Welcome to Learn the Sky, your online resource for learning about the constellations and how to find
them. If you're new to this channel be sure to click the subscribe button and hit the bell for
notifications about new videos. Learn the Sky is also on Patreon, so if you'd like to support this
channel the link is listed below, and finally if you would like to study the sky in greater detail
and need a guide visit learnthesky.com to learn more about our online classes we offer. Welcome, my
name is Janine and in this video we will learn about the astronomical phenomenon known as a
zodiacal light, which is also sometimes called false dawn. This event is caused by sunlight scattering
from cosmic dust in the plane of our Earth's orbit. The best time to see zodiacal light is at sunset
towards the west since the sun sets in the west, but it can also be seen at sunrise right before
the Sun rises in the east, and it also depends on the time in which you go out to observe. In the
higher latitudes it's easier to see the zodiacal light in the early spring and late fall, but if you
happen to live in the tropical latitudes you can see this phenomenon all year round. Zodiacal
light often has a conical shape to it, and it forms when sunlight is reflected off the dust in
the plane of our solar system. The zodiacal light aligns with the ecliptic ,the path of the moon and
the Sun. So here you can see two planets right within the zodiacal light. That's Venus, and we
have Mars right here. Zodiacal light looks different than the Milky Way galaxy because the light is
more diffuse and uniform. The Milky Way over here in comparison has patches of concentrated light as
well as darker areas. The absence of light in these dark areas are due to gas being absorbed by clouds
within the galaxy, but here you can see the light is just more uniform. So that's the difference between
Zodical and light that comes from the Milky Way galaxy. The best time to observe
the zodiacal light is when the Moon is absent, so this would be in the new moon phase or even during
the third quarter phase since the moon doesn't rise until very late in the evening. Remember
it is best to see the zodiacal light at sunset or sunrise. The zodiacal light aligns with the
ecliptic, which is the path of the Moon and Sun. Here is highlighted in yellow. So the brightness
of the zodiacal light decreases with distance from the Sun. So that's why it's best to see
this phenomenon during the equinoxes. To see the zodiacal light a very dark sky is needed. The glow
of the light is so faint that any type of natural or artificial light pollution renders it invisible.
To see the zodiac light avoid any type of light pollution, both artificial and natural. Natural
light pollution of course would be the moon where we have artificial light pollution which would be
city lights. As the human population continues to grow so does light pollution. The International
dark-sky places program promotes preservation and protection of night skies across the globe, which
include communities, parks, and reserve. Check out the International Dark-Sky Association to
discover more about certified dark sky parks. So what causes this phenomenon? In short cosmic dust .
Cosmic dust consists of tiny microscopic particles that are floating in the space between planets in
the solar system. Collectively this dust makes up what we call the Interplanetary Dust Cloud,
or a zodiacal cloud. It pervades the space in between everything in the solar system that sits
in the ecliptic plane. These dust grains called Interplanetary Dust Particles or IDPs are very
tiny, but collectively they create a cone of light seen off the horizon which is called the zodiacal
light. IDPs are thought to come from asteroid collisions, comet collisions within the inner
solar system, or even from dust from comets and other types of collisions that might happen in
the solar system. Over 85% of this dust is really attributed to fragments that are located within
the inner solar system, or sometimes we call these Jupiter family comets that are pretty dormant and
lasts less than 20 years. So some of these dust particles aren't really actively outgassing but
might do so in the future. Remember that seeing the zodiacal light depends upon your location on the
earth and the time of year. In the mid-latitudes you look towards the west during the spring
equinox at twilight. During the autumn equinox look towards the eastern sky before dawn. Remember that
zodiacal light can also be called false dawn when it is seen before sunrise. If you happen to live
in a tropical region it is possible to see the zodiacal night throughout the year. When I lived
in Hawaii I saw this phenomenon at other times besides the equinoxes. It was definitely visible
when I observed from Mauna Kea, which are looking at here, and I also saw it whenever I
was sailing on the ocean at nighttime. The key was being away from light pollution. So let's
review everything we learned about zodiacal light so far. It is this diffuse column of light that
comes off the horizon, and it comes from sunlight reflecting off ddust in the plane of the solar
system. It depends upon where your location is on the planet. On the mid-latitudes you can see it
during the spring and autumn equinoxes, but if you're in the tropics you can see it all year
round. The key to seeing this is avoiding natural and artificial light pollution such as the moon
or city lights, and often you can see planets right within this cone of light that comes right off the
horizon. I love this picture because it shows you the difference between what the Milky Way would
look like, and then what the zodiacal light would look like as well. So I wish you luck being able to
see this amazing astronomical phenomenon. It's one of those favorite things of mine that when I see
it I just have to tell others that are around me like 'look look, you can see the zodiacal light' it's
really really beautiful. So thanks for watching. Good luck trying to find this and keep looking up!