Tag: sun

Hadrian built his country estate with the buildings aligned with the sun

9:18 am

The Roman emperor Hadrian built his country estate with the buildings aligned with the sun.

For centuries, scholars have thought that the more than 30 buildings at Hadrian’s palatial country estate were oriented more or less randomly. But De Franceschini says that during the summer solstice, blades of light pierce two of the villa’s buildings.

In one, the Roccabruna, light from the summer solstice enters through a wedge-shaped slot above the door and illuminates a niche on the opposite side of the interior (see image). And in a temple of the Accademia building, De Franceschini has found that sunlight passes through a series of doors during both the winter and summer solstices.

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Solar scientists predict a major decline in sunspot activity

1:37 pm

At a press conference today at the 2011 meeting of the Solar Physics Division (SPD) of the American Astronomical Society (AAS) in Las Cruces, New Mexico, solar scientists predicted that not only will the next solar maximum in 2013 be the weakest in centuries, it is very likely that it will be followed by another long Maunder Minimum, a period of decades without sunspots. “The sun may be going into hiatus,” says Dr. Frank Hill, associate director of the NSO’s Solar Synoptic Network. You can read the press releases for this announcement here and here.

decline in magnetic field over the last few cycles

These conclusions are based on three lines of evidence:

  • There has been a long term weakening in the magnetic strength that produces sunspots themselves. The declining trend suggests that by 2022 it will no longer be strong enough to produce sunspots. The graph above shows this decline.
    » Read more
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After a burst the Sun quiets down again

3:57 pm

Time again for the monthly updated graph of the Sun’s solar cycle sunspot activity. Posted today by NOAA’s Space Weather Prediction Center, you can see the May results in the graph below.

After a three month steady rise in sunspot activity in January, February, and March, the numbers plummeted during April and May. Though the Sun remains active, with only one blank day since January 16, the pattern of activity as it ramps up to solar maximum continues to suggest that we are looking for the weakest solar maximum in two hundred years, as now predicted by solar scientists at the Marshall Space Flight Center.

Whether this weak maximum foreshadows another Maunder-like minimum, with no sunspots occurring for decades, remains unknown. Only time will tell. However, if such a thing should happen, it will be a marvelous opportunity for scientists to finally pin down precisely the actual influence of the Sun on the Earth’s climate. Up until now they can only guess at how much the Sun varies in brightness. Another Maunder Minimum will tell them.

May Sunspot activity

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The Sun in April – Steady as she goes!

10:04 am

The monthly updated graph for April of the Sun’s solar cycle sunspot activity was posted yesterday by NOAA’s Space Weather Prediction Center. You can see it below.

Though the Sun remained active, you can see that the steep increase in sunspot activity that occurred in March has ceased. At the moment it looks as if the Sun’s sunspot activity is following the most recent scientific prediction, more or less exactly, though the small dip in April puts the numbers slightly below that prediction.

All in all, we still appear to be headed to the weakest solar maximum in two hundred years.

April Sunspot activity

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Hot time on the ol’ Sun tonight!

10:09 pm

After literally years of inactivity, well below all initial predictions, the Sun truly came to life this past month. Below is the March monthly update of the Sun’s sunspot cycle, published by NOAA’s Space Weather Prediction Center. The red curve is the prediction, while the dotted black line shows the actual activity.

As you can see, the Sun’s sunspot activity shot up precipitously. Though I don’t have the data from past years, the March jump appears to me to probably be one of the fastest monthly rises ever recorded.

Does this mean the newest prediction from the solar scientists at the Marshall Space Flight Center calling for a weak solar maximum in 2013 is wrong? Probably not, though of course in this young field who knows? I would say, however, that the overall trend of the data still suggests the next maximum will be very weak.

Stay tuned! The next few months should finally give us a sense of where the next maximum is heading.

March Sunspot graph

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More press release journalism,
this time about sunspots

10:01 am

Did you hear the news? Scientists have solved the mystery of the missing sunspots!

You didn’t? Well, here’s some headlines and stories that surely prove it:

The trouble is that every one of these headlines is 100 percent wrong. The research, based on computer models, only found that when the plasma flow from the equator to the poles beneath the Sun’s surface slows down, the number of sunspots declines.
» Read more

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The Massive February 15, 2011 X Flare on the Sun

8:02 pm

An evening pause: On February 15, 2011, the Sun emitted its strongest flare in four years. Though the Sun continues to act relatively wimpy as it ramps up towards solar maximum, this flare was spectacular, mostly because we now have some amazing instruments in space to image and study it. This video does an excellent job explaining what was happening, as it happened. Watch, and enjoy.

