Tag: astronomy

More Earthlike exoplanets!

9:13 am

Astronomers using data from Kepler have discovered two stars, both with multiple orbiting Earth-sized planets. One has three planets all almost exactly the mass of Earth.

The first exoplanetary system is located in the star K2-239, characterized by these researchers as a red dwarf type M3V from observations made with the Gran Telescopio Canarias (GTC), at the Roque de los Muchachos Observatory (Garafía, La Palma). It is located in the constellation of the Sextant at 50 parsecs from the Sun (at about 160 light years). It has a compact system of at least three rocky planets of similar size to the Earth (1.1, 1.0 and 1.1 Earth radii) that orbit the star every 5.2, 7.8 and 10.1 days, respectively.

The other red dwarf star called K2-240 has two super-Earth-like planets about twice the size of our planet. Although the atmospheric temperature of red dwarf stars, around which these planets revolve, is 3,450 and 3,800 K respectively, almost half the temperature of our Sun, these researchers estimate that all planets discovered will have temperatures superficial tens of degrees higher than those of the planet Earth due to the strong radiation they receive in these close orbits to their stars.

Knowing more about the surface environments of these very Earthlike exoplanets, as hostile as they might be to life, would teach us a great deal about our own planet and its birth and evolution.

5 comments

More problems for James Webb Space Telescope?

9:45 am

The impending release of an independent NASA review of the state of the James Webb Space Telescope project suggests that the project is faced with additional issues.

NASA is in the process of evaluating the report from the Independent Review Board chaired by Tom Young to assess the status of the James Webb Space Telescope (JWST). Established in March, the Board was due to submit its report on May 31. NASA said today that the Board has completed its work and briefed NASA. The report will be released later this month after NASA determines the impact on cost and schedule.

Thomas Zurbuchen, NASA Associate Administrator for the Science Mission Directorate, created the Webb Independent Review Board (WIRB) on March 27, the same day he announced another delay in the telescope’s launch. WIRB held its first meeting the next week.

For many years, JWST appeared to be on track for launch in October 2018 after a 2011 restructuring that followed a series of earlier cost overruns and schedule delays. Congress capped the development cost (not operations) at $8 billion in law. Pursuant to the 2005 NASA Authorization Act, if a program exceeds 30 percent of its baseline estimated cost, NASA must notify Congress and no money may be spent on it after 18 months from the time of that notification unless Congress reauthorizes it.

The project will not die, Congress will simply extend it with lots more money. That is how big NASA projects really function, to take as long as possible so that they can continue their real goal of providing pork barrel jobs in congressional districts.

4 comments

No giant planet needed in Kuiper Belt to shape orbits of outer known planets

9:27 am

Using computer models astronomers have found that the tiny objects in the Kuiper Belt could be sufficient, instead of one giant undiscovered planet, to provide the gravity necessary to explain the orbits of the solar system’s outer planets.

They call theorized giant planet “Planet Nine,” which seems silly since Pluto really still fills that role. Nonetheless, this work also might explain the process that flung some surprisingly large objects so far out into the Kuiper Belt.

They ran supercomputer simulations of how bodies might interact in the outer Solar System far beyond Pluto, in the icy region known as the Kuiper belt. They found that a flock of Moon-sized worlds could do many of the same things as Planet Nine.

Over millions of years, the collective gravity of these smaller worlds would nudge the orbits of distant objects. The worlds would jostle one another like bumper cars and, occasionally, cause an object to move into a very distant orbit. Their simulations suggest that more-massive objects would be flung into the most distant orbits — as some observations have suggested.

We must also remind ourselves that this conclusion is based on a computer model, and is filled with uncertainty. We also do not yet have a full census of objects in the Kuiper Belt, which means this model required many assumptions.

0 comments

Globular clusters not as old as universe?

9:04 am

The uncertainty of science: A new computer model, based on binary star systems found in globular clusters, now estimates that those clusters are far younger than previously believed.

Comprised of hundreds of thousands of stars densely packed into a tight ball, globular clusters had been thought to be almost as old as the Universe itself – but thanks to newly developed research models it has been shown that they could be as young as 9 billion years old rather than 13 billion. The discovery brings into question current theories on how galaxies, including the Milky Way, were formed – with between 150-180 clusters thought to exist in the Milky Way alone – as globular clusters had previously been thought to be almost as old as the Universe itself.

Designed to reconsider the evolution of stars, the new Binary Population and Spectral Synthesis (BPASS) models take the details of binary star evolution within the globular cluster into account and are used to explore the colours of light from old binary star populations – as well as the traces of chemical elements seen in their spectra. The evolutionary process sees two stars interacting in a binary system, where one star expands into a giant whilst the gravitational force of the smaller star strips away the atmosphere, comprising hydrogen and helium amongst other elements, of the giant. These stars are thought to be formed as the same time as the globular cluster itself.

