NASA Earth Observatory: Arctic sea ice appeared to reach its annual minimum extent on September 10, 2016, NASA and the National Snow and Ice Data Center (NSIDC) reported today. An analysis of satellite data showed that sea ice around the North Pole shrank to 4.14 million square kilometers (1.60 million square miles). The 2016 sea […]
NEW YORK (CBSNewYork/AP) — A museum in the city is offering visitors a chance to sit on a golden throne, but only in private. As part of his “America” exhibit at the Solomon R. Guggenheim Museum, Italian artist Maurizio Cattelan replaced the toilet in the museum’s fourth-floor restroom with a fully functional replica cast in 18-karat gold.…
TUCKAHOE, N.Y. (CBSNewYork) — A town hall meeting in Tuckahoe turned explosive on Thursday night, as residents say they are terrified by the city’s plan to build a Marriott Hotel on a site they claim is toxic. As CBS2’s Jessica Layton reported, sparks flew, fingers were pointed, and blood was boiling as the Tuckahoe planning…
July 21, 2016 – NASA’s Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission is a first-of-its-kind project that aims to answer key questions about the consequences of climate change on the health of our oceans and their relationship with airborne particles and clouds. PACE will use a wide spectrum of wavelengths from an “ocean color” instrument to provide scientists with this information.
“PACE represents a major effort to truly combine ocean research with atmospheric research,” Project Scientist Jeremy Werdell said. “We are going to go beyond just seeing that Earth’s climate is changing to better understanding why the change is occurring.”
PACE was approved to move forward out of its preliminary stage of planning on June 16 at the Key Decision Point A (KDP-A) event. A significant milestone for this next stage is that the official mission budget becomes available for use on July 1, Project Manager Andre Dress said.
The primary instrument for this mission is named the Ocean Color Instrument (OCI), which will collect hyperspectral measurements from the ultraviolet to the shortwave infrared—a range that is broader than its predecessor satellite instruments, SeaWiFS, MODIS, and VIIRS—to examine and monitor how phytoplankton communities in the ocean are changing in space and time. The OCI will provide precise measurements of the ocean surface to allow researchers to see the concentrations of different phytoplankton communities all over the globe. The spectral range and resolution of the OCI design will substantially advance the ability to distinguish between different species of phytoplankton compared to predecessor satellite instruments.
Phytoplankton play an essential role in ocean ecosystems. They are the base of the marine food chain and, like land plants, produce much of the oxygen we breathe and play a role in reducing atmospheric carbon dioxide levels. With growing concern about the impact of rising global temperatures on our oceans, PACE data will be used to unveil new information about changing patterns in phytoplankton composition and the emergence of potentially harmful algal blooms. Satellites that currently exist are adept at detecting algal blooms, but cannot unequivocally determine their composition – for example, if they are harmful to fish or can contaminate drinking water. The spectral range of OCI will help scientists figure out more about where blooms occur and how they are changing.
The possible addition of a polarimeter, an instrument that could provide multi-angle polarized radiometric measurements to advance studies of aerosol particles and clouds, is currently under consideration by the PACE team. A polarimeter would allow improved measurement of atmospheric particle compositions that will ultimately improve observations of ocean color. Normally, roughly ninety percent of what an ocean color satellite instrument measures when over the oceans is the atmosphere, which has to be subtracted out to reveal the ocean signal.
Ongoing field campaigns and the collection of data at sea provide critical information that helps scientists and engineers plan and design this new mission. For example, the North Atlantic Aerosols and Marine Ecosystems Study (NAAMES) campaign, which had its most recent deployment during May 2016, collected a wealth of information from both a ship and an airplane to validate satellite measurements and give a three-dimensional perspective that includes what’s happening beneath the surface. “NAAMES is helping us answer fundamental questions we have about processes in the ocean,” said PACE Communications Coordinator and scientist Stephanie Uz. “The measurements they and other field campaigns collect at sea contribute to PACE being a giant leap forward in ocean and atmosphere research.”
All preliminary planning for PACE is currently being done at NASA’s Goddard Space Flight Center. The unique information that this mission will provide, in combination with climate models, will allow for scientists to monitor the health of our oceans and their response to climate change like never before.
