Astronomy

To keep long-term moon residents safe from harmful radiation, lunar bases will need to be built several metres under the surface or inside caves or lava tubes

To keep long-term moon residents safe from harmful radiation, lunar bases will need to be built several metres under the surface or inside caves or lava tubes

Combining two neural networks has helped researchers predict potentially disastrous collapses in complex systems, such as financial crashes or power blackouts

Combining two neural networks has helped researchers predict potentially disastrous collapses in complex systems, such as financial crashes or power blackouts

New James Webb Space Telescope observations of LHS 1140b hint at a temperate water world with a nitrogen-rich atmosphere.

The post A Closer Look at a Potential "Eyeball Planet" appeared first on Sky & Telescope.

The Olympics are a sustainability nightmare, and Paris, despite its efforts, is no exception

NASA's Artemis 2, a round-the-moon mission with astronauts, is scheduled for a 2025 liftoff. But as backup astronaut Andre Douglas notes, safety will come before schedules on the pioneering effort.

An orange layer on the tips of Komodo dragons’ teeth may give the enamel extra strength for ripping apart their prey

An orange layer on the tips of Komodo dragons’ teeth may give the enamel extra strength for ripping apart their prey

An athletic trainer explains why bodies need time to acclimatize to extreme heat and what risks to watch out for to avoid heat illness in student athletes

The VIPER lunar rover promised a revolution in our understanding of the moon’s precious deposits of ice. Then NASA cancelled the mission

After helping millions of people plan their trips around the world, Tripadvisor is ready to do the same for those looking to travel beyond Earth. "Destination Space" is focused on space tourism.

Advanced meditation is changing how we think about consciousness. Hear neuroscience researcher Matthew Sacchet explain his journey to studying what happens to the brain during a deeper engagement with meditation.

Launched less than two months ago, ESA’s EarthCARE satellite has already returned images from two of its four instruments. Now, it has also delivered the first images from its multispectral imager, showcasing various types of clouds and cloud temperatures worldwide. This instrument is set to add valuable context to the data from EarthCARE’s other instruments.

Researchers are calling for greater protection for basking sharks after a camera on a tagged shark recorded a collision for the first time

Researchers are calling for greater protection for basking sharks after a camera on a tagged shark recorded a collision for the first time

In an effort to understand ancient Neanderthal food preparation techniques, researchers butchered five wild birds using flint stone tools and roasted them

In an effort to understand ancient Neanderthal food preparation techniques, researchers butchered five wild birds using flint stone tools and roasted them

Think about background radiation and most people immediately think of the cosmic background radiation and stories of pigeon excrement during its discovery. That’s for another day though. Turns out that the universe has several background radiations, such as infrared and even gravitational wave backgrounds. NASA’s New Horizons is far enough out of the Solar System now that it’s in the perfect place to measure the cosmic optical background (COB). Most of this light comes from the stars in galaxies, but astronomers have always wondered if there are other sources of light filling our night sky. New Horizons has an answer. No!

Ok lets talk pigeon excrement.  Back in 1965 two telecommunication engineers were exploring signal interference at the Bell Laboratory. Penzias and Wilson detected a faint ‘hum’ in all directions and initially put it down to pigeon excrement as they nested in the horn of the radio receiver. Instead, what they had discovered was the cosmic background radiation, the faint glow that permeates the entire universe and is the thermal radiation left over from the Big Bang. Studying it allows us to understand more about the Universe when it was 380,000 years old. 

The full-sky image of the temperature fluctuations (shown as color differences) in the cosmic microwave background, made from nine years of WMAP observations. These are the seeds of galaxies, from a time when the universe was under 400,000 years old. Credit: NASA/WMAP

In the late 80’s a different type of background radiation was detected; the infrared background radiation. It consists of the diffuse infrared glow that fills the universe coming from numerous sources throughout the history of the universe. It is mostly from thermal emissions from dust grains heated by stellar radiation. In addition to this is the gravity wave background although this has yet to be detected. 

Another hotly debated background is the cosmic optical background (COB), a diffuse light which originates from stars and galaxies and spans the whole of the visible spectrum. There has been gathering momentum in its study however with observations from Hubble Space Telescope and the Spitzer Infrared Telescope. The studies however revealed that a large contribution to a general background optical glow come from faint unresolved galaxies. The study of the COB allows us to explore the total energy output of the universe, about galaxy and star formation across the history of the cosmos. 

The detection of the COB is a challenging one however with Earth based instruments or even those in Earth orbit plagued by interference. The zodiacal light for example is the result of sunlight scattered by interplanetary dust, it is dominant in the inner solar system  and makes studies of the COB difficult. The New Horizon probe is ideally positioned out beyond the orbit of Pluto over 8 billion kilometres away from interference. On board New Horizons is the LORRI (Long Range Reconnaissance Imager) camera which was identified as an ideal platform to begin a search. 

The New Horizons instrument payload that is currently doing planetary science, heliospheric measurements, and astrophysical observations. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Using images from the LORRI camera, a team of astronomers led by Marc Postman from the Space Telescope Science Institute attempted to measure the COB over the range 0.4 to 0.9 micrometers. The images were from high galactic latitudes to ensure no diffuse light from the Milky Way or scattered light from bright stars. Isolating the COB contribution to the total sky brightness levels required digitally subtracting the scattered light from bright stars and galaxies and from faint stars within the field that were fainter than that detectable by LORRI. Interestingly, the results showed that, based on the estimated galaxy counts in the sampled regions the COB is the result of light from all the galaxies within our observable region of the universe.

Source : New Synoptic Observations of the Cosmic Optical Background with New Horizons

The post New Horizons Measures the Background Light of the Universe appeared first on Universe Today.