Through using the BPASS models and calculating the age of the binary star systems the researchers were able to demonstrate that the globular cluster of which they are part was not as ancient as other models had suggested.

All this study really does is demonstrate again that we really don’t know enough to make a very accurate estimate of the ages of globular clusters. They are very old, but determining precisely how old will require a lot more knowledge.

1 comment

Boulder-sized asteroid discovered just before it hit Earth

8:59 am

The Catalina Sky Survey, designed to find asteroid with the potential of hitting the Earth, discovered a boulder-sized such asteroid this past weekend just hours before it burned up in the atmosphere.

Although there was not enough tracking data to make precise predictions ahead of time, a swath of possible locations was calculated stretching from Southern Africa, across the Indian Ocean, and onto New Guinea. Reports of a bright fireball above Botswana, Africa, early Saturday evening match up with the predicted trajectory for the asteroid. The asteroid entered Earth’s atmosphere at the high speed of 10 miles per second (38,000 mph, or 17 kilometers per second) at about 16:44 UTC (9:44 a.m. PDT, 12:44 p.m. EDT,6:44 p.m. local Botswana time) and disintegrated several miles above the surface, creating a bright fireball that lit up the evening sky. The event was witnessed by a number of observers and was caught on webcam video.

When it was first detected, the asteroid was nearly as far away as the Moon’s orbit, although that was not initially known. The asteroid appeared as a streak in the series of time-exposure images taken by the Catalina telescope . As is the case for all asteroid-hunting projects, the data were quickly sent to the Minor Planet Center in Cambridge, Massachusetts, which calculated a preliminary trajectory indicating the possibility of an Earth impact. The data were in turn sent to the Center for Near-Earth Object Studies (CNEOS) at NASA’s Jet Propulsion Laboratory in Pasadena, California, where the automated Scout system also found a high probability that the asteroid was on an impact trajectory. Automated alerts were sent out to the community of asteroid observers to obtain further observations, and to the Planetary Defense Coordination Office at NASA Headquarters in Washington. However, since the asteroid was determined to be so small and therefore harmless, no further impact alerts were issued by NASA.

The video at the link makes it appear that the asteroid has hit the ground, but that is not what happened.

0 comments

Radio telescope in Greenland sees first “light”

10:03 am

Astronomers have successfully initiated operations of a new radio telescope dish, the first ever located in Greenland.

The Greenland Telescope is a 12-meter radio antenna that was originally built as a prototype for the Atacama Large Millimeter/submillimeter Array (ALMA) North America. Once ALMA was operational in Chile, the telescope was repurposed to Greenland to take advantage of the near-ideal conditions of the Arctic to study the Universe at specific radio frequencies, collaborating with the National Radio Astronomy Observatory (NRAO) and MIT Haystack Observatory.

ASIAA led the effort to refurbish and rebuild the antenna to prepare it for the cold climate of Greenland’s ice sheet. In 2016, the telescope was shipped to the Thule Air Base in Greenland, 1,200 km inside the Arctic Circle, where it was reassembled at this coastal site. ASIAA also built receivers for the antenna. “It is extremely challenging to quickly and successfully set up a new telescope in such a cold environment, where temperatures fall below -30 degrees Celsius,” said Ming-Tang Chen from ASIAA and the Greenland Telescope project manager. “This is now one of the closest radio telescopes to the North Pole.”

They have also linked this radio telescope to others across the globe, helping to increase the resolution of any data these radio telescopes gather as a unit.

1 comment

Canada exits WFIRST project

9:32 am

Like rats fleeing a sinking ship: The Canadian government has decided not to fund that country’s contribution to NASA’s WFIRST space telescope project, presently expected to cost $3.2 billion total (already over-budget in the design phase) and set to launch sometime in the 2020s (don’t bet on it).

The Canadian instrument would have been focused on studying dark energy, the mysterious force that is theorized to cause the universe’s expansion rate to accelerate over vast distances.

I can understand the skepticism of the Canadian government. Why commit anything to a project that is already over-budget and has unreliable support in the U.S. (Trump tried to ax it, Congress restored it, for now)? The project is also so far in the future it makes more sense to spend this money on astronomy projects that could be built and used now.

0 comments

Astronomers identify 25 stars that have or will come within 3 light years of Sun

9:21 am

Using the second data release from Gaia, astronomers have identified 25 stars that have or will come within 3 light years of Sun sometime within fifteen million years.

But the authors are confident that the 25 stars represent only a sliver of the actual encounters that have occurred over this time period. “They’re still just scratching the surface,” Mamajek agrees. That’s because the Gaia satellite eliminates low-mass stars (which are simply too faint to see at the moment) and high-mass stars (which are often so bright they saturate the satellite’s detectors) — thus limiting the data to stars that range between 0.5 and 1.3 times the mass of the Sun.

As such, the team suspects that they have only spotted 15% of all the encounters that likely pummel our solar system. “It’s a good first step, but one should not look at this as the final word,” Mamajek adds.