“We are putting all this carbon dioxide into the atmosphere and causing oceans to be more acidic at the same time that the oceans are warming and coming under stress from a range of human activities,” Uz said. “All of this is affecting the ocean in ways we don’t fully understand…PACE will help us comprehend what we have now and how it is changing.”
July 20, 2016 – On May 2, scientists from MIT, the University of Liège, and elsewhere announced they had discovered a planetary system, a mere 40 light years from Earth, that hosts three potentially habitable, Earth-sized worlds. Judging from the size and temperature of the planets, the researchers determined that regions of each planet may be suitable for life.
Now, in a paper published today in Nature, that same group reports that the two innermost planets in the system are primarily rocky, unlike gas giants such as Jupiter. The findings further strengthen the case that these planets may indeed be habitable. The researchers also determined that the atmospheres of both planets are likely not large and diffuse, like that of the Jupiter, but instead compact, similar to the atmospheres of Earth, Venus, and Mars.
The scientists, led by first author Julien de Wit, a postdoc in MIT’s Department of Earth, Atmospheric and Planetary Sciences, came to their conclusion after making a preliminary screening of the planets’ atmospheres, just days after announcing the discovery of the planetary system.
On May 4, the team commandeered NASA’s Hubble Space Telescope and pointed it at the system’s star, TRAPPIST-1, to catch a rare event: a double transit, the moment when two planets almost simultaneously pass in front of their star. The researchers realized the planets would transit just two weeks before the event, thanks to refined estimates of the planets’ orbital configuration, made by NASA’s Spitzer Space Telescope, which had already started to observe the TRAPPIST-1 system.
“We thought, maybe we could see if people at Hubble would give us time to do this observation, so we wrote the proposal in less than 24 hours, sent it out, and it was reviewed immediately,” de Wit recalls. “Now for the first time we have spectroscopic observations of a double transit, which allows us to get insight on the atmosphere of both planets at the same time.”
Using Hubble, the team recorded a combined transmission spectrum of TRAPPIST-1b and c, meaning that as first one planet then the other crossed in front of the star, they were able to measure the changes in wavelength as the amount of starlight dipped with each transit.
“The data turned out to be pristine, absolutely perfect, and the observations were the best that we could have expected,” de Wit says. “The force was certainly with us.”
A rocky sign
The dips in starlight were observed over a narrow range of wavelengths that turned out not to vary much over that range. If the dips had varied significantly, de Wit says, such a signal would have demonstrated the planets have light, large, and puffy atmospheres, similar to that of the gas giant Jupiter.
But that’s not the case. Instead, the data suggest that both transiting planets have more compact atmospheres, similar to those of rocky planets such as Earth, Venus, and Mars.
“Now we can say that these planets are rocky. Now the question is, what kind of atmosphere do they have?” de Wit says. “The plausible scenarios include something like Venus, where the atmosphere is dominated by carbon dioxide, or an Earth-like atmosphere with heavy clouds, or even something like Mars with a depleted atmosphere. The next step is to try to disentangle all these possible scenarios that exist for these terrestrial planets.”
More eyes on the sky
The scientists are now working to establish more telescopes on the ground to probe this planetary system further, as well as to discover other similar systems. The planetary system’s star, TRAPPIST-1, is known as an ultracool dwarf star, a type of star that is typically much cooler than the sun, emitting radiation in the infrared rather than the visible spectrum.
De Wit’s colleagues from the University of Liège came up with the idea to look for planets around such stars, as they are much fainter than typical stars and their starlight would not overpower the signal from planets themselves.
The researchers discovered the TRAPPIST-1 planetary system using TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope), a new kind of ground telescope designed to survey the sky in infrared. TRAPPIST was built as a 60-centimeter prototype to monitor the 70 brightest dwarf stars in the southern sky. Now, the researchers have formed a consortium, called SPECULOOS (Search for habitable Planets Eclipsing ULtra-cOOl Stars), and are building four larger versions of the telescope in Chile, to focus on the brightest ultracool dwarf stars in the skies over the southern hemisphere. The researchers are also trying to raise money to build telescopes in the northern sky.
“Each telescope is about $400,000—about the price of an apartment in Cambridge,” de Wit says.
