronomy & Cosmology / Re: If an object is moving through space and no force is applied, where does it go?

« on: 21/10/2015 11:34:08 »

is it true that an object set into motion in outer space will travel in a straight line until a force alters it's direction?

One aspect that has not really been addressed: When you are near a massive object like the Earth or the Sun, gravity provides a force that attracts the two, changing both their paths. (Although the change in motion of the Sun would be very small and hard to measure for any object smaller than a planet.)

take that cannon ball up to the space station, and just 'shove' it off into space... it would just keep traveling in a straight line.

The space station is in orbit around the Earth, taking about 90 minutes to go around once. The Earth's gravitational field bends the path of the space station into a circle.

If you shove a cannonball off the space station, the cannonball will also be in orbit around the Earth, also taking about 90 minutes for one complete circuit.

If you gave it a really big shove (with a powerful rocket), you could take it out of Earth orbit, and into orbit around the Sun. It would take about 1 year for an orbit around the Sun.

from what I now understand the atmosphere in space wouldn't offer any resistance to the ball

The very thin atmosphere at the height of the ISS does provide some drag, causing it drop in altitude every month. To avoid the ISS crashing back to Earth while it is still in use, they use a rocket to boost its height every month or so.

A solid cannonball is denser than the hollow ISS, so it would take longer to crash, but it would eventually hit the thicker part of the atmosphere, forming a little fireball as it plummeted towards Earth.

1271

Physiology & Medicine / Re: Could you urinate on the moon?

« on: 18/10/2015 21:50:05 »

Given that water is a pretty scarce resource over most of the Moon, peeing into the Solar wind would be a bad move for anyone planning a long-term stay.

1272

Technology / Re: Can a powder make a powerful magnet?

« on: 14/10/2015 21:41:19 »

Neodymium magnets are quite strong, and they are formed from a powder which is rapidly cooled - the temperature is dropped by millions of degrees per second to "freeze in" a metastable structure. Obviously, this cooling does not continue for anywhere near a second!

Then a strong external magnetic field is applied while slowly cooling the material down through the Curie temperature, "freezing in" the external magnetic field in the orientation of the atomic-level magnetic fields.

As for attracting objects from several meters away, the mass and friction of an iron or other magnetic object would prevent it moving closer to the magnet, unless it were mounted on an air-hockey puck. It would probably work OK in the International Space Station, in a microgravity/microfriction environment.

You really need a superconducting magnet to attract objects from meters away in Earth's gravity. Some types of superconducting wire are manufactured from a powder, but the magnetic field is generated by the supercurrent, not by the wire itself.

See:

...but do not try this when you go for an MRI!

1273

General Science / Re: How would you operationalize Authority?

« on: 12/10/2015 21:24:03 »

If you need to do an experiment, you could google previous work in Psychology on the subject of Authority (referring to a few relevant papers in your report shows that you did some homework).

Then extend their work into a new area (perhaps one relevant to you, or in your locality).

A quick search turned up a questionnaire on Parental Authority - but there are many kinds of authority.
http://www.tandfonline.com/doi/abs/10.1207/s15327752jpa5701_13

I was recently talking to a psychology student who was able to engage many people to take part in his thesis study by connecting with them on social media, and pointing them to his questionnaire on-line. Tools like Survey Monkey are free, and will collect the results for you.

1274

Physics, Astronomy & Cosmology / Re: Quark gluon plasma what next ?

« on: 12/10/2015 11:04:28 »

You need really high energy colisions to generate a quark-gluon plasma with high-mass byproducts like quarks (which quickly dissipate into jets of other particles).

Other high-mass particles that you might get in high-energy colisions would include Higgs particles and strange quarks. But since the Higgs particle completes the standard model, I don't think you will get even more energetic particles within the standard model.

What you may get is different phases of quark-gluon plasma - a high viscosity liquid, a low viscosity liquid, a gas state, or even a "glassy" state. At extremely high energies (beyond current capabilities), it may even be possible to obtain "free" quarks.

By coliding heavy particles (eg lead nuclei instead of protons) at even higher energies, the renovated LHC will be able to generate denser and hotter plasmas. Some physicists hope that the LHC might just be able to create a micro black hole - but it will only be possible if some assumptions hold about string theory and higher dimensions (ie ideas outside the Standard Model).

1275

Geology, Palaeontology & Archaeology / Re: What does the discovery of Homo Naledi in a cave tell us about them?

