Since CMEs carry a lot of energy and mass away from the Sun and happen
so often we must understand them if we want to know how the Sun works.
It's like the Sun keeps coughing and we want to know what's making it
ill!

LASCO has helped us to understand CMEs better.

If we want to learn what effect CMEs have on the Sun and the Earth we
need to know how often they occur.
We now know that they are produced more often than we previously
thought.  Before SOHO
was launched it seemed that during the quiet part of the solar cycle
one could expect about 1 CME every 10 days.  LASCO has now shown us
that over 10 days we would really expect about 8 CMES during solar
minimum.  We have also learned that some CMEs are connected and travel
in a family group!  Large areas of the Sun can be disturbed by just one
CME.

**CME image feb 23 97 -- c2dis0**.gif**

As we approach Solar maximum (around 2001) we expect many more
CMEs per day.  How many we're not sure.  We'll have to wait and see!


CMEs are also bigger than we expected.  The first CME seen by LASCO
(15th January 1996) taught us that the masses of CME might be
seven times more massive than we thought.  If we want to make a good model
of how the Sun works we need to know how much mass CMEs carry away from
the Sun.  

**Image: January 15th CME -- jan15cme.gif** 
=====================================================================
Caption:  

C3 images of the first CME seen by LASCO.  These images and the 
hundreds of others taken by LASCO since it was launched on SOHO 
are giving us new views of CMEs and showing us the spectacular side of
the Sun!
====================================================================== 

Using LASCO and other instruments on SOHO we are learning more about how
CMEs are born.  LASCO shows us the very early stages in the development
of CMEs.

**CME birth image -- c1_arch2.gif**
=======================================================================
Caption:

Both these images were taken by the C1 LASCO telescope.  They show a 
CME (loop shape) as it pushes its way through the corona.  The image
on the left shows light emitted by the very hot gas in the corona and
the image on the right shows light that is scattered from electrons in
the corona.
========================================================================

We have also learned that a lot of CME accelerate as they move
away from the Sun.  They have a wide range of speeds but generally they
travel at about a million miles an hour.  

**Halo image -- halo2.gif**

========================================================================
Caption:

Watch out! CME on the way!  LASCO C3 catches a CME as it heads towards
the Earth.  Notice that it forms a ring around the Sun and that the 
white circle in the center marks the position and size of the Sun.
========================================================================

We can see more CMEs with LASCO than with earlier instruments because
LASCO is more sensitive.  We can watch CMEs as they move far into space
and because LASCO watches the Sun nearly all the time it gives us
warnings of when solar storms are going to hit the Earth.
Hopefully with the help of other instruments on SOHO we will be able to
predict when CMEs are likely to form and come towards Earth.  This
would be of great benefit to mankind since the charged particles in
CMEs can cause a lot of disruption to modern communications and power lines.