If the scientists can train more TRAPPIST-like telescopes on the skies, de Wit says, the telescopes may serve as relatively affordable “prescreening tools.” That is, scientists may use them to identify candidate planets that just might be habitable, then follow up with more detailed observations using powerful telescopes such as Hubble and NASA’s James Webb Telescope, which is scheduled to launch in October 2018.
“With more observations using Hubble, and further down the road with James Webb, we can know not only what kind of atmosphere planets like TRAPPIST-1 have, but also what is within these atmospheres,” de Wit says. “And that’s very exciting.”
July 20, 2016 – SpaceX finally made good on its delivery of a space station docking port Wednesday morning.
A Dragon capsule arrived at the International Space Station, bearing more than 2 tons of supplies. The shipment includes a docking port needed for future rocket ships. SpaceX is working on a crew-worthy Dragon, while Boeing is developing a capsule for astronauts named Starliner.
SpaceX launched its latest Dragon from Cape Canaveral on Monday. A year earlier, the first of these new docking rings was destroyed in a SpaceX launch accident. NASA and Boeing—which makes the ports—is working on a replacement that should fly in another 1 ½ years.
The two U.S. space station residents used a robot arm for Wednesday’s 250-mile-high operation above America’s Great Lakes.
“We’ve captured us a Dragon,” reported astronaut Jeffrey Williams. “We look forward to the work that it brings.”
Mission Control replied, “This event is an important step on the journey of the International Space Station mission. Now let’s get this vehicle berthed so we can get to work.”
The newly arrived science experiments include a DNA decoder, or sequencer, that will get a workout by the first virus-hunter in space, NASA astronaut Kate Rubins.
This is the second high-flying delivery this week. A Russian supply ship pulled in Monday night.
Credit: Wageningen University |
July 19, 2016 – By using specific statistical methods, it has become possible to improve the risk assessment of nanoparticles. This was the conclusion of the PhD thesis that Rianne Jacobs defended on 7 July 2016 at Wageningen University. Jacobs showed that these techniques can be used in risk assessment to separate two important sources of error, which makes the results of the assessment more reliable.
Nanotechnology is a relatively new, but fast growing field. As with all novel materials, nanoparticles have no history of safe use. This makes it difficult to assess the risks. To create broad societal support for nanotechnology, it is essential to understand the risks. Important questions in this respect are the following: with limited experience, how can the risks be estimated as accurately as possible, and how can we quickly acquire more understanding of these risks? With her research, Jacobs wants to help answer questions like these.
Lack of knowledge and small sample sizes
There are two important reasons why it is difficult to assess the risk of nanoparticles. The first reason is the lack of knowledge: how do the particles become dispersed in the environment, how do people and other organisms come into contact with the particles and how harmful are they for these organisms? This lack of knowledge leads to uncertainty in the risk assessment. The second reason is that risk assessors often have to work with small sample sizes. This results in a large margin of error in the risk assessment. In her study, Jacobs has shown how statistical methods can help risk assessors deal with this uncertainty and these small sample sizes.
Uncertainty and variability
When estimating risk, researchers focus on measurements, but such measurements are never conclusive. Statistical techniques can help describe the variation in the measurements. An important consideration is that there are two separate effects: uncertainty and variability. Uncertainty results from a lack of knowledge, for example because researchers have not made enough measurements or they have not made them with sufficient accuracy. This can obviously be improved. Variability is the variation that is inherent to all natural processes and living organisms. For example, humans react differently to many substances than yeast cells do. This variation is a fact of nature; you cannot do anything to ‘improve’ it.
Integrated Probabilistic Risk Assessment
Jacobs successfully used the method known as Integrated Probabilistic Risk Assessment (IPRA) to separate these two types of variation. This method was developed to assess the health effects of chemicals on people, but Jacobs has adapted it to nanoparticles. With this method, risk assessors not only achieve a better result than with standard worst-case estimates, the method also identifies which sources of uncertainty contribute the most to the total uncertainty in the risk assessment. By focussing on these sources, the risk assessment can be improved substantially.
Examples from practice
In her investigation, Jacobs studied various applications of nanoparticles, such as nano silica in food products, titanium dioxide in cosmetics and medicines and antibacterial silver particles. With her approach, Jacobs was able to identify the most important sources of uncertainty in these applications. Based on this identification, research can focus on the most crucial areas, which leads to substantial progress in reducing the uncertainty that currently hampers the risk assessment of nanoparticles.