Today's Featured Links:
Space Cancer: https://www.unlv.edu/news/release/stu...
August’s Presentation: https://www.youtube.com/watch?v=nv7V4...
ALMA Shows Cold Object: https://public.nrao.edu/news/2017-alm...
Kepler452b Habitability: https://arxiv.org/pdf/1706.01224.pdf
Dust: https://weather.com/news/news/blowing...
ProtoDisk: http://www.eso.org/public/news/eso1611/
At the EU2015 conference this past June, the well known “skeptic” Michael Shermer participated in a panel discussion on the topic, "When Radical Ideas Challenge Conventional Science." Wal Thornhill and Dave Talbott also participated, along with Dr. Gary Schwartz of the University of Arizona. Subsequently, Dr. Shermer’s dismissive review of the conference appeared in Scientific American, October 2015. But now Dr. Shermer’s review itself is the subject of critical analysis, including comments from Dr. Donald Scott and mathematician Stephen Crothers. You can be certain that others will add to the discussion in coming weeks.
Left to right: Gary Schwartz, Dave Talbott, Michael Shermer, and Wal Thornhill. Moderated by Andy Bartlett.
"Changes in the X-rays are a direct probe of the collision zone and reflect changes in how these stars lose mass," said Michael Corcoran, an astrophysicist with the Universities Space Research Association headquartered in Columbia, Maryland. He and his colleagues compared periastron emission measured over the past 20 years by NASA's Rossi X-ray Timing Explorer, which ceased operation in 2012, and the X-ray Telescope aboard NASA's Swift satellite. In July 2014, as the stars rushed toward each other, Swift observed a series of flares culminating in the brightest X-ray emission yet seen from Eta Carinae. This implies a change in mass loss by one of the stars, but X-rays alone cannot determine which one.
Eta Carinae is a binary system containing the most luminous and massive star within 10,000 light-years. A long-term study led by astronomers at NASA's Goddard Space Flight Center in Greenbelt, Maryland, combined data from NASA satellites, ground-based observing campaigns and theoretical modeling to produce the most comprehensive picture of Eta Carinae to date. New findings include Hubble Space Telescope images that show decade-old shells of ionized gas racing away from the largest star at a million miles an hour, and new 3-D models that reveal never-before-seen features of the stars' interactions.
Located about 7,500 light-years away in the southern constellation of Carina, Eta Carinae comprises two massive stars whose eccentric orbits bring them unusually close every 5.5 years. Both produce powerful gaseous outflows called stellar winds, which enshroud the stars and stymy efforts to directly measure their properties. Astronomers have established that the brighter, cooler primary star has about 90 times the mass of the sun and outshines it by 5 million times. While the properties of its smaller, hotter companion are more contested, Goddard's Ted Gull and his colleagues think the star has about 30 solar masses and emits a million times the sun's light.
At closest approach, or periastron, the stars are 140 million miles (225 million kilometers) apart, or about the average distance between Mars and the sun. Astronomers observe dramatic changes in the system during the months before and after periastron. These include X-ray flares, followed by a sudden decline and eventual recovery of X-ray emission; the disappearance and re-emergence of structures near the stars detected at specific wavelengths of visible light; and even a play of light and shadow as the smaller star swings around the primary.
During the past 11 years, spanning three periastron passages, the Goddard group has developed a model based on routine observations of the stars using ground-based telescopes and multiple NASA satellites. According to this model, the interaction of the two stellar winds accounts for many of the periodic changes observed in the system. The winds from each star have markedly different properties: thick and slow for the primary, lean and fast for the hotter companion. The primary's wind blows at nearly 1 million mph and is especially dense, carrying away the equivalent mass of our sun every thousand years. By contrast, the companion's wind carries off about 100 times less material than the primary's, but it races outward as much as six times faster.
The images and video on this page include periastron observations from NASA's Rossi X-ray Timing Explorer, the X-Ray Telescope aboard NASA's Swift, the Hubble Space Telescope's STIS instrument, and computer simulations. See the captions for details.
This video is public domain and can be downloaded at: http://svs.gsfc.nasa.gov/goto?11725
The Slooh Community Observatory will broadcast a double feature about Comet Siding Spring's close pass by Mars on Sunday (Oct. 19). The first Slooh webcast will start at 2:15 p.m. EDT (1815 GMT), and the second will begin at 8:30 p.m. EDT (0030 Oct. 20 GMT).
"A Birkeland current usually refers to the electric currents in a planet's ionosphere that follows magnetic field lines (ie field-aligned currents), and sometimes used to described any field-aligned electric current in a space plasma.[3] They are caused by the movement of a plasma perpendicular to a magnetic field. Birkeland currents often show filamentary, or twisted "rope-like" magnetic structure. They are also known as field-aligned currents, magnetic ropes and magnetic cables). From plasma-universe(dot)com. All of this is well-established science.
The Lyrids meteor shower are usually active between April 16 and April 25 every year. It tends to peak around April 22 or April 23.
Considered to be the oldest known meteor shower, the Lyrids are named after constellation Lyra. The radiant point of the shower - the point in the sky where the meteors seem to emerge from - lies near the star Vega, one of the brightest stars in the sky during this time of the year.
The Lyrids are associated with comet Thatcher, which takes about 415 years to orbit around the Sun.
| Lyrids meteor shower for Phoenix | ||
|---|---|---|
| Time | Azimuth/ Direction | Altitude |
| Mon 9:00 PM | 51° | 0.9° |
| Mon 10:00 PM | 59° | 10.8° |
| Mon 11:00 PM | 65° | 21.8° |
| Midnight Mon-Tue | 71° | 33.5° |
| Tue 1:00 AM | 76° | 45.5° |
| Tue 2:00 AM | 82° | 57.8° |
| Tue 3:00 AM | 88° | 70.3° |
| Tue 4:00 AM | 99° | 82.8° |
| Tue 5:00 AM | 257° | 84.2° |
 |
| 10pm in Phoenix, Arizona |
Mars is bright now! It’s easy to see with the unaided eye from all parts of Earth – as bright as the sky’s brightest star. Mars is brighter than it’s been for six years, since December 2007.
Quite literally, this is Mars’ day in the sun. Take advantage, for Mars won’t be returning to opposition again until May 22, 2016.
By the way, Mars is not precisely closest to Earth on April 8, the day of opposition. Our two worlds will be closest together on April 14. On that night, Mars and the star Spica will appear near the moon as the moon undergoes a total eclipse!
“A reversal of the sun's magnetic field is, literally, a big event,” NASA’s Dr. Tony Phillips said in a statement issued on the space agency’s website.
“The sun's polar magnetic fields weaken, go to zero and then emerge again with the opposite polarity. This is a regular part of the solar cycle,” Stanford solar physicist Phil Scherrer explained.
The process has been slow and steady, with solar physicist Todd Hoeksama telling Metro: “It’s kind of like a tide coming in or going out. Each little wave brings a little more water in, and eventually you get to the full reversal.”
Scherrer explained earlier in December that “the sun's north pole has already changed sign, while the South Pole is racing to catch up.”
“The domain of the sun's magnetic influence (also known as the 'heliosphere') extends billions of kilometers beyond Pluto. Changes to the field's polarity ripple all the way out to the Voyager probes, on the doorstep of interstellar space,” Phillips explained.
Solar Cycle 24 has been viewed as quite unpredictable. First, it came late by about a year, with extremely low activity recorded throughout 2009. This prompted astronomers to shift a predicted 2012 peak to 2013. Scientists say the cycle is already among the weakest reported and if the trend continues, the Earth might see another Little Ice Age.