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The two spiral arms winding towards the bright centre might deceive you into thinking you are looking at a galaxy a bit like our Milky Way. But the object starring in this image is of a different nature: PK 329-02.2 is a ‘planetary nebula’ within our home galaxy. https://lnkd.in/ehBKkbqy View in LinkedIn

MORE EVIDENCE. “Additional evidence for dark matter comes from the stability of disk galaxies. Self-gravitating disks form bars (‘bar instability’) unless they have large velocity dispersion. Embedding disks in a massive, extended, roughly spherical halo is a solution to this problem.” https://lnkd.in/e6ifiQMn View in LinkedIn

KEY EVIDENCE. “Some of the most straightforward and long standing evidence for DM comes from the rotation curves of spiral galaxies. In a spiral galaxy stars and gas clouds move in circular orbits due to gravity, and their speeds can be measured using the Doppler shift of the Hydrogen 21cm line.” (DM = dark matter). https://lnkd.in/e6ifiQMn View in LinkedIn

OVERVIEW. “In this section we’ll look at the observational evidence for cold, non-baryonic dark matter, starting with galaxies, before moving out in scale to galaxy clusters, the cosmic microwave background anisotropies and large scale structure.” https://lnkd.in/e6ifiQMn View in LinkedIn

STAGE 5. TODAY. The age of the Universe, t0, (i.e. how long after the Big Bang ‘today’ is) is calculated for a ΛCDM universe https://lnkd.in/e6ifiQMn View in LinkedIn

STAGE 4. STRUCTURE FORMATION. “Structures start forming at ∼ 0.1 Gyr, and then Λ, or dark energy, comes to dominate the Universe, causing its expansion to accelerate, at t ∼ 10 Gyr.” https://lnkd.in/e6ifiQMn View in LinkedIn

YORKSHIRE PUDDING. “When wheat flour began to come into common use for making cakes and puddings, cooks in northern England (Yorkshire) devised a means of making use of the fat that dropped into the dripping pan to cook a batter pudding while the meat roasted. In 1737, a recipe for "a dripping pudding" was published.” https://lnkd.in/ejcUhJym. View in LinkedIn

OFF THE RADAR. “While philosophers and religious scholars have explored awe for centuries, it was largely ignored by psychologists until the early 2000s.” https://lnkd.in/eTQYza-q View in LinkedIn

STAGE 3. RECOMBINATION AND DECOUPLING. “0.3Myr). Structures start forming at ∼ 0.1 Gyr, and then Λ, or dark energy, comes to dominate the Universe, causing its expansion to accelerate, at t ∼ 10 Gyr.” https://lnkd.in/e6ifiQMn View in LinkedIn

STAGE 2. RADIATION-MATTER EQUALITY. “The matter dominated era starts at t ∼ 0.05 Myr, with the formation of atoms and the ‘release’ of the CMB occurring shortly after (t ∼ 0.3Myr).” (CMB = cosmic microwave background). https://lnkd.in/e6ifiQMn View in LinkedIn