Saturday, September 13, 2008

Galactic Internet' Could Broadcast Alien Signals

If we received a message from an extraterrestrial civilization, would we necessarily realize it? SETI has long scanned the skies for evidence of alien transmissions, while others have proposed a hunt for physical artifacts sent by our distant neighbors. But neutrino physicists at the University of Hawaii have proposed yet another possibility: that humans have already received an extraterrestrial communication, and that we might find the message in our existing observations of the stars.

Professor John Learned suggested that a civilization could attempt to initiate communication with other advanced civilizations by making unnatural alterations to Cepheids, relatively rare stars that other civilizations are likely to study:

Cepheids dim and brighten regularly, in a pattern that depends on their brightness. This lets astronomers measure the distance to the stars, helping to resolve mysteries such as the Universe's age and how fast it is expanding. As such, any sufficiently advanced civilization would want to monitor such stars, the scientists reasoned.

To send messages using a Cepheid, Learned and his colleagues suggest that extraterrestrials might change the star's cycle. A Cepheid becomes dimmer as ionized helium builds up in its atmosphere. Eventually, the atmosphere expands and deionizes, restarting the cycle.

Firing a high-energy neutrino beam into a Cepheid could heat its core and brighten the star early - "just as an electric pulse to the heart can make it skip a beat," Learned says.

Thus, the Cepheids might provide an intergalactic network of relays, which distant societies could use to broadcast messages to one another. But don't go warming up those neutrinos yet:

[T]he galactic internet would be slow - a Cepheid with a roughly one-day period could transmit about 180 bits per year. Such a transmission would require roughly a millionth of the star's energy, the researchers estimate.

For the time being, it makes more sense to comb through the 100 years' worth of data researchers have collected on the Cephids, searching for irregularities in the pulsing power. Learned estimates:

"Analyzing that data would take a graduate student a couple of months, and just think if it turned out to be correct."

At least the university's indentured academics know how they'll be spending their school year.

New experimental homes will heat themselves

The future might be in homes without
heating systems.
“We’ve learnt the lessons of the 1970s,” construction officials insist.

DENSITY, compactness and insulation are the current focus of architects and planners. New housing in Finland is being built more compactly than previously so that heating is more energy- and cost-efficient. Constructed in the right way, advocates maintain, compacter housing does not even require a heating system.

This sort of design is being experimented north of Helsinki in Tikkurila, Vantaa, where semi-detached houses are being built without a separate heating system.

The house will draw its heat primarily from the people, household appliances and lamps it contains. Jorma Vuoritsalo realises that, for many people, it’s hard to believe that a house’s contents alone could provide adequate heat, but he remains convinced that he won’t need to freeze in his new home.

Quite the opposite, according to Pekka Haikonen, director of development at Paroc, a company specialising in building insulation. He argues that, when built correctly, self-heating homes are perfectly pleasant since the internal temperature is self-regulating and heat is naturally distributed evenly. Paroc, along with the Technical Research Centre of Finland (VTT), is responsible for the design and execution of the Tikkurila development.

According to Paroc’s estimates, residents of the planned homes will face heating expenses of some 350 euros per year, whereas the annual bill incurred in heating the current average single-family house is closer to 1,200 euros. Even more strikingly, the energy consumed annually by one of the new experimental houses will be less than a sixth of that currently swallowed by a more conventional model.

An unpleasant flashback?

Compacter housing models are not an easy idea to market to Finns since they often provoke fears of poor air circulation and mould. Many have unpleasant memories of the houses built in response to the energy crisis of the 1970s, which were soon riddled with damp and mould-related damage.

But the lessons of the 1970s have been learnt, Helena Säteri reassures people. The director general of Finland’s environmental administration explains that the key is to ensure that air circulation in densely-built housing is both thorough and effective.

Pekka Rönkkö is also quick to calm fears of stuffy interiors. A product manager at Paroc, Rönkkö’s role as a technical expert on the Vantaa project has left him confident that every room in the new houses will contain fresh, well-circulated air.

Circulation won’t come in the form of an unpleasant draught, however, since air coming into the building will first be heated. Normally, this process will not require any power, since it will utilise the heat already inside the house.

When required, though, air entering the house can also be heated electrically. This may be necessary during winter following a period when the house has been empty and the internal temperature has fallen, when the family has returned from a winter holiday, for example.

Improving older buildings

Older houses are not easily modified in order to make them dense enough to go without a separate heating system, but they can certainly be made more energy-efficient, Rönkkö says. The key is to insulate them properly.

In particular, he encourages people to concentrate on insulating the building’s foundations, calling it a small but lucrative investment which fundamentally improves a house’s energy-efficiency and dramatically reduces annual electricity expenses.

Double glazing for the windows is slower to pay for itself long-term, he concedes, but remains a worth-while investment. Moreover, better-insulated windows reduce unwanted draught, which makes a house a much more pleasant place to live in.

Rönkkö also has a message for the housing cooperatives of apartment buildings: when renovating the building’s facade, it makes sense to improve insulation at the same time.

Maria Annala – STT