And note, as powerful as this flare was, and despite the fact that it was pointed right at the Earth, it represented a relatively minor threat to our technological society, despite what some doomsayers might be claiming. A very active Sun can cause us problems, especially with power systems and electrical grids, but based on past experience during previous solar maximums, most power companies have taken careful steps to protect themselves from this risk. And with the Sun as weakly active as it is, the risks are further reduced. The doomsayers are simply shilling for more government research dollars.

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The Sun’s continuing wimpiness

12:30 pm

Get those winter coats out of storage! Yesterday NOAA’s Space Weather Prediction Center published its monthly update of the Sun’s sunspot cycle. I’ve posted the newest graph below, showing the continuing slow rise in sunspots (blue/black lines) in comparison with the consensis prediction made by the solar science community in May 2009 (red line).

Though the sunspot count made a slight recovery in January, it was not enough to make up for the plunge in December. Essentially, the Sun continues to act like a sleepy kitten that really doesn’t want to wake up. This suggests that even the newest and wimpiest prediction for the next solar maximum, from solar scientists at the Marshall Space Flight Center, is still overstating the Sun’s upcoming sunspot activity.

In the past a wimpy Sun has been linked to cold weather, for reasons that scientists as yet don’t quiet understand. And this next solar maximum continues to look like the wimpiest in more than 200 years (see the graph on this page)!

January sunspot graph

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The solar maximum keep shrinking

2:53 am

Solar scientists at the Marshall Space Flight Center have once again revised downward their prediction for the intensity of the next solar maximum. Key quote:

Current prediction for the next sunspot cycle maximum gives a smoothed sunspot number maximum of about 59 in June/July of 2013. We are currently two years into Cycle 24 and the predicted size continues to fall.

If this prediction holds, the upcoming solar maximum could be the lowest since the cycle came back to life in around 1715 following the Maunder Minimum.

the solar cycle

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The future Nemesis from space

3:01 pm

From the American Astronomical Society meeting this week:

A team of astronomers, using the data from the Sloan Digital Sky Survey, calculated the galactic orbits of nearly 40,000 low mass stars. These stars are generally M dwarfs, cool, not very bright, and thus generally somewhat close to the Sun since if they are too far away we would not see them. You can read the abstract here, and download their full poster here [pdf].

For the astronomers, the data told them a great deal about the orbital properties of these stars. Though a majority are in circular orbits between 20 to 30 thousand light years from the galactic center, a small minority are in extremely eccentric orbits that travel far out into the galactic halo, as much 260,000 light years. A few others dive inward, getting within 6000 light years of the galactic center.

What made this poster stand out to me, however, was this quote from the abstract:

In addition, we have identified a number of stars that will pass very close to the Sun within the next [billion years]. These stars form the “Nemesis” family of orbits. Potential encounters with these stars could have a significant impact on orbits of Oort Cloud and Kuiper Belt members as well as the planets. We comment on the probability of a catastrophic encounter within the next [billion years].

All told, they found that 18 low-mass cool M dwarf stars that will eventually pass close to the Sun. One star, SDSS J112612.07+152517.6, an M3 star that is about 2,300 light years away, is in an orbit that has it moving right towards us at about 90,000 miles per hour. Its mass is less than half that of the Sun, about 0.4 solar masses. This figure from the poster roughly illustrates the star’s position relative to our solar system over the next billion years:

Nemesis star

The star itself is shown in the inset. The red curve shows its calculated distance from the Sun over time, with the black area above and below showing the uncertainties of the calculation. As you can see, every hundred million years or so the distance between this star and the Sun shrinks, with the very very very rare possibility that the distance will sometimes shrink to zero!

With 18 stars each doing this every few 100 million years or so, the average time between close approaches is about 5 million years. These results suggest that another star passes close enough to our solar system frequently enough to not only disturb the comets in the Oort cloud, but also possibly affect the orbits of the planets in the outer solar system and Kuiper belt. One wonders, for example, if such an event had some influence on Pluto’s strange orbit.

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