In reading their paper (available here), they identify three stars come come within a light year, therefore disturbing the theorized Oort Cloud of comets thought to exist at this distance from the Sun. One, Gliese 710, will do so in 1.3 million years..

3 comments

New tests prove EM drive doesn’t work

11:26 am

Two different alternative concepts that proposed methods for creating thrust in space but defied known physics have both been found wanting in new stringent experiments.

The EM drive especially came off badly. Apparently the tiny residual force that remains after building the experiment rigorously and with care is caused not by the EM drive but by the Earth’s magnetic field.

Readers of Behind the Black know that I am a strong skeptic when it comes to flashy new discoveries, whether they are made by famous and well known cosmologists or some guys in their garage. To me, what matters is the data, and its reliability and robustness. The EM drive never passed the smell test. Good science experimentation has now proven this.

12 comments

Two giant U.S. telescope projects team up

9:21 am

The two consortiums building the Thirty Meter Telescope (TMT) and the Giant Magellan Telescope (GMT) have teamed up in order to coordinate their research as well as encourage increased government funding for both.

The partnership, approved by the GMT board this month and by the TMT board last month, commits the two projects to developing a joint plan that would allow astronomers from any institution to use the telescopes; under previous plans observing time was available only to researchers from nations or institutions that had provided funding. The projects are discussing awarding at least 25% of each telescope’s time to nonpartners through a competitive process to be administered by the National Center for Optical-Infrared Astronomy—an umbrella organization that will replace the National Optical Astronomy Observatory (NOAO), based in Tucson, Arizona, sometime in fiscal year 2019. Telescope backers hope the public access plan will help persuade the federal government to pay for at least 25% of the total cost of the two facilities, which could total $1 billion. (Cost estimates for the GMT and the TMT are $1 billion and $1.4 billion, respectively, but astronomers expect both numbers to grow.) “There are many science projects that are $1 billion class projects,” says David Silva, NOAO’s director. “The investment that we would want is of a similar size.”

…In making their case, the teams will argue the benefits of having telescopes in both the northern and southern hemispheres. “When you are covering the whole sky, you have greater scientific reach,” says Wendy Freedman, an astronomer at The University of Chicago in Illinois who was the founding leader of the GMT. The teams will also argue that the telescopes have complementary strengths. The design of the GMT, for instance, makes it ideal for a high-resolution spectrograph designed to probe the atmospheres of exoplanets. The TMT, which has more light-gathering power, could host a multiobject spectrograph to quickly gather demographic statistics on the universe’s first galaxies. [emphasis mine]

The highlighted sentences explain everything. First, government funding for both projects has been weak, partly because the National Science Foundation (the funding agency) has not been able to make up it mind which of these two U.S. projects to back. By teaming up as one project building two telescopes, the builders hope they will grease the wheels of the federal funding machine.

Second, by selling these two telescopes as covering both the north and south hemispheres, they indicate that the TMT is now almost certainly going to abandon its Hawaii location and move to the Canary Islands. GMT will be built at the Las Campanas Observatory in Chile, located at 29 degrees south latitude. By placing TMT in the northern hemisphere at 29 degrees north latitude in the Canary Islands, rather than Mauna Kea’s 19 degrees north latitude, they better compliment GMT in the southern hemisphere.

In other words, this partnership strengthens the case for TMT to abandon Hawaii. Not only will construction begin sooner (as the Hawaiian government has shown no interest in approving the project), the higher latitude as part of this partnership better justifies funding.

And the odds of getting that funding have apparently increased, as the chair of the House appropriations panel that funds the National Science Foundation has just shown himself to be very willing to give telescope projects a lot of money, more in fact than they even request.

2 comments

Astronomers detect oxygen only 250 million years after Big Bang

12:58 pm

The uncertainty of science: Astronomers have detected oxygen in a galaxy formed only 250 million years after Big Bang, suggesting that star formation started much sooner than expected.

As we look deeper and deeper, the onset of stellar formation keeps getting pushed back closer and closer to the Big Bang, and always sooner than the theories and computer models predicted.

0 comments

Europa water plume detected in old Galileo data

8:22 am

Using old Galileo data and new techniques of analysis scientists have uncovered a water plume on Europa that the spacecraft flew through in 1997.

Over the course of 5 minutes, spikes the spacecraft recorded with its magnetic and plasma sensors reflected the alterations that a veil of ejected water, from one or many vents, could cause in a region matching the telescope observations, they report today in Nature Astronomy. This indicates that a region of the moon potentially 1000 kilometers long could host such activity, though it is impossible to say whether this is a single plume or many, like the complex system of fractures and vents seen on Enceladus. Indeed, on its own, this evidence was too weak to tie to erupting water in a 2001 study describing it, the authors add, but it fits well with the Hubble and modeled evidence.

As indicated by the quote above, the result has a lot of uncertainty.

0 comments
1 … 87 88 89 90 91 … 188