« on: 05/10/2015 21:39:17 »

These are all questions that the investigators will be asking. Based on brief descriptions I have heard, it sounds to me like:

deep dark cave

It would have been impossible to maneuver a body through the tortuous path that the discoverers followed (and extremely difficult for even a cooperative live human).

I expect that in the past, there was a shorter access tunnel to the outside, which has now collapsed.

The lack of disturbance by wild animals suggests that the entrance was intentionally blocked, to keep animals out.

they were herded into the cave by another Homo

Based on the estimated number of skeletons in a small space, it was used for disposal of corpses, which was carried out over a long period of time.

command of fire?

The researchers have taken scrapings from the cave walls, and will be looking for evidence of soot.

1276

Marine Science / Re: Why is ocean marine life more colorful than in lakes?

« on: 12/08/2015 09:36:59 »

as colorful like those ocean fish in National Geographic

I'm sure that the fish in National Geographic are not a random sample!

1277

Cells, Microbes & Viruses / Re: How do probiotics survive stomach acid exposure?

« on: 28/07/2015 11:52:07 »

There are hints that newborns have a very different environment in their guts, which allows them to pick up antibodies from mothers milk, without actually chopping them up into their constituent amino acids, as an adult digestive system would.

Presumably, this milder environment would also allow them to pick up bacteria from people with whom they have close contact (especially the mother, during birth).

Some live bacteria are tolerant of the acid conditions in the stomach, although it would be a rare bacterium that could survive while passing through the acid conditions of the stomach, and then thrive in the more basic conditions further down the gut. However, some bacteria can enter a hardy spore stage, which would allow them to pass through these adverse environments, returning to active growth when they find conditions that better suit their lifestyle.

The unfortunate fact is that probiotics are limited to a small number of bacteria species that can be easily grown in a factory environment. In contrast, a healthy human micro biome contains many bacterial species which we can recognise from their genetic fingerprints, but currently have no way of growing in the lab, or of delivering to an appropriate ecological niche in the gut (short of a "poo transplant").

1278

Physics, Astronomy & Cosmology / Re: Has Time Rate Underground Compared to at the Surface Been Measured?

« on: 18/07/2015 04:49:26 »

Has an experiment been done to verify that time runs faster below ground than at the surface?

There have been many tests of gravitational redshift that have been done above ground, and in satellites. Some of the equipment is small enough to be used down a mineshaft, but I can't see a description of these experiments being done.

I think the result will be the opposite of what you expect.

Time runs slower the further you go down a gravitational well (as measured by a distant observer). So the centre of the Earth is the farthest down the Earth's gravitational well as you can go, and I expect that time will run slowest there.

1279

Physics, Astronomy & Cosmology / Re: If black holes stops time does white hole accelerate time?

« on: 14/07/2015 12:23:52 »

Strong candidates for black holes have been identified in the centre of many galaxies, and in supernova remnants; the general mechanisms that would lead to their formation and growth are well understood, and these conditions are thought to be fairly common throughout the universe.

"White holes" are a possible solution of Einstein's field equations. For now, white holes remain a purely hypothetical construct, with no candidates identified in the universe today, and no established mechanism which could create and maintain them.

There are suggestions that Hawking radiation from a black hole could represent a white hole, or that the Big Bang may represent a temporary white hole.

If white hole is the reverse of a black hole does it mean that inside the white hole time accelerates?

According to Einstein, time slows down near a concentrated mass (as measured by a distant observer). So time will be slower near a black hole (or, more subtly, near the surface of the Earth).

My understanding of the theory of white holes is that they are a concentrated mass. So my guess is that time will also slow down in the vicinity of a (hypothetical) white hole.

1280

Geology, Palaeontology & Archaeology / Re: What causes mass extinctions?

« on: 18/06/2015 11:15:45 »

any major consequences of really large objects striking the oceans?

Tsunamis can carry the energy of an impact thousands of miles from the point of impact within a few hours of the impact. This is more rapid than the slower dispersal of dust through the atmosphere, but would not reach very far into the centre of continents.

major impact events all refer to landing on the continents

I saw a theory that a large impact would leave a hole in the atmosphere - vacuum reaching the ground behind the descending meteorite. This would carry dust and rock from the impact out of the atmosphere into a suborbital trajectory, falling back into the atmosphere all over the planet for the next few hours.

Calculations suggested that the entire surface of the planet could be subjected to temperatures similar to a pizza oven for hours after the impact, leading to immediate global sterilisation of the surface.

Only plants and animals protected by a reasonably thick layer of soil or water would be able to survive these conditions, to emerge into a blighted and unrecognisable landscape.