Happy Halloween, Everyone!

Wed. 11/6: We'll be closed tonight - we expect lots of clouds rolling in after sunset. We'll try again next week!

Astronomy Word of the Day

The Magellanic Clouds are two small, irregular dwarf galaxies outside of the Milky Way. These two galaxies are visible in the skies of the southern hemisphere, close to the South Celestial Pole, so they don't appear to set!

Image: https://aaa.org/.../01/southern-skies-the-magellanic-clouds/

If galaxies could talk, we’d want to ask for this galaxy’s skincare routine!

Meet I Zwicky 18, a galaxy lying 60 million light-years away in the constellation Ursa Major.

The bluish-white knots in the center are regions where stars are forming at a rapid rate. These large hubs of stellar creation and the lack of heavy elements in the surrounding gas caused astronomers to think that this dwarf irregular galaxy was very young, since it resembles galaxies in the early universe.

However, the Hubble Space Telescope revealed that I Zwicky 18 is more mature than it first appears. Hubble found faint, older stars within the galaxy, indicating that I Zwicky 18 has been forming stars for more than a billion years.

Credit: NASA, ESA, A. Aloisi (Space Telescope Science Institute and European Space Agency).

ALT TEXT: A bright white and blue oval-shaped area takes up most of the view and is largely centered. Cloud-like wisps of blue material surround the bright-white center, forming a fluffy wreath-like shape. The fluffy material begins as light blue near the center and gradually darkens moving outward. Stars, seen as many bright white and yellow small points of light, are densely grouped in the white and light blue region, forming two roughly circular clumps, one in the upper left and one in the lower right. The corners of the image are dark and mostly empty, with a few larger, fuzzy yellow points of light scattered infrequently throughout.

Wed. Nov. 1: Cloudy tonight. The observatory will be closed.

2024 February 4

The Cone Nebula from Hubble Image Credit: Hubble Legacy Archive, NASA, ESA - Processing & Licence: Judy Schmidt

Explanation: Stars are forming in the gigantic dust pillar called the Cone Nebula. Cones, pillars, and majestic flowing shapes abound in stellar nurseries where natal clouds of gas and dust are buffeted by energetic winds from newborn stars. The Cone Nebula, a well-known example, lies within the bright galactic star-forming region NGC 2264. The Cone was captured in unprecedented detail in this close-up composite of several observations from the Earth-orbiting Hubble Space Telescope. While the Cone Nebula, about 2,500 light-years away in Monoceros, is around 7 light-years long, the region pictured here surrounding the cone’s blunted head is a mere 2.5 light-years across. In our neck of the galaxy that distance is just over half way from our Sun to its nearest stellar neighbors in the Alpha Centauri star system. The massive star NGC 2264 IRS, seen by Hubble’s infrared camera in 1997, is the likely source of the wind sculpting the Cone Nebula and lies off the top of the image. The Cone Nebula’s reddish veil is produced by dust and glowing hydrogen gas.

∞ Source: apod.nasa.gov/apod/ap240204.html

Every February 2, we wonder if Punxsutawney Phil will see his shadow.

In Saturn’s case, astronomers know some of Saturn’s moons will cast shadows across the planet’s iconic rings every 15 years. This effect only occurs when the planet’s rings are perpendicular to the Sun. The next time this will happen is in May 2025.

Watch as four of Saturn’s moons orbit the planet, based on images taken by the Hubble Space Telescope over a 9.5-hour span in 1995. Enceladus is first and Mimas is close behind. Both of these moons cast small shadows on Saturn, but among the two, only Enceladus’ shadow cuts across the rings. Dione follows next and casts a long shadow across the planet’s rings. About 12 seconds in, the moon Tethys moves swiftly behind the planet toward the right.

Credit: NASA/ESA/STScI.

The Needle Galaxy, NGC 4565 // Michael Cole

We were extremely fortunate to have Jocelyn Bell Burnell as a virtual guest in a women in science class! She was a pleasure to listen to and continues to be an inspiration.

Navigating Deep Space by Starlight

On August 6, 1967, astrophysicist Jocelyn Bell Burnell noticed a blip in her radio telescope data. And then another. Eventually, Bell Burnell figured out that these blips, or pulses, were not from people or machines.

The blips were constant. There was something in space that was pulsing in a regular pattern, and Bell Burnell figured out that it was a pulsar: a rapidly spinning neutron star emitting beams of light. Neutron stars are superdense objects created when a massive star dies. Not only are they dense, but neutron stars can also spin really fast! Every star we observe spins, and due to a property called angular momentum, as a collapsing star gets smaller and denser, it spins faster. It’s like how ice skaters spin faster as they bring their arms closer to their bodies and make the space that they take up smaller.

The pulses of light coming from these whirling stars are like the beacons spinning at the tops of lighthouses that help sailors safely approach the shore. As the pulsar spins, beams of radio waves (and other types of light) are swept out into the universe with each turn. The light appears and disappears from our view each time the star rotates.

After decades of studying pulsars, astronomers wondered—could they serve as cosmic beacons to help future space explorers navigate the universe? To see if it could work, scientists needed to do some testing!

First, it was important to gather more data. NASA’s NICER, or Neutron star Interior Composition Explorer, is a telescope that was installed aboard the International Space Station in 2017. Its goal is to find out things about neutron stars like their sizes and densities, using an array of 56 special X-ray concentrators and sensitive detectors to capture and measure pulsars’ light.

But how can we use these X-ray pulses as navigational tools? Enter SEXTANT, or Station Explorer for X-ray Timing and Navigation Technology. If NICER was your phone, SEXTANT would be like an app on it.  

During the first few years of NICER’s observations, SEXTANT created an on-board navigation system using NICER’s pulsar data. It worked by measuring the consistent timing between each pulsar’s pulses to map a set of cosmic beacons.

When calculating position or location, extremely accurate timekeeping is essential. We usually rely on atomic clocks, which use the predictable fluctuations of atoms to tick away the seconds. These atomic clocks can be located on the ground or in space, like the ones on GPS satellites. However, our GPS system only works on or close to Earth, and onboard atomic clocks can be expensive and heavy. Using pulsar observations instead could give us free and reliable “clocks” for navigation. During its experiment, SEXTANT was able to successfully determine the space station’s orbital position!

We can calculate distances using the time taken for a signal to travel between two objects to determine a spacecraft’s approximate location relative to those objects. However, we would need to observe more pulsars to pinpoint a more exact location of a spacecraft. As SEXTANT gathered signals from multiple pulsars, it could more accurately derive its position in space.

So, imagine you are an astronaut on a lengthy journey to the outer solar system. You could use the technology developed by SEXTANT to help plot your course. Since pulsars are reliable and consistent in their spins, you wouldn’t need Wi-Fi or cell service to figure out where you were in relation to your destination. The pulsar-based navigation data could even help you figure out your ETA!

None of these missions or experiments would be possible without Jocelyn Bell Burnell’s keen eye for an odd spot in her radio data decades ago, which set the stage for the idea to use spinning neutron stars as a celestial GPS. Her contribution to the field of astrophysics laid the groundwork for research benefitting the people of the future, who yearn to sail amongst the stars.  

Keep up with the latest NICER news by following NASA Universe on X and Facebook and check out the mission’s website. For more on space navigation, follow @NASASCaN on X or visit NASA’s Space Communications and Navigation website.  

Make sure to follow us on Tumblr for your regular dose of space!

Our supply of eclipse glasses is running very low.

I see an angry fox about to breathe fire.

Hind's Variable Nebula, NGC 1555 // Rocco Sung