Is Earth slowly heading for a new ice age? Looking at the decreasing
number of sunspots, it may seem that we are entering a nearly spotless
solar cycle which could result in lower temperatures for decades. “The
solar cycle is starting to decline. Now we have less active regions
visible on the sun’s disk,” Yaireska M. Collado-Vega, a space weather
forecaster at NASA’s Goddard Space Flight Center, told Phys.org.
But does it really mean a colder climate for our planet in the near
future? In 1645, the so-called Maunder Minimum period started, when
there were almost no sunspots. It lasted for 70 years and coincided with
the well-known “Little Ice Age”, when Europe and North America
experienced lower-than-average temperatures. However, the theory that
decreased solar activity caused the climate change is still
controversial as no convincing evidence has been shown to prove this
correlation.
Helen Popova, a Lomonosov Moscow
State University researcher predicts that if the existing theories about
the impact of solar activity on the climate are true, then this minimum
will lead to a significant cooling, similar to the one during the
Maunder Minimum period. She recently developed a unique
physical-mathematical model of the evolution of the magnetic activity of
the sun and used it to gain the patterns of occurrence of global minima
of solar activity and gave them a physical interpretation.
“Given that our future minimum will last for at least three solar
cycles, which is about 30 years, it is possible that the lowering of the
temperature will not be as deep as during the Maunder Minimum,” Popova
said earlier in July. “But we will have to examine it in detail. We keep
in touch with climatologists from different countries. We plan to work
in this direction.”
The solar cycle is the periodic change in the Sun’s activity and
appearance like changes in the number of sunspots. It has an average
duration of about 11 years. The current solar cycle began on in January
2008, with minimal activity until early 2010. The sun is now on track to
have the lowest recorded sunspot activity since accurate records began
in 1750. The long-term decline in solar activity set in after the last
grand solar maximum peaked in 1956.
But according to Collado-Vega, the current minimum in the number of
sunspots doesn’t mean that the sun won’t show us its violent nature in
the coming years.
“There is a development for coronal holes, due to the reconfiguration
of the sun’s magnetic field, that bear the well-known high-speed
streams. These high-speed streams have the ability to cause strong
geomagnetic storms at Earth, and changes to the radiation environment in
the inner magnetosphere,” Collado-Vega noted.
Coronal holes are regions with lower density and temperatures in the
sun’s outer atmosphere, known as the corona. The sun contains magnetic
fields that arch away from areas in the corona that are very thin due to
the lower levels of energy and gas, which cause coronal holes to appear
when they do not fall back. Thus, solar particles or solar wind escape
and create a lower density and lower temperature in that area.
The existing fleet of spacecraft studying the sun includes the Solar
Dynamics Observatory (SDO), the Solar and Heliospheric Observatory
(SOHO) and the Solar Terrestrial Relations Observatory (STEREO), which
provide continuous solar observations that are currently enhancing our
knowledge about sun’s corona. And if that’s not enough, a new NASA probe
named Solar Probe Plus is being developed to revolutionize our
understanding of solar phenomena. Significantly, the mission, with a
planned launch in mid-2018, will fly closer to the sun than any previous
spacecraft. Its primary science goals are to trace the flow of energy
and understand the heating of the solar corona and to explore the
physical mechanisms that accelerate the solar wind and energetic
particles. This would definitely improve future solar activity forecasts
and help us more accurately predict the impact that the features on the
sun have on our planet.
Phys.org
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