The star HD 140283 has been called the "Methuselah star" for its extreme age. At an estimated over 14 billion years old, it’s the oldest star we know, at least within our galaxy. A star that old is certainly interesting, particularly when it is so close to us it can be seen with binoculars, however, that appears to put it older than the universe. How that can be? A closer examination reveals the star is special, but not that special.
The standard estimate of the time since the Big Bang is 13.79 billion years. The figure is derived from the rate of expansion of the universe using Einstein's relativity but has been validated through a variety of methods. However, that number is now facing at least three distinct challenges. As evidence, proponents point to the existence of stars estimated to be either older than 13.8 billion years, or so close to that age that there shouldn’t have been time for them to form.
Not surprisingly HD 140283 gets prime billing (helped by its catchy nickname derived from a Biblical ancestor of Noah said to have lived to 969) due to a 2013 study using Hubble data that estimated it is 14.46 billion years old, plus or minus 800 million years. That would make it potentially older than the universe.
The biggest claim regarding HD 140283 is that it disproves the Big Bang. After all, if there is even one star 14.5 billion years old then the explosion that started the universe couldn’t have happened less than 14 billion years ago. The Big Bang is now so central to our cosmology that were it to be disproved it would create a scientific revolution the like of which we have not seen for a long time.
A smaller, but still dramatic, change would be required to adapt to the recent claim that the Big Bang happened, but almost twice as long ago as most estimates put it, at 26.7 billion years ago.
Neither of these views has much support among astrophysicists, but some do suspect we’ve got our estimates of the timing of the Big Bang more modestly wrong, and the universe is really around 15 billion years old. Although such an estimate would raise a few questions about why our estimates for the universe’s expansion rate are out, if proven, accompanying changes to our thinking would be evolutionary not revolutionary.
In that context, it’s worth asking: if the universe was 26 billion years old, wouldn’t we expect to find 20 billion-year-old stars? It’s true we’ve only really looked across a small portion of the galaxy, but if the universe is that old, Methuselah looks suspiciously young. Then take that question a step further and ask what we might expect to see if the universe had no beginning and has always been here. READ MORE...
