Latest news with #KevinHeng
Forbes
15-07-2025
- Science
- Forbes
Why Bizarre Sub-Neptune Exoplanets Are So Crucial To Astrobiology
Artist's impression of a sub-Neptune planet. Most exoplanet hunters chase biosignatures the way bird dogs chase the scent of a quail. But in a talk at the European Astrobiology Institute's recent BEACON 25 conference in Reykjavik, astrophysicist Kevin Heng espouses the newfound notion of Geoastronomy. The idea is that the long road to finding signatures of life (biosignatures) on a planet beyond our solar system runs throughan epoch dominated by an interdisciplinary merger of Geology and Astronomy. The aim is to make sure that we first spectroscopically identify geological false positives in the atmospheres of extrasolar planets that are totally unlike those in our own solar system. These so-called sub-Neptunes are neither planetary fish nor fowl. They're neither terrestrial nor gaseous and range in size from about four to ten Earth masses. If we don't understand how these sub-Neptunes' chemical species are abiotically generated by the planet's geology, then when we detect them in an exoplanetary atmosphere, we could have a false positive, Kevin Heng, professor of astrophysics at the Ludwig Maximilian University of Munich, tells me in Iceland. This is a problem that's not likely to abate anytime soon. That's because, as yet, there's no reliable formula for detecting extrasolar signatures of life (or biosignatures). Some 40 of these bizarre, geochemically-active sub-Neptunes are currently being studied observationally. But without a firm understanding of the geochemical underpinnings of a rocky planet, we cannot possibly begin to understand whether some purported disequilibrium chemistry can be attributable to a biological process, Stephen Mojzsis, a geologist at the University of Bayreuth in Germany, tells me via email. Both Heng and Mojzsis are leaders in a 10-million-euro, six-year European Research Council-funded project dubbed 'Geoastronomy.' The aim is to unite the disciplines of astrophysics and the geosciences in an effort to comprehend both the chemistry and physics of rocky exoplanets. Fear Of False Positives In his recent Iceland presentation abstract, Heng challenges his colleagues by asking: If we cannot understand hot, geologically active exoplanets without life, what chances do we have of understanding a full-blown planetary biosphere from far away? Again, this clearly is an area of astrobiology that needs attention. There are potentially hundreds of such sub-Neptunes in the local galaxy, some of which orbit their parent stars in only a few days. And even though they have puffy hydrogen-rich atmospheric envelopes, these envelopes make up just 1% of their mass. Their cores, however, are thought to be rocky and molten, which probably means that they are geochemically active. High Pressure Their cores are basically molten rock with temperatures of a few thousand degrees and with pressures 10,000 times that of Earth's surface. At these pressures, there's probably no life, and matter behaves in an unfamiliar way, so that the distinction between gases and liquids are not so distinct and matter is in this strange, exotic mix, says Heng. Too Much Gas? At some point you add so much hydrogen to this core that its hydrogen doubles the size of the core which means that the real extent of the core is the same as the real extent of the atmosphere, Heng notes in his conference talk. Arguably, the most famous sub-Neptune is K2-18b, an exoplanet which recently made global headlines due to the claim that dimethyl sulfide had been detected in its atmosphere. But Heng doesn't buy that explanation. I find K2-18b utterly uninteresting because it's a red herring; we're going from physics to biology when there's so much geology we can learn, says Heng. The sample of exoplanets from which we can learn geology is vastly bigger than the sample of so-called habitable exoplanets, he says. Science can also be impatient. Most people want to make the leap from physics to biology, but let's take what nature is teaching us, says Heng. False positives come from geology because rocks use the same gases that metabolism uses, he says. A Habitability Skeptic Because we have yet to detect any real Earth analogs; we have a sample size of one for life, says Heng. All of the so-called habitable zone planets we have found are based on the assumption that they have the same atmosphere as Earth, and we do not know that they do, he says.
Business Times
02-07-2025
- Automotive
- Business Times
GrabCab, Singapore's newest taxi operator, hits the roads with over 40 cabs to be rolled out in July
[SINGAPORE] Singapore's sixth and newest taxi operator GrabCab has hit the roads, with over 40 cabs to be rolled out in July, and more cabs expected in the next three years. Its flag-down fare is S$4.60 for a standard four-seater vehicle, while distance rates are 26 Singapore cents for every 400m under 10km, and 26 cents for every 350m after 10km. A fee of 26 cents will be charged for every 45 seconds of waiting. Fares for taxis under ComfortDelGro, Trans-Cab, Strides Premier and Prime Taxi are comparable. GrabCab was launched on Jul 2 with a flag-off ceremony at Grab's headquarters in one-north. The taxi operator, a subsidiary of Grab's rental arm GrabRentals, announced its entry into the market on June 4, with 40 new fifth-generation electric hybrid Toyota Prius cars. Under the terms of its street-hail operator licence, GrabCab has three years to progressively expand its fleet to meet the minimum fleet size requirement of 800 cabs. The operator aims to achieve the target before the third year, said a Grab spokesperson. BT in your inbox Start and end each day with the latest news stories and analyses delivered straight to your inbox. Sign Up Sign Up Grab had said in June that it will add two more models to its fleet, including the electric hybrid Hyundai Kona from August and a fully electric vehicle 'some time' in 2025. The Hyundai Kona will be up for rental from Jul 3. Rental rates for a GrabCab vehicle start at S$106.20 a day, and with incentives, the rate falls to S$95.70 a day. This is comparable to the S$117 rental rate for a Toyota Prius under taxi giant ComfortDelGro, S$109.80 for one under Prime Taxi, and S$100 a day at Strides Premier. Fourteen Toyota Prius cars were involved in the flag-off, and some 30 drivers with the new taxi operator attended the event. Speaking at the flag-off ceremony, Grab's group managing director of operations Yee Wee Tang said: 'Ride-hailing apps work great for many commuters, but there are still groups like the older residents and overseas visitors who continue to need a street-hail service, and taxis fill the gap. 'At the same time, by bringing taxis and private-hire vehicles together on one platform, we're strengthening the overall network to provide more reliable and accessible rides for commuters across Singapore.' GrabCab also offers industry-first features such as a safe driving bonus, which rewards accident-free driving with up to S$3,000 over three years, and a relief-matching system in the driver app that lets main drivers connect with relief drivers. One of the fleet's new drivers, Kevin Heng, said he did not expect to join the taxi industry so soon. The 45-year-old was a delivery rider for four years before joining GrabCab, but was initially undecided between driving a taxi or a private-hire vehicle. Heng eventually chose a taxi after doing his homework by reading forums, due to benefits such as flexibility for street-hail pickups. His father, who was a ComfortDelGro taxi driver for 15 years, also encouraged him to consider the taxi industry. Heng signed with GrabCab for one year to 'try out' and for benefits such as leave and insurance coverage – drivers have accident coverage and up to two weeks of medical leave. Fees for the course to get the taxi driver's vocational licence are also fully funded by GrabCab. 'My friends all discouraged me and said driving a taxi is for old people,' Heng said. 'But I think this misconception must change.' THE STRAITS TIMES
