Friday, November 3, 2017

In findings reported on Tuesday, an international team of astronomers discovered an exoplanet, called NGTS-1b, revolving around M-dwarf star NGTS-1, that the team said does not fit existing notions of how stars and planets form. NGTS-1b is a gas giant, similar to Jupiter and of comparable volume and mass, but its parent star is about half the diameter and mass of the Sun, making this the most massive planet orbiting an M-dwarf ever discovered.

NGTS-1b, about 600 light years from the Earth, is so extremely close to its star that a revolution around its star takes only about 2.6 Earth days — 2.647298 ± 0.000020 — and its surface temperature is about 800 K. The planet was discovered by observing periodic fluctuations in the star’s apparent brightness as NGTS-1b passed in front of it. NGTS-1b’s mass is less than Jupiter, about 0.812 MJ (mass of Jupiter), but it has greater volume, with radius about 1.33 RJ (radius of Jupiter). Its density was reported to be 0.42 g cm^-3 (with error: +0.59 to -0.28), meaning Jupiter, whose density is 1.326 g cm^-3, is likely around thrice as dense as the exoplanet.

“The discovery of NGTS-1b was a complete surprise to us,” said lead author Doctor Daniel Bayliss of the University of Warwick, in England. “[S]uch massive planets were not thought to exist around such small stars. This is the first exoplanet we have found with our new NGTS facility and we are already challenging the received wisdom of how planets form.”

The existing understanding of planetary formation, the team explained, says small stars can produce rocky planets but cannot pull in enough mass for larger, gaseous ones like NGTS-1b. Based on the observations, NGTS-1’s radius is 0.573±0.077 R? (solar radius) and using that value, astronomers calculated its weight to be about 0.598 M? (solar mass). The star’s density is almost ten times of the gas giant, 4.4 (with error: +2.4 to -1.4) g cm^-3. In comparison, the Sun’s density is 1.409 g cm^-3.

The research team discovered NGTS-1b using the Next-Generation Transit Survey (NGTS), an array of telescopes physically located in Chile, which was designed to search for planets around bright stars. NGTS-1 is a relatively dim red M-dwarf, which are very common in the universe, of apparent magnitude 15.52 ± 0.08. University of Warwick professor Peter Wheatley, who runs the NGTS, said, “NGTS-1b was difficult to find, despite being a monster of a planet, because its parent star is small and faint. Small stars are actually the most common in the universe, so it is possible there are many of these giant planets waiting to be found.”

To date, scientists have discovered only three gas giants which revolves around M-dwarf stars. The other two are Kepler-45b and HATS-6b which have masses 0.505 M_J and 0.32 M_{J respectively.}

Friday, January 20, 2006

A recently created Danish clothing company is selling on the internet T-shirts in order to support the clandestine radio station of the Colombian guerrilla group Revolutionary Armed Forces of Colombia (FARC) and the graphical workshop of the Popular Front for the Liberation of Palestine (PFLP). In fact the money will be used by these groups to carry on their terrorist activities. FARC activities include kidnappings, masacres, bombs, extortions and the drug trade.

Fighters and Lovers is selling the T-shirts at 170 DKK (US$27.6), from which 35 DKK (US$5.7) are to be destinated to support both armed groups.

Anna Duever, Fighters and Lovers PR chief, said to Spanish news agency EFE that their objective is to “defend freedom and social justice, which is FARC and PFLP are fighting for”. Duever believes the fact the FARC has been included by the EU in its terrorist group list is a “political game”. “We pay our taxes in Denmark, and that money is used for financing the troops our government has sent to Iraq. That’s terrorism. Besides, in Colombia there’s a regime oppressing population and torturing and killing its people”, she said.

Colombian Foreign Affairs Minister, Carolina Barco, said to local media that “financing terrorist groups is unacceptable and goes against all the international norms. Yesterday [Tuesday 19] our ambassador contacted the Danish government, we sent a protest note and have demanded an explanation.”

A year ago, a Danish NGO named Oprør (“Rebelion”) stated it had donated money to the Colombian guerrilla. A new antiterrorism law in Denmark may punish it.

Tuesday, March 22, 2005Between 10 to 15 of Bucharest’s 61 Unirii Boulevard residents will be able to connect to the Internet through their power lines. Starting from May of this year, a trial was organised by Electrica Muntenia Sud, the electricity company of Bucharest and Southern Romania.

The technology, known as Power Line Communications (PLC), enables the transmission of broadband Internet and fixed line telephony data through the existing electrical power network. The technology, in use by 13,000 people in 30 countries throughout the world, is considered very advantageous due to its high speeds and low cost. It uses infrastructure that is already available in most people’s homes.

Once the Unirii Boulevard trial concludes, and if it is successful, Electrica Muntenia Sud will roll-out the PLC Internet plan to the mass market. It is expected to be embraced by Romanians because its data transfer speed of 5Mps is available for a monthly subscription fee of less than 15 euro.

Bucharest is the first city in Southeastern Europe to trial such innovative technology.

Thursday, November 8, 2007

India is the latest of the countries where the One Laptop Per Child (OLPC) experiment has started. Children from the village of Khairat were given the opportunity to learn how to use the XO laptop. During the last year XO was distributed to children from Arahuay in Peru, Ban Samkha in Thailand, Cardal in Uruguay and Galadima in Nigeria. The OLPC team are, in their reports on the startup of the trials, delighted with how the laptop has improved access to information and ability to carry out educational activities. Thailand’s The Nation has praised the project, describing the children as “enthusiastic” and keen to attend school with their laptops.

Recent good news for the project sees Uruguay having ordered 100,000 of the machines which are to be given to children aged six to twelve. Should all go according to plan a further 300,000 machines will be purchased by 2009 to give one to every child in the country. As the first to order, Uruguay chose the OLPC XO laptop over its rival from Intel, the Classmate PC. In parallel with the delivery of the laptops network connectivity will be provided to schools involved in the project.

The remainder of this article is based on Carla G. Munroy’s Khairat Chronicle, which is available from the OLPC Wiki. Additional sources are listed at the end.